Which of the following statements about cells is correct?
Both prokaryotic and eukaryotic organisms are made up of cells.
A cell lacking which of the following structures is most likely to be a prokaryote?
Nuclear membrane
Which of the following statements is true regarding the complexity of biological systems?
Knowing the function of a component of a living system can provide insights into the structure and organization of the living system.
Which of the following statements about genetic information is correct?
All forms of life employ the same genetic code
Which of the following is an example of genetic variation?
One sibling has brown eyes, the other has green
About 20-25% of the 92 natural elements are known to be essential to life. Which four of these elements make up approximately 96% of living matter?
carbon, hydrogen, nitrogen, oxygen
A controlled experiment is one in which
there are at least two groups, one of which does not receive the experimental treatment.
What is the difference between covalent bonds and ionic bonds?
Covalent bonds involve the sharing of electrons between atoms: ionic bonds involve the electrical attraction between atoms.
Under which of the following conditions will an atom be the most stable?
when all of the electron orbitals in the valence shell are filled
How is a covalent bond formed?
two atoms share one electron
Which of the following is a hydrophobic material?
table salt
The partial negative charge in a molecule of water occurs because
the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom nucleus than around the hydrogen atom nucleus
Which of the following properties of water is responsible for the formation of raindrops?
cohesion property
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.)
10°C
Which of the following functional groups is hydrophobic in nature?
methyl
ATP is necessary for life because
it is the principle energy carrying molecule in a cell
Choose the Figure that depicts polymer synthesis.
Figure 1 = Away from the molecules
Figure 2 = Toward the molecules
Figure 1
A polysaccharide is a polymer made up of which kind of monomers?
simple sugars
The tertiary structure of a polypeptide is the
overall three-dimensional shape of a fully folded polypeptide.
The tertiary structure of a polypeptide is the
overall three-dimensional shape of a fully folded polypeptide.
Which of the following statements about proteins is true?
Some proteins form a complete 3-D structure only when they interact with their targets.
Which of the following ratios of nucleotides is constant for DNA?
A + G= T + C
Which structure is not part of the endomembrane system?
chloroplast
Which structure is common to plant and animal cells?
mitochondrion
Which of the following statements best describes one major difference between prokaryotic cells and eukaryotic cells?
Eukaryotic cells have membrane-bound organelles, while prokaryotic cells do not.
Which of the following parameters is most likely to limit the maximum size of a cell?
the ratio of surface area to volume of cytoplasm
Tay-Sachs disease is a human genetic abnormality that results in cells accumulating very large, complex, undigested lipids. Which cellular organelle must be defective in this condition?
the lysosome
Disruption of nuclear pore complexes in a eukaryotic cell will most likely interfere with the transport of which of the following molecules out of the nucleus?
mRNA
Examination of a cell by transmission electron microscopy reveals a high density of ribosomes in the cytoplasm. This observation suggests that the cell is actively producing large amounts of which of the following molecules?
proteins
Which of the following organelles often occupy the majority of the volume of a plant cell?
central vacuole
Which of the following organelles is primarily responsible for the production and modification of polysaccharides that will be secreted?
Golgi apparatus
A newly synthesized protein destined for secretion from a eukaryotic cell will generally follow which of the pathways listed below?
rough ER -> Golgi -> transport vesicle - plasma membrane
An organelle in a newly discovered cell contains thylakoids, DNA, and ribosomes. These findings suggest that this organelle is most likely similar to which of the following organelles?
chloroplasts
A young child who suffers from a metabolic disease is always tired and fatigued.
Which of the following organelles is most likely malfunctioning in this disease?
mitochondria
Vinblastine, a drug that inhibits microtubule polymerization, is used to treat some forms of cancer. Cancer cells treated with vinblastine would most likely be unable to perform which of the following cellular functions?
separate chromosomes during cell division
A phospholipid bilayer with equal amounts of saturated and unsaturated fatty acids displays a specific permeability to glucose. What effect will increasing the proportion of unsaturated fatty acids in the bilayer have on the membrane's permeability to glucose?
Permeability to glucose will increase.
Cell membranes have distinct inside and outside faces. Which of the following statements is the most plausible explanation for the asymmetrical nature of the two layers of the membrane?
The two layers of a cell membrane face different environments and carry out different functions.
A new drug designed for the treatment of lung cancer must specifically enter the cytoplasm of lung cells while not entering the cells of other tissues. Which of the following characteristics would likely enhance the specificity of this drug?
the similarity of the drug molecule to other molecules normally transported lung cells
Which of the following statements best describes a characteristic feature of diffusion?
It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.
What will happen to a red blood cell (RBC), which has an internal ion content of about 0.9%, if it is placed into a beaker of pure water?
The cell will swell because the water in the beaker is hypotonic relative to the cytoplasm of the RBC.
An organism with a cell wall would most likely be unable to take in materials through which of the following processes?
phagocytosis
In what way do the membranes of a eukaryotic cell vary?
Certain proteins are unique to each membrane.
According to the fluid mosaic model of membrane structure, proteins of the membrane are mostly
embedded in a lipid bilayer.
