1) The smallest cell structure that would most likely be visible with a standard (not super- resolution) research-grade light microscope is a _____.
A) mitochondrion
B) microtubule

C) ribosome
D) microfilament

A

2) The advantage of light microscopy over electron microscopy is that _____.
A) light microscopy provides for higher magnification than electron microscopy

B) light microscopy provides for higher resolving power than electron microscopy

C) light microscopy allows one to view dynamic processes in living cells
D) light microscopy provides higher contrast than electron microscopy

C

3) In the fractionation of homogenized cells using centrifugation, the primary factor that determines whether a specific cellular component ends up in the supernatant or the pellet is the _____.
A) relative solubility of the component
B) size and weight of the component
C) percentage of carbohydrates in the component
D) presence or absence of lipids in the component

B

5) What technique would be most appropriate to use to observe the movements of condensed chromosomes during cell division?
A) standard light microscopy
B) scanning electron microscopy

C) transmission electron microscopy

A

7) All of the following are part of a prokaryotic cell EXCEPT _____.

A) a cell wall
B) a plasma membrane
C) ribosomes

D) an endoplasmic reticulum

D

9) Which of the following is a major difference between prokaryotic cells and eukaryotic cells?

A) Prokaryotes have cells while eukaryotes do not.
B) Eukaryotic cells have more intracellular organelles than prokaryotes.
C) Prokaryotes are not able to carry out aerobic respiration, relying instead on anaerobic metabolism.

D) Prokaryotes are generally larger than eukaryotes.

B

11) Prokaryotes are classified as belonging to two different domains. What are the domains?

A) Bacteria and Eukarya
B) Bacteria and Archaea
C) Archaea and Protista

D) Bacteria and Protista

B

12) Which structure is common to plant and animal cells?

A) chloroplast
B) central vacuole
C) mitochondrion

D) centriole

C

13) Which of the following is present in a prokaryotic cell?

A) mitochondrion
B) ribosome
C) chloroplast

D) ER

B

15) Which organelle or structure is absent in plant cells?

A) mitochondria
B) microtubules
C) centrosomes

D) peroxisomes

C

16) What is the function of the nuclear pore complex found in eukaryotes?
A) It regulates the movement of proteins and RNAs into and out of the nucleus.
B) It synthesizes the proteins required to copy DNA and make mRNA.
C) It selectively transports molecules out of the nucleus, but prevents all inbound molecules from entering the nucleus.
D) It assembles ribosomes from raw materials that are synthesized in the nucleus.

A

17) Which of the following macromolecules leaves the nucleus of a eukaryotic cell through pores in the nuclear membrane?
A) DNA
B) amino acids

C) mRNA
D) phospholipids

C

18) Which of the following statements correctly describes some aspect of protein secretion from prokaryotic cells?
A) Prokaryotes cannot secrete proteins because they lack an endomembrane system.
B) The mechanism of protein secretion in prokaryotes is probably the same as that in eukaryotes.

C) Proteins secreted by prokaryotes are synthesized on ribosomes bound to the cytoplasmic surface of the plasma membrane.

D) Prokaryotes cannot secrete proteins because they lack ribosomes.

C

19) Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules?
A) lipids
B) glycogen

C) proteins
D) nucleic acids

C

21) A cell with a predominance of free ribosomes is most likely _____.

A) primarily producing proteins for secretion
B) primarily producing proteins in the cytosol
C) constructing an extensive cell wall or extracellular matrix

D) enlarging its vacuole

B

23) A cell with an extensive area of smooth endoplasmic reticulum is specialized to _____.

A) play a role in storage
B) synthesize large quantities of lipids
C) actively export protein molecules

D) import and export protein molecules

B

24) Which structure is NOT part of the endomembrane system?

A) nuclear envelope
B) chloroplast
C) Golgi apparatus

D) plasma membrane

B

27) Which structure is the site of the synthesis of proteins that may be exported from the cell?

