To understand the chemical basis of inheritance, we must understand the molecular structure of DNA. This is an example of the application of which concept to the study of biology?
A) evolution
B) emergent properties
C) reductionism
D) the cell theory
E) feedback regulation

c

Once labor begins in childbirth, contractions increase in intensity and frequency until delivery. The increasing labor contractions of childbirth are an example of which type of regulation?
A) a bioinformatic system
B) positive feedback
C) negative feedback
D) feedback inhibition
E) enzymatic catalysis

B

When the body's blood glucose level rises, the pancreas secretes insulin and, as a result, the blood glucose level declines. When the blood glucose level is low, the pancreas secretes glucagon and, as a result, the blood glucose level rises. Such regulation of the blood glucose level is the result of
A) catalytic feedback
B) positive feedback
C) negative feedback
D) bioinformatic regulation
E) protein-protein interactions

C

Which branch of biology is concerned with the naming and classifying of organisms?
A) informatics
B) schematic biology
C) taxonomy
D) genomics
E) evolution

C

Prokaryotic and eukaryotic cells generally have which of the following features in common?
A) a membrane-bounded nucleus
B) a cell wall made of cellulose
C) ribosomes
D) flagella or cilia that contain microtubules
E) linear chromosomes made of DNA and protein

c

Prokaryotes are classified as belonging to two different domains. What are the domains?
A) Bacteria and Eukarya
B) Archaea and Monera
C) Eukarya and Monera
D) Bacteria and Protista
E) Bacteria and Archaea

E

Global warming, as demonstrated by observations such as melting of glaciers, increasing CO2 levels, and increasing average ambient temperatures, has already had many effects on living organisms. Which of the following might best offer a solution to this problem?
A) Continue to measure these and other parameters of the problem.
B) Increase the abilities of animals to migrate to more suitable habitats.
C) Do nothing; nature will attain its own balance.
D) Limit the burning of fossil fuels and regulate our loss of forested areas.
E) Recycle as much as possible.

D

A water sample from a hot thermal vent contained a single-celled organism that had a cell wall but lacked a nucleus. What is its most likely classification?
A) Eukarya
B) Archaea
C) Animalia
D) Protista
E) Fungi

B

A filamentous organism has been isolated from decomposing organic matter. This organism has a cell wall but no chloroplasts. How would you classify this organism?
A) domain Bacteria, kingdom Prokaryota
B) domain Archaea, kingdom Bacteria
C) domain Eukarya, kingdom Plantae
D) domain Eukarya, kingdom Protista
E) domain Eukarya, kingdom Fungi

E

Which of these provides evidence of the common ancestry of all life?
A) ubiquitous use of catalysts by living systems
B) near universality of the genetic code
C) structure of the nucleus
D) structure of cilia
E) structure of chloroplasts

B

Which of the following is (are) true of natural selection?
A) It requires genetic variation.
B) It results in descent with modification.
C) It involves differential reproductive success.
D) It results in descent with modification and involves differential reproductive success.
E) It requires genetic variation, results in descent with modification, and involves differential reproductive success.

E

Charles Darwin proposed a mechanism for descent with modification that stated that organisms of a particular species are adapted to their environment when they possess
A) non-inheritable traits that enhance their survival in the local environment.
B) non-inheritable traits that enhance their reproductive success in the local environment.
C) non-inheritable traits that enhance their survival and reproductive success in the local environment.
D) inheritable traits that enhance their survival and reproductive success in the local environment.
E) inheritable traits that decrease their survival and reproductive success in the local environment.

D

Which of these individuals is likely to be most successful in an evolutionary sense?
A) a reproductively sterile individual who never falls ill
B) an organism that dies after five days of life but leaves 10 offspring, all of whom survive to reproduce
C) a male who mates with 20 females and fathers one offspring
D) an organism that lives 100 years and leaves two offspring, both of whom survive to reproduce
E) a female who mates with 20 males and produces one offspring that lives to reproduce

B

In a hypothetical world, every 50 years people over 6 feet tall are eliminated from the population before they reproduce. Based on your knowledge of natural selection, you would predict that the average height of the human population will
A) remain unchanged.
B) gradually decline.
C) rapidly decline.
D) gradually increase.
E) rapidly increase.

B

Through time, the lineage that led to modern whales shows a change from four-limbed land animals to aquatic animals with two limbs that function as flippers. This change is best explained by
A) natural philosophy.
B) creationism.
C) the hierarchy of the biological organization of life.
D) natural selection.
E) feedback inhibition.

D

What is the major difference between a kingdom and a domain?
A) A kingdom can include several subgroups known as domains.
B) All eukarya belong to one domain.
C) All prokaryotes belong to one domain.
D) The importance of fungi has led scientists to make them the whole of one domain.
E) Only organisms that produce their own food belong to one of the domains.

B

Which of the following best describes what occurred after the publication of Charles Darwin's On the Origin of Species?
A) The book received little attention except from a small scientific community.
B) The book was banned from schools.
C) The book was widely discussed and disseminated.
D) The book's authorship was disputed.
E) The book was discredited by most scientists.

C

Why is Darwin considered original in his thinking?
A) He provided examples of organisms that had evolved over time.
B) He demonstrated that evolution is continuing to occur now.
C) He described the relationship between genes and evolution.
D) He proposed the mechanism that explained how evolution takes place.
E) He observed that organisms produce large numbers of offspring.

D

Darwin's finches, collected from the Galápagos Islands, illustrate which of the following?
A) mutation frequency
B) ancestors from different regions
C) adaptive radiation
D) vestigial anatomic structures
E) the accuracy of the fossil record

C

Which of the following categories of organisms is least likely to be revised?
A) kingdom
B) class
C) order
D) phylum
E) species

E

What is the major distinguishing characteristic of fungi?
A) gaining nutrition through ingestion
B) being sedentary
C) being prokaryotic
D) absorbing dissolved nutrients
E) being decomposers of dead organisms

D

What are archaea?
A) Prokaryotes characterized as extremophiles that share some bacterial and some eukaryotic traits.
B) Organisms that are adapted to high temperature environments, such as in volcanic springs.
C) Single-celled organisms that are killed by the application of antibiotics at certain concentrations.
D) Bacteria-like organisms that can live only in extreme salt environments.
E) Primitive protist-like creatures possessing fewer than two chromosomes per cell.

A

According to Darwinian theory, which of the following exhibits the greatest fitness for evolutionary success?
A) the species with the longest life
B) the individuals within a population that have the greatest reproductive success
C) the phylum with members that occupy the greatest number of habitats
D) the community of organisms that is capable of living in the most nutrient-poor biome
E) the organism that produces its own nutrients most efficiently

B

Similarities and differences among/between life-forms over time are most efficiently recorded by scientists in which field(s) of study?
A) paleontology
B) paleontology and anatomy
C) paleontology, anatomy, and taxonomy
D) paleontology, anatomy, taxonomy, and genetics
E) paleontology, anatomy, taxonomy, genetics, and ecology

E

Why is the theme of evolution considered to be the core theme of biology by biologists?
A) It provides a framework within which all biological investigation makes sense.
B) It is recognized as the core theme of biology by organizations such as the National Science Foundation.
C) Controversy about this theory provides a basis for a great deal of experimental research.
D) Since it cannot be proven, biologists will be able to study evolutionary possibilities for many years.
E) Biologists do not subscribe to alternative models.

A

The method of scientific inquiry that describes natural structures and processes as accurately as possible through careful observation and the analysis of data is known as
A) hypothesis-based science.
B) discovery science.
C) experimental science.
D) quantitative science.
E) qualitative science.

B

Collecting data based on observation is an example of ________; analyzing this data to reach a conclusion is an example of ________ reasoning.
A) hypothesis-based science; inductive
B) the process of science; deductive
C) discovery science; inductive
D) descriptive science; deductive
E) hypothesis-based science; deductive

C

When applying the process of science, which of these is tested?
A) a question
B) a result
C) an observation
D) a prediction
E) a hypothesis

D

A controlled experiment is one in which
A) the experiment is repeated many times to ensure that the results are accurate.
B) the experiment proceeds at a slow pace to guarantee that the scientist can carefully observe all reactions and process all experimental data.
C) there are at least two groups, one of which does not receive the experimental treatment.
D) there are at least two groups, one differing from the other by two or more variables.
E) there is one group for which the scientist controls all variables.

C

Why is it important that an experiment include a control group?
A) The control group is the group that the researcher is in control of, the group in which the researcher predetermines the results.
B) The control group provides a reserve of experimental subjects.
C) A control group is required for the development of an "If…then" statement.
D) A control group assures that an experiment will be repeatable.
E) Without a control group, there is no basis for knowing if a particular result is due to the variable being tested.

E

The application of scientific knowledge for some specific purpose is known as
A) technology.
B) deductive science.
C) inductive science.
D) anthropologic science.
E) pure science.

A

Which of the following are qualities of any good scientific hypothesis?
I. It is testable.
II. It is falsifiable.
III. It produces quantitative data.
IV. It produces results that can be replicated.
A) I only
B) II only
C) III only
D) I and II
E) III and IV

D

When a hypothesis cannot be written in an "If…then" format, what does this mean?
A) It does not represent deductive reasoning.
B) It cannot be a scientific hypothesis.
C) The subject cannot be explored scientifically.
D) The hypothesizer does not have sufficient information.
E) It cannot be testable.

A

In presenting data that result from an experiment, a group of students show that most of their measurements fall on a straight diagonal line on their graph. However, two of their data points are "outliers" and fall far to one side of the expected relationship. What should they do?
A) Do not show these points but write a footnote that the graph represents the correct data.
B) Average several trials and therefore rule out the improbable results.
C) Show all results obtained and then try to explore the reason(s) for these outliers.
D) Throw out this set of data and try again.
E) Change the details of the experiment until they can obtain the expected results.

C

Which of the following is the best description of a control for an experiment?
A) The control group is kept in an unchanging environment.
B) The control is left alone by the experimenters.
C) The control group is matched with the experimental group except for the one experimental variable.
D) The control group is exposed to only one variable rather than several.
E) Only the experimental group is tested or measured.

C

Given the cooperativity of science, which of the following is most likely to result in an investigator being intellectually looked down upon by other scientists?
A) Making money as the result of studies in which a new medication is discovered.
B) Doing meticulous experiments that show data that contradict what has been previously reported by the scientific community.
C) Spending most of a lifetime investigating a small and seemingly unimportant organism.
D) Getting negative results from the same set of experiments.
E) Being found to have falsified or created data to better fit a hypothesis.

E

Which of these is an example of inductive reasoning?
A) Hundreds of individuals of a species have been observed and all are photosynthetic; therefore, the species is photosynthetic.
B) These organisms live in sunny parts of this area so they are able to photosynthesize.
C) If horses are always found grazing on grass, they can be only herbivores and not omnivores.
D) If protists are all single-celled, then they are incapable of aggregating.
E) If two species are members of the same genus, they are more alike than each of them could be to a different genus.

A

In a high school laboratory, which of the following constitutes an experiment?
I. learning to use a microscope by examining fixed specimens on slides
II. being able to examine swimming protists under a microscope
III. extracting pigments from plant leaves and separating the types of pigments for identification
IV. preparing root tips for examination by staining them
A) I only
B) II only
C) III only
D) II and III only
E) II, III, and IV

C

Which of the following best describes a model organism?
A) It is often pictured in textbooks and easy for students to imagine.
B) It lends itself to many studies that are useful to beginning students.
C) It is well studied, easy to grow, and results are widely applicable.
D) It is small, inexpensive to raise, and lives a long time.
E) It has been chosen for study by the earliest biologists.

C

Why is a scientific topic best discussed by people of varying points of view, a variety of subdisciplines, and diverse cultures?
A) They can rectify each other's approach to make it truly scientific.
B) Robust and critical discussion between diverse groups improves scientific thinking.
C) Scientists can explain to others that they need to work in isolation to utilize the scientific method more productively.
D) This is another way of making science more reproducible.
E) Scientists need to exchange their ideas with other disciplines and cultures so that all groups are in consensus with the course of future research.

B

The illustration above most probably represents
A) a computer simulation of the structure of a eukaryotic cell.
B) a map of a network of protein interactions within a eukaryotic cell.
C) an inventory of all the genes in a fruit fly.
D) an X-ray diffraction image of the nucleus and cytoplasm of a eukaryotic cell.
E) a computer-generated map of the interaction of genes and cytoplasm in a prokaryotic cell.

B

What do these two plants have in common?
A) adaptations to extreme heat
B) adaptations to conserve water
C) identical stem structures
D) identical flower structures
E) lack of photosynthesis

B

Use the following information to answer questions 47 - 50.

Golden algae are a group of protists whose color is due to carotenoid pigments: yellow and brown. Most have two flagella and all are photosynthetic. A group of students was given a significant sample of one of these (Dinobryon) that is colonial. Their instructions for the project were to design two or more experiments that could be done with these organisms.

Since these organisms are protists, which of these characteristics could the students assume to be true?
A) The organisms are photosynthetic.
B) All of them are marine.
C) They are single-celled.
D) They lack membrane-bound organelles.
E) Each has a single circular molecule of DNA.

A

The students decide that for one of their experiments, they want to see whether the organisms can photosynthesize. Which of the following is the best hypothesis?
A) If the Dinobryon can live > 5 days without added food, they must be able to photosynthesize.
B) If the Dinobryon can live without exposure to light for > 5 days, they must be able to photosynthesize.
C) If the Dinobryon photosynthesize, they must need no other minerals or nutrients and will be able to live in distilled water and light alone.
D) If the Dinobryon are kept in the dark, one-half will be expected to die in 5 days.
E) If the Dinobryon are able to photosynthesize, the students should be able to extract photosynthetic pigments.

E

For their second experiment, the students want to know whether the Dinobryon have to live in colonies or can be free living. How might they proceed?
A) Observe each day to see whether new organisms are ever reproduced as single cells.
B) Observe whether only specialized cells are able to divide to produce new colonies.
C) Divide a sample into single cells and measure the length of time they remain this way.
D) Divide a sample into single cells and observe them.
E) Divide a sample into single cells and see whether they come back together.