Human immunodeficiency virus (HIV) infects cells that have both CD4 and CCRS cell surface molecules. The viral nucleic acid molecules are enclosed in a protein capsid, and the protein capsid is itself contained inside an envelope consisting of a lipid bilayer membrane and viral glycoproteins. One hypothesis for viral entry into cells is that binding of HIV membrane glycoproteins to CD4 and CCR5 initiates fusion of the HIV membrane with the plasma membrane, releasing the viral capsid into the cytoplasm. An alternative hypothesis is that HIV gains entry into the cell via receptor-mediated endocytosis, and membrane fusion occurs in the endocytotic vesicle. To test these alternative hypotheses for HIV entry, researchers labeled the lipids on the HIV membrane with a red fluorescent dye.
What would be observed by live-cell fluorescence microscopy immediately after HIV entry if HIV enters the cell by endocytosis first, and then later fuses with the endocytic vesicle membrane?
The red fluorescent dye-labeled lipids will appear in the infected cell's interior.
Which of the following processes includes all the others?
passive transport
Which of the following factors, according to an evolutionary worldview, most likely helped early plants colonize land?
formation of mutualistic associations with fungi
Which of the following statements correctly describes a characteristic of archegonia?
they may contain sporophyte embryos
Assuming that they all belong to the same plant, which of the following lists the structures from largest to smallest?
gametophytes, antheridia, gametes
Some fungal species live in plants and can kill herbivores that feed on the plant. What type of relationship does this fungus have with its host?
mutualistic
In an investigation of Sphagnum growth, researchers measured the growth of four different S. Juscum species (labeled a, ab, bc, and c in the figure) at four temperatures. The results of the investigation are represented in the graph.
fuscum species are best adapted to live in warm climates.
Researchers grew two plants of different species (plant 1 and plant 2) and added the same mycorrhizal species to the soil. They then measured the growth of each plant after one month. Plant 1 grew significantly more than plant 2. Which of the following conclusions is most consistent with these results?
plant 1 formed a mutualistic relationship with the mycorrhizal fungi and plant 2 did not
Some companies advertise and sell mycorrhizae to home gardeners and commercial farms, claiming that the presence of mycorrhizae improves plant growth and survival. If the company conducted experiments on plants with and without mycorrhizae, which of the following results would support their claim?
increased production of corn ears in plants with mycorrhizae than in plants without mycorrhizae
Name the organelle in a cell that secretes many MODIFIED proteins
Golgi Bodies
Name the organelle in a cell recycles old or damaged organelles
Lysosomes
Which is part of the endomembrane system?
All the above
Name the organelle in a cell that converts solar energy to chemical energy
Chloroplast
Which of the following conditions is required for a target organ to respond to a particular hormone?
The target organ must have receptors that recognize and bind the hormone molecule.
When a neuron responds to a particular neurotransmitter by opening gated ion channels, the neurotransmitter is serving as a part of the signal pathway?
signal molecule
Which of the following signal transduction proteins typically functions by forming dimers after binding to a signal molecule?
receptor tyrosine kinases
Which of the following signal transduction proteins are activated by phosphorylation after binding to a signal molecule?
receptor tyrosine kinases
Certain receptor tyrosine kinases (RTKs) that promote excessive cell division are found at high levels in various cancer cells. HER2 is an RTK that is present at excessively high levels in some breast cancer cells. Herceptin is a protein that binds to HER2 and inhibits cell division. Herceptin may be an effective treatment for breast cancer treatment under which of the following conditions?
If the patient's cancer cells have excessive levels of HER2.
Which of the following activities would be inhibited by a drug that specifically blocks the addition of phosphate groups to proteins?
phosphorylation cascade
A signal transmitted via phosphorylation of a series of proteins is generally associated with which of the following events?
conformational changes to each protein in the series
How does the toxin of Vibrio cholerae cause profuse diarrhea?
It modifies a G protein involved in regulating salt and water secretion.
Consider the following pathway:epinephrine -> G protein-coupled receptor -> G protein -› adenylyl cyclase - › CAMP
Which of the following molecules serves as the second messenger in this pathway?
CAMP
Which of the sequences below best describes the sequential steps (numbered 1-5) in a signal transduction pathway that utilizes a G protein-coupled receptor?
- The signal-receptor complex activates a G2 protein
- Protein kinases are activated.
- A signal molecule binds to a receptor.
- Target proteins are phosphorylated.
- cAMP is produced.
3,1,5,2,4
Which of the following statements describes a characteristic feature of metaphase?
alignment of chromosomes on equator of the cell
Which of the following statements best explains how neurons and some other specialized cells divide infrequently?
They have entered into G 0 .
Cell A has half as much DNA as cells B, C, and D in a mitotically active tissue. Cell A is most likely in
G1
Which of the following is a molecule that helps to "turn off" the expression of genes in a cell?
corepressor
When taken up by a cell, which of the following molecules binds to a repressor so that the repressor no longer binds to an operator?
inducer
The unlettered circle at the top of the accompanying diagram shows a diploid nucleus with four unreplicated chromosomes. The circles labeled 1 to 5 show various combinations of these chromosomes. Which chromosomal configurations would be observed at prometaphase of mitosis?
II
Which of the following conditions is most likely to result in transcription of the lac operon?
Which of the following conditions is most likely to result in transcription of the lac operon?
Most cells that have become transformed into cancer cells have which of the following characteristics when compared to normal, healthy cells?
Shorter cell cycle
Binding of a signaling molecule to which type of receptor leads directly to a change in the distribution of ions on opposite sides of the membrane?
ligand-gated ion channel