A) rough ER
B) plasmodesmata
C) Golgi vesicles

D) free cytoplasmic ribosomes

A

29) The liver is involved in detoxification of many poisons and drugs. Which of the following structures is primarily involved in this process and, therefore, abundant in liver cells?
A) rough ER
B) smooth ER

C) Golgi apparatus
D) nuclear envelope

B

30) Which of the following produces and modifies polysaccharides that will be secreted?

A) lysosome
B) mitochondrion
C) Golgi apparatus

D) peroxisome

C

31) What is the most likely pathway taken by a newly synthesized protein that will be secreted by a cell?
A) ER → Golgi → nucleus
B) Golgi → ER → lysosome

C) ER → Golgi → vesicles that fuse with plasma membrane
D) ER → lysosomes → vesicles that fuse with plasma membrane

C

32) Asbestos is a material that was once used extensively in construction. One risk from working in a building that contains asbestos is the development of asbestosis caused by the inhalation of asbestos fibers. Cells will phagocytize asbestos, but are not able to degrade it. As a result, asbestos fibers accumulate in _____.

A) mitochondria
B) ribosomes
C) peroxisomes
D) lysosomes

D

33) Which of the following is NOT true? Both chloroplasts and mitochondria _____.

A) have their own DNA
B) have multiple membranes
C) are part of the endomembrane system

D) are capable of reproducing themselves

C

34) Which organelle is the primary site of ATP synthesis in eukaryotic cells?

A) lysosome
B) mitochondrion
C) Golgi apparatus

D) peroxisome

B

35) Thylakoids, DNA, and ribosomes are all components found in _____.

A) chloroplasts
B) mitochondria
C) lysosomes

D) nuclei

A

36) In a plant cell, DNA may be found _____.
A) only in the nucleus
B) only in the nucleus and chloroplasts
C) in the nucleus, mitochondria, and chloroplasts
D) in the nucleus, mitochondria, chloroplasts, and peroxisomes

C

37) In a liver cell detoxifying alcohol and some other poisons, the enzymes of the peroxisome remove hydrogen from these molecules and _____.
A) combine the hydrogen with water molecules to generate hydrogen peroxide
B) use the hydrogen to break down hydrogen peroxide

C) transfer the hydrogen to the mitochondria
D) transfer the hydrogen to oxygen molecules to generate hydrogen peroxide

D

38) The evolution of eukaryotic cells most likely involved _____.
A) endosymbiosis of an aerobic bacterium in a larger host cell—the endosymbiont evolved into mitochondria
B) anaerobic archaea taking up residence inside a larger bacterial host cell to escape toxic oxygen—the anaerobic bacterium evolved into chloroplasts
C) an endosymbiotic fungal cell evolving into the nucleus
D) acquisition of an endomembrane system and subsequent evolution of mitochondria from a portion of the Golgi

A

39) Where are proteins produced other than on ribosomes free in the cytosol or ribosomes attached to the ER?
A) in the extracellular matrix
B) in the Golgi apparatus

C) in mitochondria
D) in the nucleolus

C

40) Suppose a cell has the following molecules and structures: enzymes, DNA, ribosomes, plasma membrane, and mitochondria. It could be a cell from _____.
A) a bacterium
B) an animal but not a plant

C) nearly any eukaryotic organism
D) a plant but not an animal

C

41) Cyanide binds with at least one molecule involved in producing ATP. If a cell is exposed to cyanide, most of the cyanide will be found within the _____.
A) mitochondria
B) peroxisomes

C) lysosomes
D) endoplasmic reticulum

A

42) Suppose a young boy is always tired and fatigued, suffering from a metabolic disease. Which of the following organelles is most likely involved in this disease?
A) lysosomes
B) Golgi apparatus

C) ribosomes
D) mitochondria

D

43) Motor proteins provide for molecular motion in cells by interacting with what types of cellular structures?
A) membrane proteins of the inner nuclear envelope
B) free ribosomes and ribosomes attached to the ER