C

The students plan to gather data from the project. Which of the following would be the best way to present what they gather from experimental groups as opposed to controls?
A) qualitatively, noting color, size, and so on
B) measuring the number of new colonies formed during every 12-hour period
C) counting the number of new colonies after a week
D) measuring the size of each new colony in millimeters (mm) of length
E) measuring the dry weight of all new colonies in grams

B

The following is a list of biology themes discussed in Chapter 1. Use them to answer questions 51 - 54.

I. New properties emerge at each level in the biological hierarchy.
II. Organisms interact with other organisms and the physical environment.
III. Life requires energy transfer and transformation.
IV. Structure and function are correlated at all levels of biological organization.
V. Cells are an organism's basic units of structure and function.
VI. The continuity of life is based on heritable information in the form of DNA.
VII. Feedback mechanisms regulate biological systems.
VIII. Evolution accounts for the unity and diversity of life.

Which theme(s) is/are best illustrated by an experiment in which a biologist seeks a medication that will inhibit pain responses in a cancer patient?
A) II
B) VII
C) III and V
D) V and VIII
E) VI and VII

B

Which theme(s) is/are best illustrated by a group of investigators who are trying to classify and explain the ecology of an area known as the Big Thicket?
A) I only
B) II only
C) VIII only
D) IV and VI
E) I and II

E

Which theme(s) is/are illustrated when a group of students is trying to establish which phase of cell division in root tips happens most quickly?
A) IV only
B) V only
C) VII only
D) IV, V, and VI
E) V, VI, and VII

D

Which theme(s) is/are illustrated when a biology class is comparing the rates of photosynthesis between leaves of a flowering plant species (Gerbera jamesonii) and a species of fern (Polypodium polypodioides)?
A) I only
B) II only
C) I and III
D) I and VII
E) I, III, and V

E

Questions 55 - 64 are from the end-of-chapter "Test Your Understanding" section in Chapter 1 of the textbook.

All the organisms on your campus make up
A) an ecosystem.
B) a community.
C) a population.
D) an experimental group.
E) a taxonomic domain.

B

Which of the following is a correct sequence of levels in life's hierarchy, proceeding downward from an individual animal?
A) brain, organ system, nerve cell, nervous tissue
B) organ system, nervous tissue, brain
C) organism, organ system, tissue, cell, organ
D) nervous system, brain, nervous tissue, nerve cell
E) organ system, tissue, molecule, cell

D

Which of the following is not an observation or inference on which Darwin's theory of natural selection is based?
A) Poorly adapted individuals never produce offspring.
B) There is heritable variation among individuals.
C) Because of overproduction of offspring, there is competition for limited resources.
D) Individuals whose inherited characteristics best fit them to the environment will generally produce more offspring.
E) A population can become adapted to its environment over time.

A

Systems biology is mainly an attempt to
A) analyze genomes from different species.
B) simplify complex problems by reducing the system into smaller, less complex units.
C) understand the behavior of entire biological systems.
D) build high-throughput machines for the rapid acquisition of biological data.
E) speed up the technological application of scientific knowledge.

C

Protists and bacteria are grouped into different domains because
A) protists eat bacteria.
B) bacteria are not made of cells.
C) protists have a membrane-bounded nucleus, which bacterial cells lack.
D) bacteria decompose protists.
E) protists are photosynthetic.

C

Which of the following best demonstrates the unity among all organisms?
A) matching DNA nucleotide sequences
B) descent with modification
C) the structure and function of DNA
D) natural selection
E) emergent properties

C

A controlled experiment is one that
A) proceeds slowly enough that a scientist can make careful records of the results.
B) tests experimental and control groups in parallel.
C) is repeated many times to make sure the results are accurate.
D) keeps all variables constant.
E) is supervised by an experienced scientist.

B

Which of the following statements best distinguishes hypotheses from theories in science?
A) Theories are hypotheses that have been proved.
B) Hypotheses are guesses; theories are correct answers.
C) Hypotheses usually are relatively narrow in scope; theories have broad explanatory power.
D) Hypotheses and theories are essentially the same thing.
E) Theories are proved true; hypotheses are often falsified.

C

Which of the following is an example of qualitative data?
A) The temperature decreased from 20°C to 15°C.
B) The plant's height is 25 centimeters (cm).
C) The fish swam in a zigzag motion.
D) The six pairs of robins hatched an average of three chicks.
E) The contents of the stomach are mixed every 20 seconds.

C

Which of the following best describes the logic of scientific inquiry?
A) If I generate a testable hypothesis, tests and observations will support it.
B) If my prediction is correct, it will lead to a testable hypothesis.
C) If my observations are accurate, they will support my hypothesis.
D) If my hypothesis is correct, I can expect certain test results.
E) If my experiments are set up right, they will lead to a testable hypothesis.

D

About 25 of the 92 natural elements are known to be essential to life. Which four of these 25 elements make up approximately 96% of living matter?
A) carbon, sodium, hydrogen, nitrogen
B) carbon, oxygen, phosphorus, hydrogen
C) oxygen, hydrogen, calcium, nitrogen
D) carbon, hydrogen, nitrogen, oxygen
E) carbon, oxygen, nitrogen, calcium

D

Trace elements are those required by an organism in only minute quantities. Which of the following is a trace element that is required by humans and other vertebrates, but not by other organisms such as bacteria or plants?
A) nitrogen
B) calcium
C) iodine
D) sodium
E) phosphorus

C

Which of the following statements is false?
A) Carbon, hydrogen, oxygen, and nitrogen are the most abundant elements of living matter.
B) Some trace elements are very abundant on Earth.
C) Virtually all organisms require the same elements in the same quantities.
D) Iron is an example of an element needed by all organisms.
E) Other than some trace elements, animals are mostly made up of the same elements as plants, in similar proportions.

C

What factors are most important in determining which elements are most common in living matter?
A) the relative abundances of the elements in Earth's crust and atmosphere
B) the emergent properties of the simple compounds made from these elements
C) the reactivity of the elements with water
D) the chemical stability of the elements
E) both the relative abundances of the elements and the emergent properties of the compounds made from these elements

E

Why is each element unique and different from other elements in chemical properties?
A) Each element has a unique atomic mass.
B) Each element has a unique atomic weight.
C) Each element has a unique number of protons in its nucleus.
D) Each element has a unique number of neutrons in its nucleus.
E) Each element has different radioactive properties.

C

Knowing just the atomic mass of an element allows inferences about which of the following?
A) the chemical properties of the element
B) the number of protons in the element
C) the number of neutrons in the element
D) the number of protons plus neutrons in the element
E) both the number of protons and the chemical properties of the element

D

In what way are elements in the same column of the periodic table the same?
A) They have the same number of protons.
B) They have the same number of neutrons.
C) They have the same number of electrons.
D) They have the same number of electrons in their valence shell.
E) They have the same number of electron shells.

D

Oxygen has an atomic number of 8 and a mass number of 16. Thus, what is the atomic mass of an oxygen atom?
A) exactly 8 grams
B) exactly 8 daltons
C) approximately 16 grams
D) approximately 16 daltons
E) 24 amu (atomic mass units)

D

The nucleus of a nitrogen atom contains 7 neutrons and 7 protons. Which of the following is a correct statement concerning nitrogen?
A) The nitrogen atom has a mass number of approximately 7 daltons and an atomic mass of 14.
B) The nitrogen atom has a mass number of approximately 14 daltons and an atomic mass of 7.
C) The nitrogen atom has a mass number of 14 and an atomic mass of 7 grams.
D) The nitrogen atom has a mass number of 7 and an atomic number of 14.
E) The nitrogen atom has a mass number of 14 and an atomic mass of approximately 14 daltons.

E

Molybdenum has an atomic number of 42. Several common isotopes exist, with mass numbers of 92, 94, 95, 96, 97, 98, and 100. Therefore, which of the following can be true?
A) Molybdenum atoms can have between 50 and 58 neutrons.
B) The isotopes of molybdenum have different electron configurations.
C) The isotopes of molybdenum can have between 50 and 58 protons.
D) The isotopes of molybdenum have between 50 and 58 neutrons and have different electron configurations.
E) The isotopes of molybdenum have between 50 and 58 protons and have different electron configurations.

A

Carbon-12 is the most common isotope of carbon, and has an atomic mass of 12 daltons. A mole of carbon in naturally occurring coal, however, weighs slightly more than 12 grams. Why?
A) The atomic mass does not include the mass of electrons.
B) Some carbon atoms in nature have an extra proton.
C) Some carbon atoms in nature have more neutrons.
D) Some carbon atoms in nature have a different valence electron distribution.
E) Some carbon atoms in nature have undergone radioactive decay.

C

Which of the following best describes the relationship between the atoms described below? [SEE IMAGE]
A) They are isomers.
B) They are polymers.
C) They are isotopes.
D) They contain 1 and 3 protons, respectively.
E) They each contain 1 neutron.

C

The precise weight of a mole of some pure elements like silicon (Si) can vary slightly from the standard atomic mass, or even from sample to sample. Why?
A) The element may undergo radioactive decay.
B) The element may react with itself and gain or lose subatomic particles.
C) The atoms of the element form chemical bonds with each other, and that changes the weight of the element.
D) The element may have multiple stable isotopes, and the isotopic composition may vary from sample to sample.
E) The amount of energy absorbed by the element affects the mass of its electrons, and thus the atomic mass can vary slightly.

D

One difference between carbon-12 (12/6 C) is that carbon-14 (14/6 C) has
A) two more protons than carbon-12.
B) two more electrons than carbon-12.
C) two more neutrons than carbon-12.
D) two more protons and two more neutrons than carbon-12.
E) two more electrons and two more neutrons than carbon-12.

C

An atom has 6 electrons in its outer shell. How many unpaired electrons does it have?
A) 0
B) 2
C) 4
D) 6
E) 2 or 4

B

The atomic number of nitrogen is 7. Nitrogen-15 is heavier than nitrogen-14 because the atomic nucleus of nitrogen-15 contains how many neutrons?
A) 6
B) 7
C) 8
D) 12
E) 14

C

Electrons exist only at fixed levels of potential energy. However, if an atom absorbs sufficient energy, a possible result is that
A) an electron may move to an electron shell farther away from the nucleus.
B) an electron may move to an electron shell closer to the nucleus.
C) the atom may become a radioactive isotope.
D) the atom would become a positively charged ion, or cation, and become a radioactive isotope.
E) the atom would become a negatively charged ion, or anion.

A

The atomic number of neon is 10. Therefore, which of the following is most correct about an atom of neon?
A) It has 8 electrons in its outer electron shell.
B) It is inert.
C) It has an atomic mass of 10 daltons.
D) It has 8 electrons in its outer electron shell and it is inert.
E) It has 8 electrons in its outer electron shell, it is inert, and it has an atomic mass of 10 daltons.

D

From its atomic number of 15, it is possible to predict that the phosphorus atom has
A) 15 neutrons.
B) 15 protons.
C) 15 electrons.
D) 8 electrons in its outermost electron shell.
E) 15 protons and 15 electrons.

E

Atoms whose outer electron shells contain 8 electrons tend to
A) form ions in aqueous solutions.
B) form hydrogen bonds in aqueous solutions.
C) be stable and chemically nonreactive, or inert.
D) be gaseous at room temperature.
E) be both chemically inert and gaseous at room temperature.

E

The atomic number of each atom is given to the left of each of the elements below. Which of the atoms has the same valence as carbon (12/6 C)?
A) ₇N nitrogen
B) ₉F flourine
C) ₁₀Ne neon
D) ₁₂Mg magnesium
E) ₁₄Si silicon

E

Two atoms appear to have the same mass number. These atoms
A) must have the same atomic number.
B) must have the same number of electrons.
C) must have the same chemical properties.
D) must have the same number of protons + neutrons.
E) must have the same atomic number, the same number of protons + neutrons, the same number of electrons, and the same chemical properties.

D

Fluorine has an atomic number of 9 and a mass number of 19. How many electrons are needed to complete the valence shell of a fluorine atom?
A) 1
B) 3
C) 0
D) 7
E) 9

A

What is the maximum number of electrons in a single 2 p orbital of an atom?
A) 1
B) 2
C) 3
D) 4
E) 5

B

The organic molecules in living organisms have a measurably lower ratio of carbon-13/carbon-12, two stable isotopes of carbon that comprise approximately 1.1% and 98.9% of atmospheric carbon, respectively. What is a reasonable explanation for this phenomenon?
A) Photosynthesis preferentially uses carbon dioxide molecules with carbon-12, and the lower carbon-13/carbon-12 ratio propagates through the food chain.
B) Carbon dioxide molecules with carbon-13 stay in the upper atmosphere and are less available to terrestrial plants and algae.
C) Carbon-13 has a different valence electron configuration and is therefore less chemically reactive than carbon-12.
D) Oxygen atoms preferentially react with carbon-13, thereby enriching the atmosphere with carbon dioxide molecules containing carbon-13 atoms.
E) Carbon dioxide molecules containing carbon-13 are heavier and sink into the ocean depths, making them less available to living organisms.

A

Phosphorus-32, a radioactive isotope of phosphorus-31 (atomic number 15), undergoes a form of radioactive decay whereby a neutron turns into a proton and emits radiation in the form of an electron. What is the product of such radioactive decay of phosphorus-32?
A) phosphorus-31
B) a positively charged phosphorus-31 ion
C) a negatively charged phosphorus-32 ion
D) sulfur-32 (atomic number 16)
E) the conversion of the phosphorus-32 atom into pure energy

D

An atom with atomic number 12 would have what type of chemical behavior in bonding with other elements?
A) It would form ions with a +1 charge.
B) It would form ions with a +2 charge.
C) It would form ions with a -1 charge.
D) It would form ions with a -2 charge.
E) It would form two covalent bonds with other atoms.