C) components of the cytoskeleton
D) cellulose fibers in the cell wall

C

45) Vinblastine, a drug that inhibits microtubule polymerization, is used to treat some forms of cancer. Cancer cells given vinblastine would be unable to _____.
A) form cleavage furrows during cell division
B) migrate by amoeboid movement

C) separate chromosomes during cell division

D) maintain the shape of the nucleus

C

46) Amoebae move by crawling over a surface (cell crawling), which involves _____.
A) growth of actin filaments to form bulges in the plasma membrane
B) setting up microtubule extensions that vesicles can follow in the movement of cytoplasm

C) reinforcing the pseudopod with intermediate filaments
D) cytoplasmic streaming

A

49) Spherocytosis is a human blood disorder associated with a defective cytoskeletal protein in the red blood cells (RBCs). What do you suspect is the consequence of such a defect?
A) abnormally shaped RBCs
B) an insufficient supply of ATP in the RBCs

C) an insufficient supply of oxygen-transporting proteins in the RBCs

D) adherence of RBCs to blood vessel walls, causing plaque formation

A

50) Cytochalasin D is a drug that prevents actin polymerization. A cell treated with cytochalasin D will still be able to _____.
A) divide in two
B) contract muscle fibers

C) extend pseudopodia
D) move vesicles within a cell

D

51) Cells require which of the following to form cilia or flagella?

A) tubulin
B) laminin
C) actin

D) intermediate filaments

A

52) Which of the following statements about the cytoskeleton is true?
A) The cytoskeleton of eukaryotes is a static structure most resembling scaffolding used at construction sites.
B) Although microtubules are common within a cell, actin filaments are rarely found outside of the nucleus.
C) Movement of cilia and flagella is the result of motor proteins causing microtubules to move relative to each other.
D) Chemicals that block the assembly of the cytoskeleton would have little effect on a cell's response to external stimuli.

C

53) The cell walls of bacteria, fungi, and plant cells and the extracellular matrix of animal cells are all external to the plasma membrane. Which of the following is a characteristic common to all of these extracellular structures?
A) They must block water and small molecules to regulate the exchange of matter and energy with their environment.

B) They must provide a rigid structure that maintains an appropriate ratio of cell surface area to volume.
C) They are constructed of polymers that are synthesized in the cytoplasm and then transported out of the cell.

D) They are composed of a mixture of lipids and nucleotides.

C

54) A mutation that disrupts the ability of an animal cell to add polysaccharide modifications to proteins would most likely cause defects in its _____.
A) nuclear matrix and extracellular matrix
B) mitochondria and Golgi apparatus

C) Golgi apparatus and extracellular matrix

D) nuclear pores and secretory vesicles

C

56) Plasmodesmata in plant cells are most similar in function to which of the following structures in animal cells?
A) desmosomes
B) gap junctions

C) extracellular matrix
D) tight junctions

B

57) Ions can travel directly from the cytoplasm of one animal cell to the cytoplasm of an adjacent cell through _____.
A) plasmodesmata
B) tight junctions

C) desmosomes
D) gap junctions

D

58) In plant cells, the middle lamella _____.
A) allows adjacent cells to adhere to one another
B) prevents dehydration of adjacent cells
C) maintains the plant's circulatory system
D) allows for gas and nutrient exchange among adjacent cells

A

59) Where would you expect to find tight junctions?
A) in the epithelium of an animal's stomach
B) between the smooth endoplasmic reticulum and the rough endoplasmic reticulum

C) between plant cells in a woody plant
D) in the plasma membrane of prokaryotes

A

61) Gaucher disease is the most common of lipid storage diseases in humans. It is caused by a deficiency of an enzyme necessary for lipid metabolism. This leads to a collection of fatty material in organs of the body including the spleen, liver, kidneys, lungs, brain, and bone marrow.

Using your knowledge of the structure of eukaryotic cells, identify the statement below that best explains how internal membranes and the organelles of cells would be involved in Gaucher disease.
A) The mitochondria are most likely defective and do not produce adequate amounts of ATP needed for cellular respiration.

B) The rough endoplasmic reticulum contains too many ribosomes which results in an overproduction of the enzyme involved in carbohydrate catalysis.
C) The lysosomes lack sufficient amounts of enzymes necessary for the metabolism of lipids.

D) The Golgi apparatus produces vesicles with faulty membranes that leak their contents into the cytoplasm of the cell.

C

1) For a protein to be an integral membrane protein, it would have to be _____.

A) hydrophilic
B) hydrophobic
C) amphipathic, with at least one hydrophobic region

D) exposed on only one surface of the membrane

C

2) You have a planar bilayer with equal amounts of saturated and unsaturated phospholipids. After testing the permeability of this membrane to glucose, you increase the proportion of unsaturated phospholipids in the bilayer. What will happen to the membrane's permeability to glucose?

A) Permeability to glucose will increase.
B) Permeability to glucose will decrease.
C) Permeability to glucose will stay the same.
D) You cannot predict the outcome. You simply have to make the measurement.

A

3) According to the fluid mosaic model of cell membranes, phospholipids _____.
A) can move laterally along the plane of the membrane
B) frequently flip-flop from one side of the membrane to the other
C) occur in an uninterrupted bilayer, with membrane proteins restricted to the surface of the membrane

D) have hydrophilic tails in the interior of the membrane

A

4) The membranes of winter wheat are able to remain fluid when it is extremely cold by _____. A) increasing the percentage of unsaturated phospholipids in the membrane
B) increasing the percentage of cholesterol molecules in the membrane
C) decreasing the number of hydrophobic proteins in the membrane

D) cotransport of glucose and hydrogen

A

5) Some regions of the plasma membrane, called lipid rafts, have a higher concentration of cholesterol molecules. At higher temperatures, these regions _____.
A) are more fluid than the surrounding membrane
B) are less fluid than the surrounding membrane

C) detach from the plasma membrane and clog arteries
D) have higher rates of lateral diffusion of lipids and proteins into and out of these regions

B

6) Singer and Nicolson's fluid mosaic model of the membrane proposed that membranes_____. A) are a phospholipid bilayer between two layers of hydrophilic proteins
B) are a single layer of phospholipids and proteins
C) consist of protein molecules embedded in a fluid bilayer of phospholipids

D) consist of a mosaic of polysaccharides and proteins

C

8) Which of these are NOT embedded in the hydrophobic portion of the lipid bilayer at all? A) transmembrane proteins
B) integral proteins
C) peripheral proteins

D) All of these are embedded in the hydrophobic portion of the lipid bilayer.

C

9) Why are lipids and proteins free to move laterally in membranes?
A) The interior of the membrane is filled with liquid water.
B) Lipids and proteins repulse each other in the membrane.
C) Hydrophilic portions of the lipids are in the interior of the membrane.
D) There are only weak hydrophobic interactions in the interior of the membrane.

D

15) Cell membranes are asymmetrical. Which of the following statements is the most likely explanation for the membrane's asymmetrical nature?
A) Since the cell membrane forms a border between one cell and another in tightly packed tissues such as epithelium, the membrane must be asymmetrical

B) Since cell membranes communicate signals from one organism to another, the cell membranes must be asymmetrical.
C) The two sides of a cell membrane face different environments and carry out different functions.

D) Proteins only function on the cytoplasmic side of the cell membrane, which results in the membrane's asymmetrical nature.

C

16) In what way do the membranes of a eukaryotic cell vary?
A) Phospholipids are found only in certain membranes.
B) Certain proteins are unique to each membrane.
C) Only certain membranes of the cell are selectively permeable.
D) Some membranes have hydrophobic surfaces exposed to the cytoplasm, while others have hydrophilic surfaces facing the cytoplasm.