B

If a salamander relied on hydrogen bonds to cling to surfaces, what type of surface would cause the most problems for this animal?
A) a surface coated with a thin film of water
B) a surface made with carbon and hydrogen atoms covalently bonded together
C) a surface made with carbon, hydrogen, and oxygen atoms covalently bonded together
D) a surface made with carbon, hydrogen, nitrogen, and oxygen atoms covalently bonded together
E) a surface made with silicon and oxygen atoms covalently bonded together

B

A covalent chemical bond is one in which
A) electrons are removed from one atom and transferred to another atom so that the two atoms become oppositely charged.
B) protons and neutrons are shared by two atoms so as to satisfy the requirements of both atoms.
C) outer-shell electrons of two atoms are shared so as to satisfactorily fill the outer electron shells of both atoms.
D) outer-shell electrons of one atom are transferred to fill the inner electron shell of another atom.
E) an electron occupies a hybrid orbital located between the nuclei of two atoms.

C

If an atom of sulfur (atomic number 16) were allowed to react with atoms of hydrogen (atomic number 1), which of the molecules below would be formed?

[SEE IMAGE FOR CHOICES]

B

What is the maximum number of covalent bonds an element with atomic number 8 can make with hydrogen?
A) 1
B) 2
C) 3
D) 4
E) 6

B

Nitrogen (N) is much more electronegative than hydrogen (H). Which of the following statements is correct about the atoms in ammonia (NH₃)?
A) Each hydrogen atom has a partial positive charge; the nitrogen atom has a partial negative charge.
B) The nitrogen atom has a strong positive charge; each hydrogen atom has a strong positive charge.
C) Each hydrogen atom has a slight negative charge; the nitrogen atom has a strong positive charge.
D) The nitrogen atom has a slight positive charge; each hydrogen atom has a slight negative charge.
E) There are covalent bonds between the hydrogen atoms and polar bonds between each hydrogen atom and the nitrogen atom.

A

When two atoms are equally electronegative, they will interact to form
A) hydrogen bonds.
B) van der Waals interactions.
C) polar covalent bonds.
D) nonpolar covalent bonds.
E) ionic bonds.

D

What results from an unequal sharing of electrons between atoms?
A) a nonpolar covalent bond
B) a polar covalent bond
C) an ionic bond
D) a hydrogen bond
E) a hydrophobic interaction

B

A covalent bond is likely to be polar when
A) one of the atoms sharing electrons is much more electronegative than the other atom.
B) the two atoms sharing electrons are equally electronegative.
C) oxygen is one of the two atoms sharing electrons.
D) one of the atoms has absorbed more energy than the other atom.
E) the two atoms sharing electrons are different elements.

A

Which of the following molecules contains the most polar covalent bond?
A) H₂
B) O₂
C) CO₂
D) H₂O
E) CH₄

D

In comparing covalent bonds and ionic bonds, which of the following would you expect?
A) An atom can form covalent bonds with multiple partner atoms, but only a single ionic bond with a single partner atom.
B) Covalent bonds and ionic bonds occupy opposite ends of a continuous spectrum, from nearly equal to completely unequal sharing of electrons.
C) Both involve electrical attraction between the electrons of one atom and the nucleus of the other atom.
D) Ionic interactions remain when covalent bonds are broken in water. Ionic bonds are much stronger than covalent bonds.

B

What is the difference between covalent bonds and ionic bonds?
A) Covalent bonds are formed between atoms to form molecules; ionic bonds are formed between atoms to form compounds.
B) Covalent bonds involve the sharing of pairs of electrons between atoms; ionic bonds involve the sharing of single electrons between atoms.
C) Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between atoms.
D) Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the sharing of protons between atoms.
E) Covalent bonds involve the transfer of electrons between atoms; ionic bonds involve the sharing of electrons between atoms.

C

In ammonium chloride salt (NH₄Cl) the anion is a single chloride ion, Cl. What is the cation of NH₄Cl?
A) N, with a charge of +1
B) NH, with a charge of +1
C) H₃, with a charge of +1
D) NH₄, with a charge of +1
E) NH₄, with a charge of +4

D

The atomic number of chlorine is 17. The atomic number of magnesium is 12. What is the formula for magnesium chloride?
A) MgCl
B) MgCl₂
C) Mg₂Cl
D) Mg₂Cl₂
E) MgCl₃

B

How many electron pairs are shared between carbon atoms in a molecule that has the formula C₂H₄?
A) 0
B) 1
C) 2
D) 3
E) 4

C

Which bond or interaction would be difficult to disrupt when compounds are put into water?
A) covalent bond
B) hydrogen bond
C) van der Waals interaction
D) ionic bond
E) either covalent bonds or ionic bonds

A

Which of the following explains most specifically the attraction of water molecules to one another?
A) nonpolar covalent bond
B) polar covalent bond
C) ionic bond
D) hydrogen bond
E) hydrophobic interaction

D

Van der Waals interactions result when
A) hybrid orbitals overlap.
B) electrons are not symmetrically distributed in a molecule.
C) molecules held by ionic bonds react with water.
D) two polar covalent bonds react.
E) a hydrogen atom loses an electron.

B

What bonding or interaction is most likely to occur among a broad array of molecules of various types (polar, nonpolar, hydrophilic, hydrophobic)?
A) covalent bonding
B) polar covalent bonding
C) ionic bonding
D) hydrogen bonding
E) van der Waals interactions

E

Which of the following is not considered to be a weak molecular interaction?
A) a covalent bond
B) a van der Waals interaction
C) an ionic bond in the presence of water
D) a hydrogen bond
E) both a hydrogen bond and a covalent bond

A

Which of the following would be regarded as compounds?
A) H₂O, O₂, and CH₄
B) H₂O and O₂
C) O₂ and CH₄
D) CH₄ and O₂, but not H₂O
E) H₂O and CH₄, but not O₂

E

What is the maximum number of hydrogen atoms that can be covalently bonded in a molecule containing two carbon atoms?
A) 2
B) 3
C) 4
D) 6
E) 8

D

Which of the following is true for this reaction?
3 H₂ + N₂ ↔ 2 NH₃
A) The reaction is nonreversible.
B) Hydrogen and nitrogen are the reactants of the reverse reaction.
C) Hydrogen and nitrogen are the products of the forward reaction.
D) Ammonia is being formed and decomposed.
E) Hydrogen and nitrogen are being decomposed.

D

Which of the following correctly describes chemical equilibrium?
A) Forward and reverse reactions continue with no effect on the concentrations of the reactants and products.
B) Concentrations of products are higher than the concentrations of the reactants.
C) Forward and reverse reactions have stopped so that the concentration of the reactants equals the concentration of the products.
D) Reactions stop only when all reactants have been converted to products.
E) There are equal concentrations of reactants and products, and the reactions have stopped.

A

Which of the following correctly describes any reaction that has reached chemical equilibrium?
A) The concentration of the reactants equals the concentration of the products.
B) The rate of the forward reaction is equal to the rate of the reverse reaction.
C) All of the reactants have been converted to the products of the reaction.
D) All of the products have been converted to the reactants of the reaction.
E) Both the forward and the reverse reactions have stopped with no net effect on the concentration of the reactants and the products.

B

Which of these systems is least likely to be at chemical equilibrium?
A) a test tube of living cells
B) a test tube of organic molecules, kept in the freezer
C) a test tube of dry organic molecules, kept at room temperature
D) a test tube of organic molecules dissolved in water, kept at room temperature
E) a test tube of dead cells in water, kept at room temperature

A

Refer to the figure above (first three rows of the periodic table). If life arose on a planet where carbon is absent, which element might fill the role of carbon?
A) boron
B) silicon
C) nitrogen
D) aluminum
E) phosphorus

B

Which drawing in the figure above depicts the electron configuration of an element with chemical properties most similar to Helium (₂He)?
A) A
B) B
C) C
D) D
E) E

E

Which drawing in the figure above depicts the electron configuration of an atom that can form covalent bonds with two hydrogen atoms?
A) A
B) B
C) C
D) D
E) E

C

Which drawing in the figure above depicts the electron configuration of an atom capable of forming three covalent bonds with other atoms?
A) A
B) B
C) C
D) D
E) E

B

Which drawing in the figure above is of the electron configuration of a sodium ₁₁Na⁺ ion?
A) A
B) B
C) C
D) D
E) E

E

Which drawing in the figure above depicts the most electronegative atom?
A) A
B) B
C) C
D) D
E) E

D

Which drawing in the figure above depicts an atom with a valence of 3?

B

Which drawing in the figure above depicts an atom with a valence of 2?
A) A
B) B
C) C
D) D
E) E

C

In the figure above, how many electrons does nitrogen have in its valence shell?
A) 2
B) 5
C) 7
D) 8
E) 14

B

In the figure above, how many unpaired electrons does phosphorus have in its valence shell?
A) 15
B) 2
C) 3
D) 7
E) 5

C

How many neutrons are present in the nucleus of a phosphorus-32 (³²P) atom (see the figure above)?
A) 5
B) 15
C) 16
D) 17
E) 32

D

How many electrons does an atom of sulfur have in its valence shell (see the figure above)?
A) 4
B) 6
C) 8
D) 16
E) 32

B

Based on electron configuration, which of these elements in the figure above would exhibit a chemical behavior most like that of oxygen?
A) carbon
B) hydrogen
C) nitrogen
D) sulfur
E) phosphorus

D

The illustration above shows a representation of formic acid. A formic acid molecule
A) will form hydrogen bonds with water molecules.
B) has a tetrahedral configuration of hybrid electron orbitals for the carbon atom.
C) consists of largely nonpolar covalent bonds.
D) is held together by hydrogen bonds.
E) has a tetrahedral shape and will form hydrogen bonds with water molecules.

A

What results from the chemical reaction illustrated above?
A) a cation with a net charge of +1
B) a cation with a net charge of -1
C) an anion with a net charge of +1
D) an anion with a net charge of -1
E) a cation with a net charge of +1 and an anion with a net charge of -1

E

What is the atomic number of the cation formed in the reaction illustrated above?
A) 1
B) 8
C) 10
D) 11
E) 16

D

What causes the shape of the molecule shown above?
A) the configuration of the 2 p orbitals in the carbon atom
B) the configuration of the 1 s orbital in the carbon atom
C) the configuration of the sp hybrid orbitals of the electrons shared between the carbon and hydrogen atoms
D) the packing of the carbon and hydrogen atoms in a crystal lattice
E) hydrogen bonding configurations between the carbon and hydrogen atoms

C

In the methane molecule shown in the figure above, bonds have formed that include both the s orbital valence electrons of the hydrogen atoms and the p orbital valence electrons of the carbon. The electron orbitals in these bonds are said to be
A) double orbitals.
B) tetrahedral orbitals.
C) complex orbitals.
D) hybrid orbitals.
E) polar orbitals.

D

Which one of the atoms shown would be most likely to form a cation with a charge of +1?

[SEE IMAGE FOR CHOICES]

A

Which one of the atoms shown would be most likely to form an anion with a charge of -1?

[SEE IMAGE FOR CHOICES]

D

Which of the following pairs of atoms would be most likely to form a polar covalent bond?

[SEE IMAGE FOR CHOICES]

A

Which of the following pairs of atoms would be most likely to form an ionic bond?

[SEE IMAGE FOR CHOICES]

B

A group of molecular biologists is trying to synthesize a new artificial compound to mimic the effects of a known hormone that influences sexual behavior. They have turned to you for advice. Which of the following compounds is most likely to mimic the effects of the hormone?
A) a compound with the same number of carbon atoms as the hormone
B) a compound with the same molecular mass (measured in daltons) as the hormone
C) a compound with the same three-dimensional shape as part of the hormone
D) a compound with the same number of orbital electrons as the hormone
E) a compound with the same number of hydrogen and nitrogen atoms as the hormone

C

In the term trace element, the modifier trace means that
A) the element is required in very small amounts.
B) the element can be used as a label to trace atoms through an organism's metabolism.
C) the element is very rare on Earth.
D) the element enhances health but is not essential for the organism's long-term survival.
E) the element passes rapidly through the organism.

A

Compared with ³¹P, the radioactive isotope ³²P has
A) a different atomic number.
B) a different charge.
C) one more proton.
D) one more electron.
E) one more neutron.

E

The reactivity of an atom arises from
A) the average distance of the outermost electron shell from the nucleus.
B) the existence of unpaired electrons in the valence shell.
C) the sum of the potential energies of all the electron shells.
D) the potential energy of the valence shell.
E) the energy difference between the s and p orbitals.

B

Which statement is true of all atoms that are anions?
A) The atom has more electrons than protons.
B) The atom has more protons than electrons.
C) The atom has fewer protons than does a neutral atom of the same element.
D) The atom has more neutrons than protons.
E) The net charge is 1-.

A

Which of the following statements correctly describes any chemical reaction that has reached equilibrium?
A) The concentrations of products and reactants are equal.
B) The reaction is now irreversible.
C) Both forward and reverse reactions have halted.
D) The rates of the forward and reverse reactions are equal.
E) No reactants remain.

D

We can represent atoms by listing the number of protons, neutrons, and electrons: for example,
2p⁺; 2n⁰; 2e⁻ for helium. Which of the following represents the 18O isotope of oxygen?
A) 6p⁺, 8n⁰, 6e⁻
B) 8p⁺, 10n⁰, 8e⁻
C) 9p⁺, 9n⁰, 9e⁻
D) 7p⁺, 2n⁰, 9e⁻
E) 10p⁺, 8n⁰, 9e⁻

B

The atomic number of sulfur is 16. Sulfur combines with hydrogen by covalent bonding to form a compound, hydrogen sulfide. Based on the number of valence electrons in a sulfur atom, predict the molecular formula of the compound:
A) HS
B) HS₂
C) H₂S
D) H₃S₂
E) H₄S

C

What coefficients must be placed in the following blanks so that all atoms are accounted for in the products?
C₆H₁₂O₆ → ____ C₂H₆O + ____ CO₂
A) 1; 2
B) 3; 1
C) 1; 3
D) 1; 1
E) 2; 2

E

In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by
A) hydrogen bonds.
B) nonpolar covalent bonds.
C) polar covalent bonds.
D) ionic bonds.
E) van der Waals interactions.

C

The slight negative charge at one end of one water molecule is attracted to the slight positive charge of another water molecule. What is this attraction called?
A) a covalent bond
B) a hydrogen bond
C) an ionic bond
D) a hydrophilic bond
E) a van der Waals interaction

B

The partial negative charge in a molecule of water occurs because
A) the oxygen atom acquires an additional electron.
B) the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom nucleus than around the hydrogen atom nucleus.
C) the oxygen atom has two pairs of electrons in its valence shell that are not neutralized by hydrogen atoms.
D) the oxygen atom forms hybrid orbitals that distribute electrons unequally around the oxygen nucleus.
E) one of the hydrogen atoms donates an electron to the oxygen atom.

B

Sulfur is in the same column of the periodic table as oxygen, but has electronegativity similar to carbon. Compared to water molecules, molecules of H₂S
A) will ionize more readily.
B) will have greater cohesion to other molecules of H₂S.
C) will have a greater tendency to form hydrogen bonds with each other.
D) will have a higher capacity to absorb heat for the same change in temperature.
E) will not form hydrogen bonds with each other.

E

Water molecules are able to form hydrogen bonds with
A) compounds that have polar covalent bonds.
B) oils.
C) oxygen gas (O₂) molecules.
D) chloride ions.
E) any compound that is not soluble in water.

A

Which of the following effects is produced by the high surface tension of water?
A) Lakes don't freeze solid in winter, despite low temperatures.
B) A water strider can walk across the surface of a small pond.
C) Organisms resist temperature changes, although they give off heat due to chemical reactions.
D) Evaporation of sweat from the skin helps to keep people from overheating.
E) Water flows upward from the roots to the leaves in plants.

B

Which of the following takes place as an ice cube cools a drink?
A) Molecular collisions in the drink increase.
B) Kinetic energy in the drink decreases.
C) A calorie of heat energy is transferred from the ice to the water of the drink.
D) The specific heat of the water in the drink decreases.
E) Evaporation of the water in the drink increases.

B

A dietary Calorie equals 1 kilocalorie. Which of the following statements correctly defines 1 kilocalorie?
A) 1,000 calories, or the amount of heat required to raise the temperature of 1 g of water by 1,000°C
B) 100 calories, or the amount of heat required to raise the temperature of 100 g of water by 1°C
C) 10,000 calories, or the amount of heat required to raise the temperature of 1 kg of water by 1°F
D) 1,000 calories, or the amount of heat required to raise the temperature of 1 kg of water by 1°C
E) 1,000 calories, or the amount of heat required to raise the temperature of 100 g of water by 100°C

D

The nutritional information on a cereal box shows that one serving of a dry cereal has 200 kilocalories. If one were to burn one serving of the cereal, the amount of heat given off would be sufficient to raise the temperature of 20 kg of water how many degrees Celsius?
A) 0.2°C
B) 1.0°C
C) 2.0°C
D) 10.0°C
E) 20.0°C

D

Liquid water's high specific heat is mainly a consequence of the
A) small size of the water molecules.
B) high specific heat of oxygen and hydrogen atoms.
C) absorption and release of heat when hydrogen bonds break and form.
D) fact that water is a poor heat conductor.
E) higher density of liquid water than solid water (ice).

C

Which type of bond must be broken for water to vaporize?
A) ionic bonds
B) both hydrogen bonds and ionic bonds
C) polar covalent bonds
D) hydrogen bonds
E) both polar covalent bonds and hydrogen bonds

D

Temperature usually increases when water condenses. Which behavior of water is most directly responsible for this phenomenon?
A) the change in density when it condenses to form a liquid or solid
B) reactions with other atmospheric compounds
C) the release of heat by the formation of hydrogen bonds
D) the release of heat by the breaking of hydrogen bonds
E) the high surface tension of water

C

Why does evaporation of water from a surface cause cooling of the surface?
A) The breaking of bonds between water molecules absorbs heat.
B) The water molecules with the most heat energy evaporate more readily.
C) The solute molecules left behind absorb heat.
D) Water molecules absorb heat from the surface in order to acquire enough energy to evaporate.
E) The expansion of water vapor extracts heat from the surface.

B

Why does ice float in liquid water?
A) The high surface tension of liquid water keeps the ice on top.
B) The ionic bonds between the molecules in ice prevent the ice from sinking.
C) Ice always has air bubbles that keep it afloat.
D) Hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of liquid water.
E) The crystalline lattice of ice causes it to be denser than liquid water.

D

Hydrophobic substances such as vegetable oil are
A) nonpolar substances that repel water molecules.
B) nonpolar substances that have an attraction for water molecules.
C) polar substances that repel water molecules.
D) polar substances that have an affinity for water.
E) charged molecules that hydrogen-bond with water molecules.

A

One mole (mol) of glucose (molecular mass = 180 daltons) is
A) 180 × 10²³ molecules of glucose.
B) 1 kg of glucose dissolved in 1 L of solution.
C) the largest amount of glucose that can be dissolved in 1 L of solution.
D) 180 kilograms of glucose.
E) both 180 grams of glucose and 6.02 × 10²³ molecules of glucose.

E

How many molecules of glucose (C₆H₁₂O₆ molecular mass = 180 daltons) would be present in 90 grams of glucose?
A) 90 × 10²³
B) (6.02/180) × 10²³
C) (6.02/90) × 10²³
D) (90 x 6.02) × 10²³
E) (90/180) × 6.02 × 10²³

E

How many molecules of glycerol (C₃H₈O₃; molecular mass = 92) would be present in 1 L of a 1 M glycerol solution?
A) 1 × 10⁶
B) 14 × 6.02 × 10²³
C) 92 × 6.02 × 10²³
D) 6.02 × 10²⁶
E) 6.02 × 10²³

E

When an ionic compound such as sodium chloride (NaCl) is placed in water, the component atoms of the NaCl crystal dissociate into individual sodium ions (Na⁺) and chloride ions (Cl⁻). In contrast, the atoms of covalently bonded molecules (e.g., glucose, sucrose, glycerol) do not generally dissociate when placed in aqueous solution. Which of the following solutions would be expected to contain the greatest number of solute particles (molecules or ions)?
A) 1 L of 0.5 M NaCl
B) 1 L of 0.5 M glucose
C) 1 L of 1.0 M NaCl
D) 1 L of 1.0 M glucose
E) 1 L of 1.0 M NaCl and 1 L of 1.0 M glucose will contain equal numbers of solute particles.

C

The molar mass of glucose is 180 g/mol. Which of the following procedures should you carry out to make a 1 M solution of glucose?
A) Dissolve 1 g of glucose in 1 L of water.
B) Dissolve 180 g of glucose in 1 L of water.
C) Dissolve 180 g of glucose in 180 g of water.
D) Dissolve 180 milligrams (mg) of glucose in 1 L of water.
E) Dissolve 180 g of glucose in 0.8 L of water, and then add more water until the total volume of the solution is 1 L.

E

The molar mass of glucose (C₆H₁₂O₆) is 180 g/mol. Which of the following procedures should you carry out to make a 0.5 M solution of glucose?
A) Dissolve 0.5 g of glucose in a small volume of water, and then add more water until the total volume of solution is 1 L.
B) Dissolve 90 g of glucose in a small volume of water, and then add more water until the total volume of the solution is 1 L.
C) Dissolve 180 g of glucose in a small volume of water, and then add more water until the total volume of the solution is 1 L.
D) Dissolve 0.5 g of glucose in 1 L of water.
E) Dissolve 180 g of glucose in 0.5 L of water.

B

You have a freshly prepared 0.1 M solution of glucose in water. Each liter of this solution contains how many glucose molecules?
A) 6.02 × 10²³
B) 3.01 × 10²³
C) 6.02 × 10²⁴
D) 12.04 × 10²³
E) 6.02 × 10²²

E

The molecular weight of water is 18 daltons. What is the molarity of 1 liter of pure water? (Hint: What is the mass of 1 liter of pure water?)
A) 55.6 M
B) 18 M
C) 37 M
D) 0.66 M
E) 1.0 M

A

You have a freshly prepared 1 M solution of glucose in water. You carefully pour out a 100 mL sample of that solution. How many glucose molecules are included in that 100 mL sample?
A) 6.02 × 10²³
B) 3.01 × 10²³
C) 6.02 × 10²⁴
D) 12.04 × 10²³
E) 6.02 × 10²²

E

A strong acid like HCl
A) ionizes completely in an aqueous solution.
B) increases the pH when added to an aqueous solution.
C) reacts with strong bases to create a buffered solution.
D) is a strong buffer at low pH.
E) both ionizes completely in aqueous solutions and is a strong buffer at low pH.

A

Which of the following ionizes completely in solution and is considered to be a strong base (alkali)?
A) NaCl
B) HCl
C) NH₃
D) H₂CO₃
E) NaOH

E

A 0.01 M solution of a substance has a pH of 2. What can you conclude about this substance?
A) It is a strong acid that ionizes completely in water.
B) It is a strong base that ionizes completely in water.
C) It is a weak acid.
D) It is a weak base.
E) It is neither an acid nor a base.

A

A given solution contains 0.0001(10⁻⁴) moles of hydrogen ions [H⁺] per liter. Which of the following best describes this solution?
A) acidic: will accept H⁺ from both strong and weak acids
B) basic: will accept H⁺ from both strong and weak acids
C) acidic: will give H⁺ to weak acids, but accept H+ from strong acids
D) basic: will give H⁺ to weak acids, but accept H⁺ from weak acids
E) acidic: will give H⁺ to both strong and weak acids

C

A solution contains 0.0000001(10⁻⁷) moles of hydroxyl ions [OH⁻] per liter. Which of the following best describes this solution?
A) acidic: H⁺ acceptor
B) basic: H⁺ acceptor
C) acidic: H⁺ donor
D) basic: H⁺ donor
E) neutral

E

What is the pH of a solution with a hydroxyl ion [OH⁻] concentration of 10⁻¹² M?
A) pH 2
B) pH 4
C) pH 10
D) pH 12
E) pH 14

A

What is the pH of a 1 millimolar NaOH solution?
A) pH 3
B) pH 8
C) pH 9
D) pH 10
E) pH 11

E

Which of the following solutions would require the greatest amount of base to be added to bring the solution to neutral pH?
A) gastric juice at pH 2
B) vinegar at pH 3
C) tomato juice at pH 4
D) black coffee at pH 5
E) household bleach at pH 12

A

What is the hydrogen ion [H⁺] concentration of a solution of pH 8?
A) 8 M
B) 8 x 10⁻⁶ M
C) 0.01 M
D) 10⁻⁸ M
E) 10⁻⁶ M

D

If the pH of a solution is decreased from 9 to 8, it means that the
A) concentration of H⁺ has decreased to one-tenth (1/10) what it was at pH 9.
B) concentration of H⁺ has increased tenfold (10X) compared to what it was at pH 9.
C) concentration of OH⁻ has increased tenfold (10X) compared to what it was at pH 9.
D) concentration of OH⁻ has decreased to one-tenth (1/10) what it was at pH 9.
E) concentration of H⁺ has increased tenfold (10X) and the concentration of OH⁻ has decreased to one-tenth (1/10) what they were at pH 9.

E

If the pH of a solution is increased from pH 5 to pH 7, it means that the
A) concentration of H⁺ is twice (2X) what it was at pH 5.
B) concentration of H⁺ is one-half (1/2) what it was at pH 5.
C) concentration of OH⁻ is 100 times greater than what it was at pH 5.
D) concentration of OH⁻ is one-hundredth (0.01X) what it was at pH 5.
E) concentration of H⁺ is 100 times greater and the concentration of OH⁻ is one-hundredth what they were at pH 5.

C

One liter of a solution of pH 2 has how many more hydrogen ions (H⁺) than 1 L of a solution of pH 6?
A) 4 times more
B) 16 times more
C) 40,000 times more
D) 10,000 times more
E) 100,000 times more

D

One liter of a solution of pH 9 has how many more hydroxyl ions (OH⁻) than 1 L of a solution of pH 4?
A) 5 times more
B) 32 times more
C) 50,000 times more
D) 10,000 times more
E) 100,000 times more

E

Which of the following statements is true about buffer solutions?
A) They maintain a constant pH when bases are added to them but not when acids are added to them.
B) They maintain a constant pH when acids are added to them but not when bases are added to them.
C) They maintain a relatively constant pH of approximately 7 when either acids or bases are added to them.
D) They maintain a relatively constant pH when either acids or bases are added to them.
E) They are found only in living systems and biological fluids.

D

Buffers are substances that help resist shifts in pH by
A) releasing H⁺ to a solution when acids are added.
B) donating H⁺ to a solution when bases are added.
C) releasing OH⁻ to a solution when bases are added.
D) accepting H⁺ from a solution when acids are added.
E) both donating H⁺ to a solution when bases are added, and accepting H⁺ when acids are added.

E

One of the buffers that contribute to pH stability in human blood is carbonic acid (H₂CO₃). Carbonic acid is a weak acid that dissociates into a bicarbonate ion (HCO₃⁻) and a hydrogen ion (H⁺). Thus,

H₂CO₃ ↔ HCO₃⁻ + H⁺

If the pH of the blood drops, one would expect
A) a decrease in the concentration of H₂CO₃ and an increase in the concentration of HCO₃⁻.
B) the concentration of hydroxide ion (OH⁻) to increase.
C) the concentration of bicarbonate ion (HCO₃⁻) to increase.
D) the HCO₃⁻ to act as a base and remove excess H⁺ with the formation of H₂CO₃.
E) the HCO₃⁻ to act as an acid and remove excess H⁺ with the formation of H₂CO₃.