B

17) Which of the following is a reasonable explanation for why unsaturated fatty acids help keep a membrane more fluid at lower temperatures?
A) The double bonds form kinks in the fatty acid tails, preventing adjacent lipids from packing tightly.

B) Unsaturated fatty acids have a higher cholesterol content and, therefore, more cholesterol in membranes.
C) Unsaturated fatty acids are more polar than saturated fatty acids.
D) The double bonds block interaction among the hydrophilic head groups of the lipids

A

18) What kinds of molecules pass through a cell membrane most easily?

A) large and hydrophobic
B) small and hydrophobic
C) large polar

D) ionic

B

19) Which of the following most accurately describes selective permeability?
A) An input of energy is required for transport.
B) Lipid-soluble molecules pass through a membrane.
C) There must be a concentration gradient for molecules to pass through a membrane.

D) Only certain molecules can cross a cell membrane.

D

20) Which of the following is a characteristic feature of a carrier protein in a plasma membrane?

A) It exhibits a specificity for a particular type of molecule.
B) It requires the expenditure of cellular energy to function.
C) It works against diffusion.

D) It has no hydrophobic regions.

A

21) Which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly?
A) CO2

B) an amino acid

C) glucose

D) K+

A

22) Which of the following allows water to move much faster across cell membranes?

A) the sodium-potassium pump
B) ATP
C) peripheral proteins

D) aquaporins

D

24) Diffusion _____.
A) is very rapid over long distances
B) requires an expenditure of energy by the cell
C) is a passive process in which molecules move from a region of higher concentration to a region of lower concentration
D) requires integral proteins in the cell membrane

C

25) Which of the following processes includes all others?

A) osmosis
B) facilitated diffusion
C) passive transport

D) transport of an ion down its electrochemical gradient

C

26) When a cell is in equilibrium with its environment, which of the following occurs for substances that can diffuse through the cell?
A) There is random movement of substances into and out of the cell.
B) There is directed movement of substances into and out of the cell.

C) There is no movement of substances into and out of the cell.

D) All movement of molecules is directed by active transport.

A

27) Which of the following is true of osmosis?
A) Osmosis only takes place in red blood cells.
B) Osmosis is an energy-demanding or "active" process.
C) In osmosis, water moves across a membrane from areas of lower solute concentration to areas of higher solute concentration.
D) In osmosis, solutes move across a membrane from areas of lower water concentration to areas of higher water concentration.

C

The solutions in the two arms of this U-tube are separated by a membrane that is permeable to water and glucose but not to sucrose. Side A is half-filled with a solution of 2 M sucrose and 1 M glucose. Side B is half-filled with 1 M sucrose and 2 M glucose. Initially, the liquid levels on both sides are equal.

28) Refer t o the figure. Initially, in terms of tonicity, the solution in side A with respect to the solution in side B is _____.

A) hypotonic
B) isotonic

C) saturated
D) hypertonic

B

The solutions in the two arms of this U-tube are separated by a membrane that is permeable to water and glucose but not to sucrose. Side A is half-filled with a solution of 2 M sucrose and 1 M glucose. Side B is half-filled with 1 M sucrose and 2 M glucose. Initially, the liquid levels on both sides are equal.

29) Refer to the figure. After the system reaches equilibrium, what changes are observed?

A) The molarity of sucrose is higher than that of glucose on side A.
B) The water level is higher in side A than in side B.
C) The water level is unchanged.

D) The water level is higher in side B than in side A.

B

30) A patient was involved a serious accident and lost a large quantity of blood. In an attempt to replenish body fluids, distilled water—equal to the volume of blood lost—is added to the blood directly via one of his veins. What will be the most probable result of this transfusion?
A) The patient's red blood cells will shrivel up because the blood has become hypotonic compared to the cells.

B) The patient's red blood cells will swell and possibly burst because the blood has become hypotonic compared to the cells.
C) The patient's red blood cells will shrivel up because the blood has become hypertonic compared to the cells.

D) The patient's red blood cells will burst because the blood has become hypertonic compared to the cells.

B

The solutions in the arms of a U-tube are separated at the bottom of the tube by a selectively permeable membrane. The membrane is permeable to sodium chloride but not to glucose. Side A is filled with a solution of 0.4 M glucose and 0.5 M sodium chloride (NaCl), and side B is filled with a solution containing 0.8 M glucose and 0.4 M sodium chloride. Initially, the volume in both arms is the same..

31) Refer to the figure. At the beginning of the experiment,

A) side A is hypertonic to side B.
B) side A is hypotonic to side B.
C) side A is hypertonic to side B with respect to glucose.

D) side A is hypotonic to side B with respect to NaCl.

B

32) Refer to the figure. If you examine side A after three days, you should find _____.
A) a decrease in the concentration of NaCl and glucose and an increase in the water level

B) a decrease in the concentration of NaCl, an increase in water level, and no change in the concentration of glucose
C) a decrease in the concentration of NaCl and a decrease in the water level
D) no change in the concentration of NaCl and glucose and an increase in the water level

C

36) Celery stalks that are immersed in fresh water for several hours become stiff. Similar stalks left in a 0.15 M salt solution become limp. From this we can deduce that the fresh water_____.

A) and the salt solution are both hypertonic to the cells of the celery stalks
B) is hypotonic and the salt solution is hypertonic to the cells of the celery stalks

C) is hypertonic and the salt solution is hypotonic to the cells of the celery stalks

D) is isotonic and the salt solution is hypertonic to the cells of the celery stalks

B

37) What will happen to a red blood cell (RBC), which has an internal ion concentration of about 0.9 percent, if it is placed into a beaker of pure water?
A) The cell would shrink because the water in the beaker is hypotonic relative to the cytoplasm of the RBC.

B) The cell would shrink because the water in the beaker is hypertonic relative to the cytoplasm of the RBC.
C) The cell would swell because the water in the beaker is hypotonic relative to the cytoplasm of the RBC.

D) The cell will remain the same size because the solution outside the cell is isotonic.

C

38) Which of the following statements correctly describes the normal tonicity conditions for typical plant and animal cells? The animal cell is in _____.
A) a hypotonic solution, and the plant cell is in an isotonic solution
B) an isotonic solution, and the plant cell is in a hypertonic solution

C) a hypertonic solution, and the plant cell is in an isotonic solution

D) an isotonic solution, and the plant cell is in a hypotonic solution

D

39) In which of the following would there be the greatest need for osmoregulation?

A) an animal connective tissue cell bathed in isotonic body fluid
B) a salmon moving from a river into an ocean
C) a red blood cell surrounded by plasma

D) a plant being grown hydroponically in a watery mixture of designated nutrients

B

41) A sodium-potassium pump _____.
A) moves three potassium ions out of a cell and two sodium ions into a cell while producing an ATP for each cycle
B) move three sodium ions out of a cell and two potassium ions into a cell while consuming an ATP for each cycle
C) moves three potassium ions out of a cell and two sodium ions into a cell while consuming 2 ATP in each cycle
D) move three sodium ions out of a cell and two potassium ions into a cell and generates an ATP in each cycle

B

43) Which of the following membrane activities requires energy from ATP?
A) facilitated diffusion of chloride ions across the membrane through a chloride channel

B) movement of Na+ ions from a lower concentration in a mammalian cell to a higher concentration in the extracellular fluid
C) movement of glucose molecules into a bacterial cell from a medium containing a higher concentration of glucose than inside the cell
D) movement of carbon dioxide out of a paramecium

B

44) The voltage across a membrane is called the _____.

A) chemical gradient
B) membrane potential
C) osmotic potential

D) electrochemical gradient

B

45) Ions diffuse across membranes through specific ion channels down _____.