D

One of the buffers that contribute to pH stability in human blood is carbonic acid (H₂CO₃). Carbonic acid is a weak acid that, when placed in an aqueous solution, dissociates into a bicarbonate ion (HCO₃⁻ and a hydrogen ion (H⁺). Thus,

H₂CO₃ ↔ HCO₃⁻ + H⁺

If the pH of the blood increases, one would expect
A) a decrease in the concentration of H₂CO₃ and an increase in the concentration of HCO₃⁻.
B) an increase in the concentration of H₂CO₃ and a decrease in the concentration of HCO₃⁻.
C) a decrease in the concentration of HCO₃⁻ and an increase in the concentration of H⁺.
D) an increase in the concentration of HCO₃⁻ and a decrease in the concentration of OH⁻.
E) a decrease in the concentration of HCO₃⁻ and an increase in the concentration of both HH₂CO₃ and H⁺.

A

Assume that acid rain has lowered the pH of a particular lake to pH 4.0. What is the hydroxyl ion concentration of this lake?
A) 1 × 10⁻¹⁰ mol of hydroxyl ion per liter of lake water
B) 1 × 10⁻⁴ mol of hydroxyl ion per liter of lake water
C) 10.0 M with regard to hydroxyl ion concentration
D) 4.0 M with regard to hydroxyl ion concentration
E) 1 × 10⁻⁴ mol of hydroxyl ion per liter of lake water and 4.0 M with regard to hydrogen ion concentration

A

Research indicates that acid precipitation can damage living organisms by
A) buffering aquatic systems such as lakes and streams.
B) decreasing the H⁺ concentration of lakes and streams.
C) increasing the OH⁻ concentration of lakes and streams.
D) washing away certain mineral ions that help buffer soil solution and are essential nutrients for plant growth.
E) both decreasing the H⁺ concentration of lakes and streams and increasing the OH⁻ concentration of lakes and streams.

D

Consider two solutions: solution X has a pH of 4; solution Y has a pH of 7. From this information, we can reasonably conclude that
A) solution Y has no free hydrogen ions (H⁺).
B) the concentration of hydrogen ions in solution X is 30 times as great as the concentration of hydrogen ions in solution Y.
C) the concentration of hydrogen ions in solution Y is 1,000 times as great as the concentration of hydrogen ions in solution X.
D) the concentration of hydrogen ions in solution X is 3 times as great as the concentration of hydrogen ions in solution Y.
E) the concentration of hydrogen ions in solution X is 1,000 times as great as the concentration of hydrogen ions in solution Y.

E

If a solution has a pH of 7, this means that
A) there are no H⁺ ions in the water.
B) this is a solution of pure water.
C) the concentration of H⁺ ions in the water equals the concentration of OH⁻ ions in the water.
D) this is a solution of pure water, and the concentration of H⁺ ions in the water is 10⁻⁷ M.
E) this is a solution of pure water, and the concentration of H⁺ ions equals the concentration of OH⁻ ions in the water.

C

Carbon dioxide (CO₂) is readily soluble in water, according to the equation CO₂ + H₂O ↔ H₂CO₃. Carbonic acid (H₂CO₃) is a weak acid. Respiring cells release CO₂ into the bloodstream. What will be the effect on pH of blood as that blood first comes in contact with respiring cells?
A) Blood pH will decrease slightly.
B) Blood pH will increase slightly.
C) Blood pH will remain unchanged.
D) Blood pH will first increase, then decrease as CO₂ combines with hemoglobin.
E) Blood pH will first decrease, then increase sharply as CO₂ combines with hemoglobin.

A

A beaker contains 100 mL of NaOH solution at pH = 13. A technician carefully pours into the beaker 10 mL of HCl at pH = 1. Which of the following statements correctly describes the results of this mixing?
A) The concentration of Na⁺ ion rises.
B) The concentration of Cl⁻ ion will be 0.1 M.
C) The concentration of undissociated H₂O molecules remains unchanged.
D) The pH of the beaker's contents will be neutral.
E) The pH of the beaker's contents falls.

E

Equal volumes (5 mL) of vinegar from a freshly opened bottle are added to each of the following solutions. After complete mixing, which of the mixtures will have the highest pH?
A) 100 mL of pure water
B) 100 mL of freshly brewed coffee
C) 100 mL of household cleanser containing 0.5 M ammonia
D) 100 mL of freshly squeezed orange juice
E) 100 mL of tomato juice

C

Increased atmospheric CO₂ concentrations might have what effect on seawater?
A) Seawater will become more acidic, and bicarbonate concentrations will decrease.
B) Seawater will become more alkaline, and carbonate concentrations will decrease.
C) There will be no change in the pH of seawater, because carbonate will turn to bicarbonate.
D) Seawater will become more acidic, and carbonate concentrations will decrease.
E) Seawater will become more acidic, and carbonate concentrations will increase.

D

How would acidification of seawater affect marine organisms?
A) Acidification would increase dissolved carbonate concentrations and promote faster growth of corals and shell-building animals.
B) Acidification would decrease dissolved carbonate concentrations and promote faster growth of corals and shell-building animals.
C) Acidification would increase dissolved carbonate concentrations and hinder growth of corals and shell-building animals.
D) Acidification would decrease dissolved carbonate concentrations and hinder growth of corals and shell-building animals.
E) Acidification would increase dissolved bicarbonate concentrations, and cause increased calcification of corals and shellfish.

D

One idea to mitigate the effects of burning fossil fuels on atmospheric CO₂ concentrations is to pipe liquid CO₂ into the ocean at depths of 2,500 feet or greater. At the high pressures at such depths, CO₂ is heavier than water. What potential effects might result from implementing such a scheme?
A) increased photosynthetic carbon fixation because of the increased dissolved carbon dioxide in the deep water
B) increased carbonate concentrations in the deep waters
C) reduced growth of corals from a change in the carbonate—bicarbonate equilibrium
D) no effect because carbon dioxide is not soluble in water
E) both increased acidity of the deep waters and changes in the growth of bottom-dwelling organisms with calcium carbonate shells

E

If the cytoplasm of a cell is at pH 7, and the mitochondrial matrix is at pH 8, this means that
A) the concentration of H⁺ ions is tenfold higher in the cytoplasm than in the mitochondrial matrix.
B) the concentration of H⁺ ions is tenfold higher in the mitochondrial matrix than in the cytoplasm.
C) the concentration of H⁺ ions in the cytoplasm is 7/8 the concentration in the mitochondrial matrix.
D) the mitochondrial matrix is more acidic than the cytoplasm.
E) the concentration of H⁺ ions in the cytoplasm is 8/7 the concentration in the mitochondrial matrix.

A

Based on your knowledge of the polarity of water molecules, the solute molecule depicted here is most likely
A) positively charged.
B) negatively charged.
C) without charge.
D) hydrophobic.
E) nonpolar.

A

How many grams would be equal to 1 mol of the compound shown in the figure above?
(carbon = 12, oxygen = 16, hydrogen = 1)
A) 29
B) 30
C) 60
D) 150
E) 342

C

How many grams of the compound in the figure above would be required to make 1 L of a 0.5 M solution?
(carbon = 12, oxygen = 16, hydrogen = 1)
A) 29
B) 30
C) 60
D) 150
E) 342

B

How many grams of the compound in the figure above would be required to make 2.5 L of a 1 M solution?
(carbon = 12, oxygen = 16, hydrogen = 1)
A) 29
B) 30
C) 60
D) 150
E) 342

D

A small birthday candle is weighed, then lighted and placed beneath a metal can containing 100 mL of water. Careful records are kept as the temperature of the water rises. Data from this experiment are shown on the graph. What amount of heat energy is released in the burning of candle wax?
A) 0.5 kilocalories per gram of wax burned
B) 5 kilocalories per gram of wax burned
C) 10 kilocalories per gram of wax burned
D) 20 kilocalories per gram of wax burned
E) 50 kilocalories per gram of wax burned

A

Identical heat lamps are arranged to shine on identical containers of water and methanol (wood alcohol), so that each liquid absorbs the same amount of energy minute by minute. The covalent bonds of methanol molecules are nonpolar, so there are no hydrogen bonds among methanol molecules. Which of the following graphs correctly describes what will happen to the temperature of the water and the methanol?

[SEE IMAGE FOR CHOICES]

B

Which of these molecules would be soluble in water?

B

Carbon dioxide (CO₂) is readily soluble in water, according to the equation CO₂ + H₂O ↔ H₂CO₃. Carbonic acid (H₂CO₃) is a weak acid. If CO₂ is bubbled into a beaker containing pure, freshly distilled water, which of the following graphs correctly describes the results?

B

You have two beakers. One contains pure water, the other contains pure methanol (wood alcohol). The covalent bonds of methanol molecules are nonpolar, so there are no hydrogen bonds among methanol molecules. You pour crystals of table salt (NaCl) into each beaker. Predict what will happen.
A) Equal amounts of NaCl crystals will dissolve in both water and methanol.
B) NaCl crystals will NOT dissolve in either water or methanol.
C) NaCl crystals will dissolve readily in water but will not dissolve in methanol.
D) NaCl crystals will dissolve readily in methanol but will not dissolve in water.
E) When the first crystals of NaCl are added to water or to methanol, they will not dissolve; but as more crystals are added, the crystals will begin to dissolve faster and faster.

C

You have two beakers. One contains a solution of HCl at pH = 1.0. The other contains a solution of NaOH at pH = 13. Into a third beaker, you slowly and cautiously pour 20 mL of the HCl and 20 mL of the NaOH. After complete stirring, the pH of the mixture will be
A) 2.0.
B) 12.0.
C) 7.0.
D) 5.0.
E) 9.0.

C

Many mammals control their body temperature by sweating. Which property of water is most directly responsible for the ability of sweat to lower body temperature?
A) water's change in density when it condenses
B) water's ability to dissolve molecules in the air
C) the release of heat by the formation of hydrogen bonds
D) the absorption of heat by the breaking of hydrogen bonds
E) water's high surface tension

D

The bonds that are broken when water vaporizes are
A) ionic bonds.
B) hydrogen bonds between water molecules.
C) covalent bonds between atoms within water molecules.
D) polar covalent bonds.
E) nonpolar covalent bonds.

B

Which of the following is a hydrophobic material?
A) paper
B) table salt
C) wax
D) sugar
E) pasta

C

We can be sure that a mole of table sugar and a mole of vitamin C are equal in their
A) mass in daltons.
B) mass in grams.
C) volume.
D) number of atoms.
E) number of molecules.

E

Measurements show that the pH of a particular lake is 4.0. What is the hydrogen ion concentration of the lake?
A) 4.0 M
B) 10⁻¹⁰ M
C) 10⁻⁴ M
D) 10⁴ M
E) 4%

C

Measurements show that the pH of a particular lake is 4.0. What is the hydroxide ion concentration of the lake?
A) 10⁻¹⁰ M
B) 10⁻⁴ M
C) 10⁻⁷ M
D) 10⁻¹⁴ M
E) 10 M

A

A slice of pizza has 500 kcal. If we could burn the pizza and use all the heat to warm a 50-L container of cold water, what would be the approximate increase in the temperature of the water? (Note: A liter of cold water weighs about 1 kg.)
A) 50°C
B) 5°C
C) 1°C
D) 100°C
E) 10°C

E

How many grams of acetic acid (C₂H₄O₂) would you use to make 10 L of a 0.1 M aqueous solution of acetic acid? (Note: The atomic masses, in daltons, are approximately 12 for carbon, 1 for hydrogen, and 16 for oxygen.)
A) 10 g
B) 0.1 g
C) 6.0 g
D) 60 g
E) 0.6 g

D

The element present in all organic molecules is
A) hydrogen.
B) oxygen.
C) carbon.
D) nitrogen.
E) phosphorus.

C

The complexity and variety of organic molecules is due to
A) the chemical versatility of carbon atoms.
B) the variety of rare elements in organic molecules.
C) the fact that they can be synthesized only in living organisms.
D) their interaction with water.
E) their tremendously large sizes.

A

The experimental approach taken in current biological investigations presumes that
A) simple organic compounds can be synthesized in the laboratory from inorganic precursors, but complex organic compounds like carbohydrates and proteins can only be synthesized by living organisms.
B) a life force ultimately controls the activities of living organisms and this life force cannot be studied by physical or chemical methods.
C) although a life force, or vitalism, exists in living organisms, this life force cannot be studied by physical or chemical methods.
D) living organisms are composed of the same elements present in nonliving things, plus a few special trace elements found only in living organisms or their products.
E) living organisms can be understood in terms of the same physical and chemical laws that can be used to explain all natural phenomena.

E

Differences among organisms are caused by
A) large differences in elemental composition from organism to organism.
B) differences in the types and relative amounts of organic molecules synthesized by each organism.
C) differences in the elements that bond with carbon in each organism.
D) differences in the sizes of the organic molecules in each organism.
E) differences in inorganic compounds present in each organism.

B

Which of the following people was the first to synthesize an organic compound, urea, from inorganic starting materials?
A) Stanley Miller
B) Jakob Berzelius
C) Friedrich Wohler
D) Hermann Kolbe
E) August Kekulé

C

Stanley Miller's 1953 experiments proved that
A) life arose on Earth from simple inorganic molecules.
B) organic molecules can be synthesized abiotically under conditions that may have existed on early Earth.
C) life arose on Earth from simple organic molecules, with energy from lightning and volcanoes.
D) the conditions on early Earth were conducive to the origin of life.
E) the conditions on early Earth were conducive to the abiotic synthesis of organic molecules.

B

Hermann Kolbe's synthesis of an organic compound, acetic acid, from inorganic substances that had been prepared directly from pure elements was a significant milestone for what reason?
A) It solved an industrial shortage of acetic acid.
B) It proved that organic compounds could be synthesized from inorganic compounds.
C) It disproved the concept of vitalism.
D) It showed that life originated from simple inorganic chemicals.
E) It proved that organic compounds could be synthesized from inorganic compounds and disproved the concept of vitalism.

E

Stanley Miller's 1953 experiments assumed that early Earth's atmosphere contained
A) hydrogen cyanide, formaldehyde, hydrogen gas, and water vapor.
B) ammonia, methane, hydrogen gas, and water vapor.
C) ammonia, methane, oxygen gas, and water vapor.
D) amino acids, methane, hydrogen cyanide, and water vapor.
E) methane, formaldehyde, ammonia, and carbon dioxide.

B

When Stanley Miller applied heat and electrical sparks to a mixture of simple inorganic compounds such as methane, hydrogen gas, ammonia, and water vapor, what compounds were produced?
A) mostly amino acids
B) only simple organic compounds such as formaldehyde and cyanide
C) mostly hydrocarbons
D) only simple inorganic compounds
E) both simple organic compounds and more complex organic compounds such as amino acids and hydrocarbons

E

How many electron pairs does carbon share in order to complete its valence shell?
A) 1
B) 2
C) 3
D) 4
E) 8

D

A carbon atom is most likely to form what kind of bond(s) with other atoms?
A) ionic
B) hydrogen
C) covalent
D) covalent bonds and hydrogen bonds
E) ionic bonds, covalent bonds, and hydrogen bonds

C

Which of the following statements best describes the carbon atoms present in a seed-eating bird?
A) They were incorporated into organic molecules by plants.
B) They were processed into sugars through photosynthesis.
C) They are ultimately derived from carbon dioxide.
D) They were incorporated into organic molecules by plants, and they are ultimately derived from carbon dioxide.
E) They were incorporated into organic molecules by plants, they were processed into sugars through photosynthesis, and they are ultimately derived from carbon dioxide.

E

Which of the following statements best describes the carbon atoms present in a seed-eating bird?
A) Inorganic carbon atoms in the seeds were incorporated into organic molecules by the bird.
B) The carbon atoms ultimately came from the soil.
C) The carbon atoms are ultimately derived from coal.
D) The carbon atoms ultimately came from carbon dioxide incorporated into sugars through photosynthesis.
E) The carbon atoms ultimately came from simple organic compounds that formed abiotically from inorganic carbon, hydrogen, oxygen, and nitrogen atoms.

D

Why are hydrocarbons insoluble in water?
A) The majority of their bonds are polar covalent carbon-to-hydrogen linkages.
B) The majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages.
C) They are hydrophilic.
D) They exhibit considerable molecular complexity and diversity.
E) They are lighter than water.

B

How many structural isomers are possible for a substance having the molecular formula C₄H₁₀?
A) 1
B) 2
C) 4
D) 3
E) 11

B

Which of the following statements correctly describes cis-trans isomers?
A) They have variations in arrangement around a double bond.
B) They have an asymmetric carbon that makes them mirror images.
C) They have the same chemical properties.
D) They have different molecular formulas.
E) Their atoms and bonds are arranged in different sequences.

A

Research indicates that ibuprofen, a drug used to relieve inflammation and pain, is a mixture of two enantiomers; that is, molecules that
A) have identical chemical formulas but differ in the branching of their carbon skeletons.
B) are mirror images of one another.
C) exist in either linear chain or ring forms.
D) differ in the location of their double bonds.
E) differ in the arrangement of atoms around their double bonds.

B

What determines whether a carbon atom's covalent bonds to other atoms are in a tetrahedral configuration or a planar configuration?
A) the presence or absence of bonds with oxygen atoms
B) the presence or absence of double bonds between the carbon atom and other atoms
C) the polarity of the covalent bonds between carbon and other atoms
D) the presence or absence of bonds with nitrogen atoms
E) the solvent that the organic molecule is dissolved in

B

Compared to a hydrocarbon chain where all the carbon atoms are linked by single bonds, a hydrocarbon chain with the same number of carbon atoms, but with one or more double bonds, will
A) be more flexible in structure.
B) be more constrained in structure.
C) be more polar.
D) have more hydrogen atoms.
E) have fewer structurally distinct isomers.

B

Organic molecules with only hydrogens and five carbon atoms can have different structures in all of the following ways except
A) by branching of the carbon skeleton.
B) by varying the number of double bonds between carbon atoms.
C) by varying the position of double bonds between carbon atoms.
D) by forming a ring.
E) by forming enantiomers.

E

A compound contains hydroxyl groups as its predominant functional group. Which of the following statements is true concerning this compound?
A) It lacks an asymmetric carbon, and it is probably a fat or lipid.
B) It should dissolve in water.
C) It should dissolve in a nonpolar solvent.
D) It won't form hydrogen bonds with water.
E) It is hydrophobic.

B

Which of the following is a false statement concerning amino groups?
A) They are basic in pH.
B) They are found in amino acids.
C) They contain nitrogen.
D) They are nonpolar.
E) They are components of urea.

D

Which two functional groups are always found in amino acids?
A) ketone and methyl
B) carbonyl and amino
C) carboxyl and amino
D) amino and sulfhydryl
E) hydroxyl and carboxyl

C

Amino acids are acids because they always possess which functional group?
A) amino
B) carbonyl
C) carboxyl
D) phosphate
E) hydroxyl

C

A carbon skeleton is covalently bonded to both an amino group and a carboxyl group. When placed in water it
A) would function only as an acid because of the carboxyl group.
B) would function only as a base because of the amino group.
C) would function as neither an acid nor a base.
D) would function as both an acid and a base.
E) is impossible to determine how it would function.

D

Which functional groups can act as acids?
A) amino and sulfhydryl
B) carbonyl and carboxyl
C) carboxyl and phosphate
D) hydroxyl and aldehyde
E) ketone and amino

C

Testosterone and estradiol are
A) soluble in water.
B) structural isomers of each other.
C) proteins.
D) lipids.
E) enantiomers of each other.

B

Testosterone and estradiol are male and female sex hormones, respectively, in many vertebrates. In what way(s) do these molecules differ from each other?
A) Testosterone and estradiol are structural isomers but have the same molecular formula.
B) Testosterone and estradiol are cis-trans isomers but have the same molecular formula.
C) Testosterone and estradiol have different functional groups attached to the same carbon skeleton.
D) Testosterone and estradiol have distinctly different chemical structures, with one including four fused rings of carbon atoms, while the other has three rings.
E) Testosterone and estradiol are enantiomers of the same organic molecule.

C

Which of the following people used this apparatus to study the formation of organic compounds?
A) Stanley Miller
B) Jakob Berzelius
C) Friedrich Wohler
D) Hermann Kolbe
E) August Kekulé

A

The two molecules shown in the figure above are best described as
A) optical isomers.
B) enantiomers.
C) structural isomers.
D) cis-trans isomers.
E) chain length isomers.

C

The figure above shows the structures of glucose and fructose. These two molecules differ in the
A) number of carbon, hydrogen, and oxygen atoms.
B) types of carbon, hydrogen, and oxygen atoms.
C) arrangement of carbon, hydrogen, and oxygen atoms.
D) number of oxygen atoms joined to carbon atoms by double covalent bonds.
E) number of carbon, hydrogen, and oxygen atoms; the types of carbon, hydrogen, and oxygen atoms; and the arrangement of carbon, hydrogen, and oxygen atoms.

C

The figure above shows the structures of glucose and fructose. These two molecules are
A) geometric isotopes.
B) enantiomers.
C) cis-trans isomers.
D) structural isomers.
E) nonisotopic isomers.

D

The two molecules shown in the figure above are best described as
A) enantiomers.
B) radioactive isotopes.
C) structural isomers.
D) nonisotopic isomers.
E) cis-trans isomers.

E

Three or four of the following illustrations depict different structural isomers of the organic compound with molecular formula C₆H₁₄. For clarity, only the carbon skeletons are shown; hydrogen atoms that would be attached to the carbons have been omitted. Which one, if any, is NOT a structural isomer of this compound?

[SEE IMAGE FOR CHOICES]

C

Which of the pairs of molecular structures shown below depict enantiomers (enantiomeric forms) of the same molecule?

[SEE IMAGE FOR CHOICES]

D

Which of the pairs of molecular structures shown below do NOT depict enantiomers (enantiomeric forms) of the same molecule?

[SEE IMAGE FOR CHOICES]

C

Which pair of molecules shown below are not enantiomers of a single molecule?

[SEE IMAGE FOR CHOICES]

B

Thalidomide and L-dopa, shown below, are examples of pharmaceutical drugs that occur as enantiomers, or molecules that
A) have identical three-dimensional shapes.
B) are mirror images of one another.
C) are structural isomers.
D) are mirror images of one another and have the same biological activity.
E) are cis-trans isomers.

B

What is the name of the functional group shown in the figure above?
A) carbonyl
B) ketone
C) aldehyde
D) carboxyl
E) hydroxyl

D

Which of the structures illustrated above is an impossible covalently bonded molecule?
A) A
B) B
C) C
D) D
E) E

C

Which of the structures illustrated above contain(s) a carbonyl functional group?
A) A
B) C and D
C) C
D) D
E) C and E

D

In which of the structures illustrated above are the atoms bonded by ionic bonds?
A) A
B) B
C) C
D) C, D, and E only
E) none of the structures

E

Which of the structures illustrated above cannot form hydrogen bonds with water molecules?
A) A
B) B
C) C
D) D
E) E

B

Which functional group shown above is characteristic of alcohols?
A) A
B) B
C) C
D) D
E) E

A

Which functional group(s) shown above is (are) present in all amino acids?
A) A and B
B) B and D
C) C only
D) D only
E) C and D

E

Which of the groups shown above is a carbonyl functional group?
A) A
B) B
C) C
D) D
E) E

B

Which of the groups shown above is a functional group that helps stabilize proteins by forming covalent cross-links within or between protein molecules?
A) A
B) B
C) C
D) D
E) E

E

Which of the groups above is a carboxyl functional group?
A) A
B) B
C) C
D) D
E) E

C

Which of the groups above is an acidic functional group that can dissociate and release H⁺ into a solution?
A) A
B) B
C) C
D) D
E) E

C

Which of the groups above is a basic functional group that can accept H⁺ and become positively charged?
A) A
B) B
C) C
D) D
E) E

D

Which molecule shown above would have a positive charge in aqueous solution at pH 7?
A) A
B) B
C) C
D) D
E) E

E

Which molecule(s) shown above is (are) ionized in aqueous solution at pH 7?
A) A
B) B and D
C) D and E
D) D
E) E

A

Which molecules shown above contain a carbonyl group?
A) A and B
B) B and C
C) B, C, and D
D) D and E
E) E and A

B

Which molecule shown above has a carbonyl functional group in the form of a ketone?
A) A
B) B
C) C
D) D
E) E

C

Which molecule shown above has a carbonyl functional group in the form of an aldehyde?
A) A
B) B
C) C
D) D
E) E

B

Which molecule shown above contains a carboxyl group?
A) A
B) B
C) C
D) D
E) E

D

Which molecule shown above can increase the concentration of hydrogen ions in a solution and is therefore an organic acid?
A) A
B) B
C) C
D) D
E) E

D

Which molecule shown above can form a dimer linked by a covalent bond?
A) A
B) B
C) C
D) D
E) E

B

Which molecules shown above will form hydrogen bonds with water?
A) Only D will form hydrogen bonds with water.
B) All of these molecules will form hydrogen bonds with water.
C) None of these molecules will form hydrogen bonds with water.
D) All of these molecules except B will form hydrogen bonds with water.
E) Only C, D, and E will form hydrogen bonds with water.

D

Which molecule shown above contains an amino functional group, but is not an amino acid?
A) A
B) B
C) C
D) D
E) E

A

Which molecule shown above is a thiol?
A) A
B) B
C) C
D) D
E) E

B

Which molecule shown above contains a functional group that cells use to transfer energy between organic molecules?
A) A
B) B
C) C
D) D
E) E

D

Which molecule shown above can function as a base?
A) A
B) B
C) C
D) D
E) E

A

A chemist wishes to make an organic molecule less acidic. Which of the following functional groups should be added to the molecule in order to do so?
A) carboxyl
B) sulfhydryl
C) hydroxyl
D) amino
E) phosphate

D

Organic chemistry is currently defined as
A) the study of compounds made only by living cells.
B) the study of carbon compounds.
C) the study of vital forces.
D) the study of natural (as opposed to synthetic) compounds.
E) the study of hydrocarbons.

B

Which functional group is not present in this molecule?
A) carboxyl
B) sulfhydryl
C) hydroxyl
D) amino

B

Which chemical group is most likely to be responsible for an organic molecule behaving as a base?
A) hydroxyl
B) carbonyl
C) carboxyl
D) amino
E) phosphate

D

Which of the following hydrocarbons has a double bond in its carbon skeleton?
A) C₃H₈
B) C₂H₆
C) CH₄
D) C₂H₄
E) C₂H₂

D

Choose the term that correctly describes the relationship between these two sugar molecules:
A) structural isomers
B) cis-trans isomers
C) enantiomers
D) isotopes

A

Identify the asymmetric carbon in this molecule.
A) A
B) B
C) C
D) D
E) E

B

Which action could produce a carbonyl group?
A) the replacement of the OH of a carboxyl group with hydrogen
B) the addition of a thiol to a hydroxyl
C) the addition of a hydroxyl to a phosphate
D) the replacement of the nitrogen of an amine with oxygen
E) the addition of a sulfhydryl to a carboxyl

A

Humans and mice differ because
A) their cells have different small organic molecules.
B) their cells make different types of large biological molecules.
C) their cells make different types of lipids.
D) their cells have some differences in the sequence of nucleotides in their nucleic acids.
E) their cells make different types of proteins.

D

Molecules with which functional groups may form polymers via dehydration reactions?
A) hydroxyl groups
B) carbonyl groups
C) carboxyl groups
D) either carbonyl or carboxyl groups
E) either hydroxyl or carboxyl groups

E

Which of these molecules is not formed by dehydration reactions?
A) fatty acids
B) disaccharides
C) DNA
D) protein
E) amylose

A

In animal metabolism, most of the monomers released by digestion of food macromolecules are metabolized to provide energy. Only a small portion of these monomers are used for synthesis of new macromolecules. The net result is that
A) water is generated by animal metabolism.
B) water is consumed by animal metabolism.
C) the water consumed is exactly balanced by the water generated, to maintain homeostasis.
D) water is consumed during homeostasis, but water is generated during periods of growth.
E) water is generated during homeostasis, but water is consumed during periods of growth.