A) their chemical gradients
B) their concentration gradients
C) the electrical gradients

D) their electrochemical gradients

D

1) Which of the following is true of metabolism in its entirety in all organisms? A) Metabolism depends on a constant supply of energy from food.
B) Metabolism uses all of an organism's resources.
C) Metabolism consists of all the energy transformation reactions in an organism.

D) Metabolism manages the increase of entropy in an organism.

C

2) Which of the following is an example of potential rather than kinetic energy?

A) water rushing over Niagara Falls
B) light flashes emitted by a firefly
C) a molecule of glucose

D) a crawling beetle foraging for food

C

3) Most cells cannot harness heat to perform work because _____.

A) heat is not a form of energy
B) temperature is usually uniform throughout a cell
C) heat can never be used to do work

D) heat must remain constant during work

B

4) Which of the following involves a decrease in entropy?

A) condensation reactions
B) reactions that separate monomers
C) depolymerization reactions

D) hydrolysis reactions

A

5) Which term most precisely describes the cellular process of breaking down large molecules into smaller ones?
A) catabolism (catabolic pathways)
B) metabolism

C) anabolism (anabolic pathways)
D) dehydration

A

6) Anabolic pathways _____.
A) are usually highly spontaneous chemical reactions
B) consume energy to build up polymers from monomers
C) release energy as they degrade polymers to monomers
D) consume energy to decrease the entropy of the organism and its environment

B

8) For living organisms, which of the following is an important consequence of the first law of thermodynamics?
A) The energy content of an organism is constant.
B) The organism ultimately must obtain all of the necessary energy for life from its environment.

C) The entropy of an organism decreases with time as the organism grows in complexity.

D) Organisms grow by converting energy into organic matter.

B

9) Living organisms increase in complexity as they grow, resulting in a decrease in the entropy of an organism. How does this relate to the second law of thermodynamics?
A) Living organisms do not obey the second law of thermodynamics, which states that entropy must increase with time.

B) Life obeys the second law of thermodynamics because the decrease in entropy as the organism grows is exactly balanced by an increase in the entropy of the universe.
C) As a consequence of growing, organisms cause a greater increase in entropy in their environment than the decrease in entropy associated with their growth.

D) Living organisms are able to transform energy into entropy.

C

10) Which of the following statements is a logical consequence of the second law of thermodynamics?
A) If the entropy of a system increases, there must be a corresponding decrease in the entropy of the universe.
B) If there is an increase in the energy of a system, there must be a corresponding decrease in the energy of the rest of the universe.
C) Every chemical reaction must increase the total entropy of the universe.
D) Energy can be transferred or transformed, but it cannot be created or destroyed.

C

12) Which of the following types of reactions would decrease the entropy within a cell?

A) anabolic reactions
B) hydrolysis
C) digestion

D) catabolic reactions

A

15) A system at chemical equilibrium _____. A) consumes energy at a steady rate
B) releases energy at a steady rate
C) has zero kinetic energy

D) can do no work

D

16) Which of the following is true for all exergonic reactions?
A) The products have more total energy than the reactants.
B) The reaction proceeds with a net release of free energy.
C) The reaction goes only in a forward direction: all reactants will be converted to products, but no products will be converted to reactants.

D) A net input of energy from the surroundings is required for the reactions to proceed.

B

19) Choose the pair of terms that correctly completes this sentence: Catabolism is to anabolism as _____ is to _____.
A) exergonic; spontaneous
B) exergonic; endergonic

C) free energy; entropy
D) work; energy

B

21) Why is ATP an important molecule in metabolism?
A) Its hydrolysis provides an input of free energy for exergonic reactions.
B) It provides energy coupling between exergonic and endergonic reactions.
C) Its terminal phosphate group contains a strong covalent bond that, when hydrolyzed, releases free energy.
D) Its terminal phosphate bond has higher energy than the other two phosphate bonds.

B

24) Catabolic pathways _____.
A) combine molecules into more energy-rich molecules
B) supply energy, primarily in the form of ATP, for the cell's work

C) are endergonic
D) are spontaneous and do not need enzyme catalysis

B

25) When chemical, transport, or mechanical work is done by an organism, what happens to the heat generated?
A) It is used to power yet more cellular work.
B) It is used to store energy as more ATP.

C) It is used to generate ADP from nucleotide precursors.

D) It is lost to the environment.

D

30) Which of the following is true of enzymes?
A) Enzyme function is increased if the 3- D structure or conformation of an enzyme is altered.

B) Enzyme function is independent of physical and chemical environmental factors such as pH and temperature.
C) Enzymes increase the rate of chemical reaction by lowering activation energy barriers.
D) Enzymes increase the rate of chemical reaction by providing activation energy to the substrate.

C

32) The lock-and-key analogy for enzymes applies to the specificity of enzymes _____. A) as they form their tertiary and quaternary structure
B) binding to their substrate
C) interacting with water

D) interacting with ions

B

33) You have discovered an enzyme that can catalyze two different chemical reactions. Which of the following is most likely to be correct?
A) The enzyme contains α-helices and β-pleated sheets.
B) The enzyme is subject to competitive inhibition and allosteric regulation.

C) Two types of allosteric regulation occur: The binding of one molecule activates the enzyme, while the binding of a different molecule inhibits it.
D) Either the enzyme has two distinct active sites or the reactants involved in the two reactions are very similar in size and shape.

D

34) Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reaction's _____.
A) entropy
B) activation energy

C) equilibrium point
D) free-energy content

B

36) The active site of an enzyme is the region that _____.

A) binds allosteric regulators of the enzyme
B) is involved in the catalytic reaction of the enzyme
C) binds noncompetitive inhibitors of the enzyme

D) is inhibited by the presence of a coenzyme or a cofactor

B

37) According to the induced fit hypothesis of enzyme catalysis, _____.
A) the binding of the substrate depends on the shape of the active site
B) some enzymes change their structure when activators bind to the enzyme

C) the binding of the substrate changes the shape of the enzyme's active site

D) the active site creates a microenvironment ideal for the reaction

C

38) Increasing the substrate concentration in an enzymatic reaction could overcome which of the following?
A) the need for a coenzyme
B) allosteric inhibition

C) competitive inhibition
D) insufficient cofactors

C

40) A noncompetitive inhibitor decreases the rate of an enzyme reaction by _____.

A) binding at the active site of the enzyme
B) changing the shape of the enzyme's active site
C) changing the free energy change of the reaction

D) acting as a coenzyme for the reaction

B

Succinate dehydrogenase catalyzes the conversion of succinate to fumarate. The reaction is inhibited by malonic acid, which resembles succinate but cannot be acted upon by succinate dehydrogenase. Increasing the ratio of succinate to malonic acid reduces the inhibitory effect of malonic acid.

51) What is malonic acid's role with respect to succinate dehydrogenase? Malonic acid _____.

A) is a competitive inhibitor
B) blocks the binding of fumarate
C) is a noncompetitive inhibitor

D) is an allosteric regulator

A

56) You have isolated a previously unstudied protein, identified its complete structure in detail, and determined that it catalyzes the breakdown of a large substrate. You notice it has two binding sites. One of these is large, apparently the bonding site for the large substrate; the other is small, possibly a binding site for a regulatory molecule. What do these findings tell you about the mechanism of this protein?

A) It is probably a structural protein that is involved in cell-to-cell adhesion.

B) It is probably an enzyme that works through allosteric regulation.
C) It is probably an enzyme that works through competitive inhibition.
D) It is probably a cell membrane transport protein–like an ion channel.

B

57) Allosteric enzyme regulation is usually associated with _____.

A) feedback inhibition
B) activating activity
C) an enzyme with more than one subunit

D) the need for cofactors

C