B

Which of these classes of biological molecules consist of both small molecules and macromolecular polymers?
A) lipids
B) carbohydrates
C) proteins
D) nucleic acids
E) lipids, carbohydrates, proteins, and nucleic acids all consist of only macromolecular polymers

B

Which of the following is not a polymer?
A) glucose
B) starch
C) cellulose
D) chitin
E) DNA

A

What is the chemical reaction mechanism by which cells make polymers from monomers?
A) phosphodiester linkages
B) hydrolysis
C) dehydration reactions
D) ionic bonding of monomers
E) the formation of disulfide bridges between monomers

C

How many molecules of water are needed to completely hydrolyze a polymer that is 11 monomers long?
A) 12
B) 11
C) 10
D) 9
E) 8

C

Which of the following best summarizes the relationship between dehydration reactions and hydrolysis?
A) Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers.
B) Dehydration reactions eliminate water from lipid membranes, and hydrolysis makes lipid membranes water permeable.
C) Dehydration reactions can occur only after hydrolysis.
D) Hydrolysis creates monomers, and dehydration reactions break down polymers.
E) Dehydration reactions ionize water molecules and add hydroxyl groups to polymers; hydrolysis reactions release hydroxyl groups from polymers.

A

Which of the following polymers contain nitrogen?
A) starch
B) glycogen
C) cellulose
D) chitin
E) amylopectin

D

The molecular formula for glucose is C₆H₁2O₆. What would be the molecular formula for a molecule made by linking three glucose molecules together by dehydration reactions?
A) C₁₈H₃₆O₁₈
B) C₁₈H₃₂O₁₆
C) C₆H₁₀O₅
D) C1₈H₁₀O₁₅
E) C₃H₆O₃

B

The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are the α form. Which of the following could amylase break down?
A) glycogen
B) cellulose
C) chitin
D) glycogen and chitin only
E) glycogen, cellulose, and chitin

A

On food packages, to what does the term insoluble fiber refer?
A) cellulose
B) polypeptides
C) starch
D) amylopectin
E) chitin

A

A molecule with the chemical formula C₆H₁₂O₆ is probably a
A) carbohydrate.
B) lipid.
C) monosaccharide
D) carbohydrate and lipid only.
E) carbohydrate and monosaccharide only.

E

Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified?
A) as a pentose
B) as a hexose
C) as a monosaccharide
D) as a disaccharide
E) as a polysaccharide

D

All of the following are polysaccharides except
A) lactose.
B) glycogen.
C) chitin.
D) cellulose.
E) amylopectin.

A

Which of the following is true of both starch and cellulose?
A) They are both polymers of glucose.
B) They are cis-trans isomers of each other.
C) They can both be digested by humans.
D) They are both used for energy storage in plants.
E) They are both structural components of the plant cell wall.

A

Which of the following is true of cellulose?
A) It is a polymer composed of enantiomers of glucose.
B) It is a storage polysaccharide for energy in plant cells.
C) It is digestible by bacteria in the human gut.
D) It is a major structural component of plant cell walls.
E) It is a polymer composed of enantiomers of glucose, it is a storage polysaccharide for energy in plant cells, it is digestible by bacteria in the human gut, and it is a major structural component of plant cell walls.

D

Humans can digest starch but not cellulose because
A) the monomer of starch is glucose, while the monomer of cellulose is galactose.
B) humans have enzymes that can hydrolyze the β glycosidic linkages of starch but not the α glycosidic linkages of cellulose.
C) humans have enzymes that can hydrolyze the α glycosidic linkages of starch but not the β glycosidic linkages of cellulose.
D) humans harbor starch-digesting bacteria in the digestive tract.
E) the monomer of starch is glucose, while the monomer of cellulose is glucose with a nitrogen-containing group.

C

Which of the following statements concerning saturated fats is not true?
A) They are more common in animals than in plants.
B) They have multiple double bonds in the carbon chains of their fatty acids.
C) They generally solidify at room temperature.
D) They contain more hydrogen than unsaturated fats having the same number of carbon atoms.
E) They are one of several factors that contribute to atherosclerosis.

B

A molecule with the formula C₁₈H3₆O₂ is probably a
A) carbohydrate.
B) fatty acid.
C) protein.
D) nucleic acid.
E) hydrocarbon.

B

Which of the following statements is true for the class of biological molecules known as lipids?
A) They are insoluble in water.
B) They are made from glycerol, fatty acids, and phosphate.
C) They contain less energy than proteins and carbohydrates.
D) They are made by dehydration reactions.
E) They contain nitrogen.

A

The label on a container of margarine lists "hydrogenated vegetable oil" as the major ingredient. What is the result of adding hydrogens to vegetable oil?
A) The hydrogenated vegetable oil has a lower melting point.
B) The hydrogenated vegetable oil stays solid at room temperature.
C) The hydrogenated vegetable oil has more "kinks" in the fatty acid chains.
D) The hydrogenated vegetable oil has fewer trans fatty acids.
E) The hydrogenated vegetable oil is less likely to clog arteries.

B

Which of the following is true regarding saturated fatty acids?
A) They are the predominant fatty acid in corn oil.
B) They have double bonds between carbon atoms of the fatty acids.
C) They are the principal molecules in lard and butter.
D) They are usually liquid at room temperature.
E) They are usually produced by plants.

C

Large organic molecules are usually assembled by polymerization of a few kinds of simple subunits. Which of the following is an exception to this statement?
A) a steroid
B) cellulose
C) DNA
D) an enzyme
E) a contractile protein

A

Which modifications of fatty acids will best keep triglycerides solid at warmer temperatures?
A) creating cis double bonds to the fatty acids
B) adding hydrogens to the fatty acids
C) creating trans double bonds to the fatty acids
D) adding hydrogens and trans double bonds to the fatty acids
E) adding cis double bonds and trans double bonds to the fatty acids

D

Why are human sex hormones considered to be lipids?
A) They are essential components of cell membranes.
B) They are not soluble in water.
C) They are made of fatty acids.
D) They are hydrophilic compounds.
E) They contribute to atherosclerosis.

B

All of the following contain amino acids except
A) hemoglobin.
B) cholesterol.
C) antibodies.
D) enzymes.
E) insulin.

B

The bonding of two amino acid molecules to form a larger molecule requires
A) the release of a water molecule.
B) the release of a carbon dioxide molecule.
C) the addition of a nitrogen atom.
D) the addition of a water molecule.
E) the release of a nitrous oxide molecule.

A

There are 20 different amino acids. What makes one amino acid different from another?
A) different side chains (R groups) attached to a carboxyl carbon
B) different side chains (R groups) attached to the amino groups
C) different side chains (R groups) attached to an α carbon
D) different structural and optical isomers
E) different asymmetric carbons

C

The bonding of two amino acid molecules to form a larger molecule requires which of the following?
A) removal of a water molecule
B) addition of a water molecule
C) formation of a glycosidic bond
D) formation of a hydrogen bond
E) both removal of a water molecule and formation of a hydrogen bond

A

Polysaccharides, triacylglycerides, and proteins are similar in that they
A) are synthesized from monomers by the process of hydrolysis.
B) are synthesized from subunits by dehydration reactions.
C) are synthesized as a result of peptide bond formation between monomers.
D) are decomposed into their subunits by dehydration reactions.
E) all contain nitrogen in their monomer building blocks.

B

Dehydration reactions are used in forming which of the following compounds?
A) triacylglycerides
B) polysaccharides
C) proteins
D) triacylglycerides and proteins only
E) triacylglycerides, polysaccharides, and proteins

E

Upon chemical analysis, a particular polypeptide was found to contain 100 amino acids. How many peptide bonds are present in this protein?
A) 101
B) 100
C) 99
D) 98
E) 97

C

What aspects of protein structure are stabilized or assisted by hydrogen bonds?
A) primary structure
B) secondary structure
C) tertiary structure
D) quaternary structure
E) secondary, tertiary, and quaternary structures, but not primary structure

E

How many different kinds of polypeptides, each composed of 12 amino acids, could be synthesized using the 20 common amino acids?
A) 4¹²
B) 12²⁰
C) 240
D) 20
E) 20¹²

E

Which bonds are created during the formation of the primary structure of a protein?
A) peptide bonds
B) hydrogen bonds
C) disulfide bonds
D) phosphodiester bonds
E) peptide bonds, hydrogen bonds, and disulfide bonds

A

What maintains the secondary structure of a protein?
A) peptide bonds
B) hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond
C) disulfide bonds
D) hydrophobic interactions
E) hydrogen bonds between the R groups

B

Which type of interaction stabilizes the α helix and the β pleated sheet structures of proteins?
A) hydrophobic interactions
B) disulfide bonds
C) ionic bonds
D) hydrogen bonds
E) peptide bonds

D

Which level of protein structure do the α helix and the β pleated sheet represent?
A) primary
B) secondary
C) tertiary
D) quaternary
E) primary, secondary, tertiary, and quaternary

B

The amino acids of the protein keratin are arranged predominantly in an α helix. This secondary structure is stabilized by
A) covalent bonds.
B) peptide bonds.
C) ionic bonds.
D) polar bonds.
E) hydrogen bonds.

E

The tertiary structure of a protein is the
A) bonding together of several polypeptide chains by weak bonds.
B) order in which amino acids are joined in a polypeptide chain.
C) unique three-dimensional shape of the fully folded polypeptide.
D) organization of a polypeptide chain into an α helix or β pleated sheet.
E) overall protein structure resulting from the aggregation of two or more polypeptide subunits.

C

What type of covalent bond between amino acid side chains (R groups) functions in maintaining a polypeptide's specific three-dimensional shape?
A) ionic bond
B) hydrophobic interaction
C) van der Waals interaction
D) disulfide bond
E) hydrogen bond

D

At which level of protein structure are interactions between the side chains (R groups) most important?
A) primary
B) secondary
C) tertiary
D) quaternary
E) all of the above

C

The R group or side chain of the amino acid serine is –CH₂–OH. The R group or side chain of the amino acid leucine is –CH₂–CH–(CH₃)₂. Where would you expect to find these amino acids in a globular protein in aqueous solution?
A) Serine would be in the interior, and leucine would be on the exterior of the globular protein.
B) Leucine would be in the interior, and serine would be on the exterior of the globular protein.
C) Both serine and leucine would be in the interior of the globular protein.
D) Both serine and leucine would be on the exterior of the globular protein.
E) Both serine and leucine would be in the interior and on the exterior of the globular protein.

B

Misfolding of polypeptides is a serious problem in cells. Which of the following diseases are associated with an accumulation of misfolded polypeptides?
A) Alzheimer's only
B) Parkinson's only
C) diabetes mellitus only
D) Alzheimer's and Parkinson's only
E) Alzheimer's, Parkinson's, and diabetes mellitus

D

Changing a single amino acid in a protein consisting of 325 amino acids would
A) alter the primary structure of the protein, but not its tertiary structure or function.
B) cause the tertiary structure of the protein to unfold.
C) always alter the biological activity or function of the protein.
D) always alter the primary structure of the protein and disrupt its biological activity.
E) always alter the primary structure of the protein, sometimes alter the tertiary structure of the protein, and affect its biological activity.

E

Normal hemoglobin is a tetramer, consisting of two molecules of β hemoglobin and two molecules of α hemoglobin. In sickle-cell disease, as a result of a single amino acid change, the mutant hemoglobin tetramers associate with each other and assemble into large fibers. Based on this information alone, we can conclude that sickle-cell hemoglobin exhibits
A) altered primary structure.
B) altered secondary structure.
C) altered tertiary structure.
D) altered quaternary structure.
E) altered primary structure and altered quaternary structure; the secondary and tertiary structures may or may not be altered.

E

What methods may be used to elucidate the structures of purified proteins?
A) X-ray crystallography
B) bioinformatics
C) analysis of amino acid sequence of small fragments
D) NMR spectroscopy
E) both X-ray crystallography and NMR spectroscopy

E

In a normal cellular protein, where would you expect to find a hydrophobic amino acid like valine?
A) in the interior of the folded protein, away from water
B) on the exterior surface of the protein, interacting with water
C) in the transmembrane portion interacting with lipid fatty acid chains
D) in the interior of the folded protein, away from water, or in a transmembrane portion interacting with lipid fatty acid chains
E) anywhere in the protein, with equal probability

D

Which of the following techniques uses the amino acid sequences of polypeptides to predict a protein's three-dimensional structure?
A) X-ray crystallography
B) bioinformatics
C) analysis of amino acid sequence of small fragments
D) NMR spectroscopy
E) high-speed centrifugation

B

If cells are grown in a medium containing radioactive ³⁵S, which of these molecules will be labeled?
A) phospholipids
B) nucleic acids
C) proteins
D) amylose
E) both proteins and nucleic acids

C

What is the term used for a protein molecule that assists in the proper folding of other proteins?
A) tertiary protein
B) chaperonin
C) enzyme protein
D) renaturing protein
E) denaturing protein

B

DNAase is an enzyme that catalyzes the hydrolysis of the covalent bonds that join nucleotides together. What would first happen to DNA molecules treated with DNAase?
A) The two strands of the double helix would separate.
B) The phosphodiester bonds between deoxyribose sugars would be broken.
C) The purines would be separated from the deoxyribose sugars.
D) The pyrimidines would be separated from the deoxyribose sugars.
E) All bases would be separated from the deoxyribose sugars.

B

Which of the following statements about the 5' end of a polynucleotide strand of DNA is correct?
A) The 5' end has a hydroxyl group attached to the number 5 carbon of ribose.
B) The 5' end has a phosphate group attached to the number 5 carbon of ribose.
C) The 5' end has phosphate attached to the number 5 carbon of the nitrogenous base.
D) The 5' end has a carboxyl group attached to the number 5 carbon of ribose.
E) The 5' end is the fifth position on one of the nitrogenous bases.

B

One of the primary functions of RNA molecules is to
A) transmit genetic information to offspring.
B) function in the synthesis of proteins.
C) make a copy of itself, thus ensuring genetic continuity.
D) act as a pattern or blueprint to form DNA.
E) form the genes of higher organisms.

B

If ¹⁴C-labeled uridine triphosphate is added to the growth medium of cells, what macromolecules will be labeled?
A) phospholipids
B) DNA
C) RNA
D) both DNA and RNA
E) proteins

C

Which of the following descriptions best fits the class of molecules known as nucleotides?
A) a nitrogenous base and a phosphate group
B) a nitrogenous base and a pentose sugar
C) a nitrogenous base, a phosphate group, and a pentose sugar
D) a phosphate group and an adenine or uracil
E) a pentose sugar and a purine or pyrimidine

C

Which of the following are nitrogenous bases of the pyrimidine type?
A) guanine and adenine
B) cytosine and uracil
C) thymine and guanine
D) ribose and deoxyribose
E) adenine and thymine

B

Which of the following are nitrogenous bases of the purine type?
A) cytosine and guanine
B) guanine and adenine
C) adenine and thymine
D) thymine and uracil
E) uracil and cytosine

B

If a DNA sample were composed of 10% thymine, what would be the percentage of guanine?
A) 10
B) 20
C) 40
D) 80
E) impossible to tell from the information given

C

A double-stranded DNA molecule contains a total of 120 purines and 120 pyrimidines. This DNA molecule could be composed of
A) 120 adenine and 120 uracil molecules.
B) 120 thymine and 120 adenine molecules.
C) 120 cytosine and 120 thymine molecules.
D) 120 adenine and 120 cytosine molecules.
E) 120 guanine and 120 thymine molecules.

B

The difference between the sugar in DNA and the sugar in RNA is that the sugar in DNA
A) is a six-carbon sugar and the sugar in RNA is a five-carbon sugar.
B) can form a double-stranded molecule.
C) is an aldehyde sugar and the sugar in RNA is a keto sugar.
D) is in the α configuration and the sugar in RNA is in the β configuration.
E) contains one less oxygen atom.

E

Which of the following statements best summarizes the differences between DNA and RNA?
A) DNA encodes hereditary information, whereas RNA does not.
B) The bases in DNA form base-paired duplexes, whereas the bases in RNA do not.
C) DNA nucleotides contain a different sugar than RNA nucleotides.
D) DNA contains the base uracil, whereas RNA contains the base thymine.
E) DNA encodes hereditary information, whereas RNA does not; the bases in DNA form base-paired duplexes, whereas the bases in RNA do not; and DNA nucleotides contain a different sugar than RNA nucleotides.

C

If one strand of a DNA molecule has the sequence of bases 5'ATTGCA3', the other complementary strand would have the sequence
A) 5'TAACGT3'.
B) 5'TGCAAT3'.
C) 5'UAACGU3'.
D) 3'UAACGU5'.
E) 5'UGCAAU3'.

B

What is the structural feature that allows DNA to replicate?
A) sugar-phosphate backbone
B) complementary pairing of the nitrogenous bases
C) disulfide bonding (bridging) of the two helixes
D) twisting of the molecule to form an α helix
E) three-component structure of the nucleotides

B

A new organism is discovered in the forests of Costa Rica. Scientists there determine that the polypeptide sequence of hemoglobin from the new organism has 72 amino acid differences from humans, 65 differences from a gibbon, 49 differences from a rat, and 5 differences from a frog. These data suggest that the new organism
A) is more closely related to humans than to frogs.
B) is more closely related to frogs than to humans.
C) evolved at about the same time as frogs, which is much earlier than primates and mammals.
D) is more closely related to humans than to rats.
E) is more closely related to frogs than to humans and also evolved at about the same time as frogs, which is much earlier than primates and mammals.

B

Which of the following is an example of hydrolysis?
A) the reaction of two monosaccharides, forming a disaccharide with the release of water
B) the synthesis of two amino acids, forming a peptide with the release of water
C) the reaction of a fat, forming glycerol and fatty acids with the release of water
D) the reaction of a fat, forming glycerol and fatty acids with the consumption of water
E) the synthesis of a nucleotide from a phosphate, a pentose sugar, and a nitrogenous base with the production of a molecule of water

D

If cells are grown in a medium containing radioactive ³²P-labeled phosphate, which of these molecules will be labeled?
A) phospholipids
B) nucleic acids
C) proteins
D) amylose
E) both phospholipids and nucleic acids

E

If cells are grown in a medium containing radioactive ¹⁵N, which of these molecules will be labeled?
A) fatty acids only
B) nucleic acids only
C) proteins only
D) amylase only
E) both proteins and nucleic acids

E

How will brief heating (to 95°C) affect macromolecular structures in aqueous solution?
A) DNA duplexes will unwind and separate.
B) Proteins will unfold (denature).
C) Starch will hydrolyze into monomeric sugars.
D) Proteins will hydrolyze into amino acids.
E) DNA duplexes will unwind and separate, and proteins will unfold (denature).

E

Which of the following is not a monomer/polymer pairing?
A) monosaccharide/polysaccharide
B) amino acid/protein
C) triglyceride/phospholipid bilayer
D) deoxyribonucleotide/DNA
E) ribonucleotide/RNA

C

If two molecules of the general type shown in Figure 5.1 were linked together, carbon-1 of one molecule to carbon-4 of the other, the single molecule that would result would be
A) maltose.
B) fructose.
C) glucose.
D) galactose.
E) sucrose.

A

Which of the following descriptors is true of the molecule shown in Figure 5.1?
A) hexose
B) fructose
C) glucose
D) hexose and fructose only
E) hexose and glucose only

E

Which of the following statements is true regarding the molecule illustrated in Figure 5.2?
A) It is a saturated fatty acid.
B) A diet rich in this molecule may contribute to atherosclerosis.
C) Molecules of this type are usually liquid at room temperature.
D) It is a saturated fatty acid and a diet rich in this molecule may contribute to atherosclerosis.
E) It is a saturated fatty acid, a diet rich in this molecule may contribute to atherosclerosis, and molecules of this type are usually liquid at room temperature.

D

Which of the following statements is true regarding the molecule illustrated in Figure 5.3?
A) It is a saturated fatty acid.
B) A diet rich in this molecule may contribute to atherosclerosis.
C) Molecules of this type are usually liquid at room temperature.
D) It is a saturated fatty acid and a diet rich in this molecule may contribute to atherosclerosis.
E) It is a saturated fatty acid, a diet rich in this molecule may contribute to atherosclerosis, and molecules of this type are usually liquid at room temperature.

C

The molecule shown in Figure 5.3 is a
A) polysaccharide.
B) polypeptide.
C) saturated fatty acid.
D) triacylglycerol.
E) unsaturated fatty acid.

E

What is the structure shown in Figure 5.4?
A) pentose molecule
B) fatty acid molecule
C) steroid molecule
D) oligosaccharide molecule
E) phospholipid molecule

C

Which of the following statements is/are true regarding the chemical reaction illustrated in Figure 5.5?
A) It is a hydrolysis reaction.
B) It results in a peptide bond.
C) It joins two fatty acids together.
D) It is a hydrolysis reaction and it results in a peptide bond.
E) It is a hydrolysis reaction, it results in a peptide bond, and it joins two fatty acids together.

B

At which bond would water need to be added to achieve hydrolysis of the peptide, back to its component amino acid?
A) A
B) B
C) C
D) D
E) E

C

Which bond is a peptide bond?
A) A
B) B
C) C
D) D
E) E

C

Which bond is closest to the amino terminus of the molecule?
A) A
B) B
C) C
D) D
E) E

A

The structure depicted in Figure 5.7 shows the
A) 1-4 linkage of the α glucose monomers of starch.
B) 1-4 linkage of the β glucose monomers of cellulose.
C) double-helical structure of a DNA molecule.
D) α helix secondary structure of a polypeptide.
E) β pleated sheet secondary structure of a polypeptide.

D

Which molecule has both hydrophilic and hydrophobic properties and would be found in plasma membranes?
A) 1
B) 5
C) 6
D) 12
E) 14

B

Which of the following combinations could be linked together to form a nucleotide?
A) 1, 2, and 11
B) 3, 7, and 8
C) 5, 9, and 10
D) 11, 12, and 13
E) 12, 14, and 15

D

Which of the following molecules contain(s) an aldehyde type of carbonyl functional group?
A) 1
B) 4
C) 8
D) 10
E) 1 and 4

E

Which molecule is glycerol?
A) 1
B) 6
C) 10
D) 14
E) 15

C

Which molecule is a saturated fatty acid?
A) 1
B) 5
C) 6
D) 8
E) 9

E

Which of the following molecules is a purine type of nitrogenous base?
A) 2
B) 3
C) 5
D) 12
E) 13

E

Which of the following molecules act as building blocks (monomers) of polypeptides?
A) 1, 4, and 6
B) 2, 7, and 8
C) 7, 8, and 13
D) 11, 12, and 13
E) 12, 13, and 15

B

Which of the following molecules is an amino acid with a hydrophobic R group or side chain?
A) 3
B) 7
C) 8
D) 12
E) 13

B

Which of the following molecules could be joined together by a peptide bond as a result of a dehydration reaction?
A) 2 and 3
B) 3 and 7
C) 7 and 8
D) 8 and 9
E) 12 and 13

C

A fat (or triacylglycerol) would be formed as a result of a dehydration reaction between
A) one molecule of 9 and three molecules of 10.
B) three molecules of 9 and one molecule of 10.
C) one molecule of 5 and three molecules of 9.
D) three molecules of 5 and one molecule of 9.
E) one molecule of 5 and three molecules of 10.

B

Which of the following molecules could be joined together by a phosphodiester type of covalent bond?
A) 3 and 4
B) 3 and 8
C) 6 and 15
D) 11 and 12
E) 11 and 13

D

Which of the following molecules is the pentose sugar found in RNA?
A) 1
B) 4
C) 6
D) 12
E) 13

D

Which of the following molecules contains a glycosidic linkage type of covalent bond?
A) 4
B) 6
C) 12
D) 13
E) 15

E

Which of the following molecules has a functional group that frequently forms covalent bonds that maintain the tertiary structure of a protein?
A) 2
B) 3
C) 7
D) 8
E) 9

A

Which of the following molecules consists of a hydrophilic "head" region and a hydrophobic "tail" region?
A) 2
B) 5
C) 7
D) 9
E) 11

B

Which of the following statements is false?
A) Molecules 1 and 4 could be joined together by a glycosidic linkage to form a disaccharide.
B) Molecules 9 and 10 could be joined together by ester bonds to form a triacylglycerol.
C) Molecules 2 and 7 could be joined together to form a short peptide.
D) Molecules 2, 7, and 8 could be joined together to form a short peptide.
E) Molecules 14 and 15 could be joined together to form a polypeptide.

E

Approximately 32 different monomeric carbohydrate subunits are found in various natural polysaccharides. Proteins are composed of 20 different amino acids. DNA and RNA are each synthesized from four nucleotides.

Among these biological polymers, which has the least structural variety?
A) polysaccharides
B) proteins
C) DNA
D) RNA

C

Which class of biological polymer has the greatest functional variety?
A) polysaccharides
B) proteins
C) DNA
D) RNA

B

Professor Jamey Marth at the University of California, Santa Barbara, identified 70 molecules that are used to build cellular macromolecules and structures. These include at least 34 saccharides, 8 nucleosides, and 20 amino acids. In theory, then, which class of biological polymer has the greatest information-coding capacity?
A) polysaccharides
B) proteins
C) DNA
D) RNA

A

Which of the following categories includes all others in the list?
A) monosaccharide
B) disaccharide
C) starch
D) carbohydrate
E) polysaccharide

D

The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are in the α form. Which of the following could amylase break down?
A) glycogen, starch, and amylopectin
B) glycogen and cellulose
C) cellulose and chitin
D) starch and chitin
E) starch, amylopectin, and cellulose

A

Which of the following statements concerning unsaturated fats is true?
A) They are more common in animals than in plants.
B) They have double bonds in the carbon chains of their fatty acids.
C) They generally solidify at room temperature.
D) They contain more hydrogen than do saturated fats having the same number of carbon atoms.
E) They have fewer fatty acid molecules per fat molecule.

B

The structural level of a protein least affected by a disruption in hydrogen bonding is the
A) primary level.
B) secondary level.
C) tertiary level.
D) quaternary level.
E) All structural levels are equally affected.

A

Enzymes that break down DNA catalyze the hydrolysis of the covalent bonds that join nucleotides together. What would happen to DNA molecules treated with these enzymes?
A) The two strands of the double helix would separate.
B) The phosphodiester linkages of the polynucleotide backbone would be broken.
C) The purines would be separated from the deoxyribose sugars.
D) The pyrimidines would be separated from the deoxyribose sugars.
E) All bases would be separated from the deoxyribose sugars.

B

The molecular formula for glucose is C₆H₁₂O₆. What would be the molecular formula for a polymer made by linking ten glucose molecules together by dehydration reactions?
A) C₆₀H₁₂₀O₆₀
B) C₆H₁₂O₆
C) C₆₀H₁₀₂O₅₁
D) C₆₀H₁₀₀O₅₀
E) C₆₀H₁₁₁O₅₁

C

Which of the following pairs of base sequences could form a short stretch of a normal double helix of DNA?
A) 5'-purine-pyrimidine-purine-pyrimidine-3' with 3'-purine-pyrimidine-purine-pyrimidine-5'
B) 5'-AGCT-3' with 5'-TCGA-3'
C) 5'-GCGC-3' with 5'-TATA-3'
D) 5'-ATGC-3' with 5'-GCAT-3'
E) All of these pairs are correct.

D