Download Biology 1406 Quiz 2 Multiple-Choice Questions 1) When biologists

Biology 1406 Quiz 2
Multiple-Choice Questions
1) When biologists wish to study the internal ultrastructure of cells, they can achieve the finest
resolution by using
A) a phase-contrast light microscope.
B) a scanning electron microscope.
C) a transmission electronic microscope.
D) a confocal fluorescence microscope.
E) a super-resolution fluorescence microscope.
2) A primary objective of cell fractionation is to
A) view the structure of cell membranes.
B) sort cells based on their size and weight.
C) determine the size of various organelles.
D) separate the major organelles so that their particular functions can be determined.
E) separate lipid-soluble from water-soluble molecules.
3) All of the following are part of a prokaryotic cell except
A) DNA.
B) a cell wall.
C) a plasma membrane.
D) ribosomes.
E) an endoplasmic reticulum.
4) A mycoplasma is an organism with a diameter between 0.1 and 1.0 µm. What does the
organism's size tell you about how it might be classified?
A) It must be a single-celled protist.
B) It must be a single-celled fungus.
C) It could be almost any typical bacterium.
D) It could be a typical virus.
E) It could be a very small bacterium.
5) Which of the following statements concerning bacteria and archaea cells is correct?
A) Archaea cells contain small membrane-enclosed organelles; bacteria do not.
B) Archaea cells contain a membrane-bound nucleus; bacteria do not.
C) DNA is present in both archaea cells and bacteria cells.
D) DNA is present in the mitochondria of both bacteria and archaea cells.
E) DNA is only present in the mitochondria of archaea cells.
6) Which organelle or structure is absent in plant cells?
A) mitochondria
B) Golgi vesicles
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C) microtubules
D) centrosomes
E) peroxisomes
7) Which structure is the site of the synthesis of proteins that may be exported from the cell?
A) rough ER
B) lysosomes
C) plasmodesmata
D) Golgi vesicles
E) free cytoplasmic ribosomes
8) Hydrolytic enzymes must be segregated and packaged to prevent general destruction of
cellular components. Which of the following organelles contains these hydrolytic enzymes in
animal cells?
A) chloroplast
B) lysosome
C) central vacuole
D) peroxisome
E) glyoxysome
9) Which of the following produces and modifies polysaccharides that will be secreted?
A) lysosome
B) vacuole
C) mitochondrion
D) Golgi apparatus
E) peroxisome
10) Thylakoids, DNA, and ribosomes are all components found in
A) vacuoles.
B) chloroplasts.
C) mitochondria.
D) lysosomes.
E) nuclei.
11) 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) any multicellular organism, like a plant or an animal.
E) any kind of organism.
12) Which of the following contain the 9 + 2 arrangement of microtubules, consisting of nine
doublets of microtubules surrounding a pair of single microtubules?
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A) both motile cilia and primary (nonmotile) cilia
B) centrioles only
C) both flagella and motile cilia
D) both basal bodies and primary (nonmotile) cilia
E) both centrioles and basal bodies
13) Which of the following statements about the cytoskeleton is true?
A) The dynamic aspect of cytoskeletal function is made possible by the assembly and
disassembly of a large variety of proteins into complex aggregates.
B) Microfilaments are structurally rigid and resist compression, whereas microtubules resist
tension (stretching).
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 cause little effect on the cell's
response to external signals and stimuli.
E) Transport vesicles among the membranes of the endomembrane system produce the
cytoskeleton.
14) Singer and Nicolson's fluid mosaic model of the membrane proposed that
A) membranes are a phospholipid bilayer.
B) membranes are a phospholipid bilayer between two layers of hydrophilic proteins.
C) membranes are a single layer of phospholipids and proteins.
D) membranes consist of protein molecules embedded in a fluid bilayer of phospholipids.
E) membranes consist of a mosaic of polysaccharides and proteins.
15) According to the fluid mosaic model of cell membranes, which of the following is a true
statement about membrane phospholipids?
A) They can move laterally along the plane of the membrane.
B) They frequently flip-flop from one side of the membrane to the other.
C) They occur in an uninterrupted bilayer, with membrane proteins restricted to the surface of
the membrane.
D) They are free to depart from the membrane and dissolve in the surrounding solution.
E) They have hydrophilic tails in the interior of the membrane.
16) In order 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) completely covered with phospholipids.
E) exposed on only one surface of the membrane.
17) The primary function of polysaccharides attached to the glycoproteins and glycolipids of
animal cell membranes is
A) to facilitate diffusion of molecules down their concentration gradients.
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B) to actively transport molecules against their concentration gradients.
C) to maintain the integrity of a fluid mosaic membrane.
D) to maintain membrane fluidity at low temperatures.
E) to mediate cell-to-cell recognition.
18) 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) integrins
E) glycoproteins
19) Which of the following is a characteristic feature of a carrier protein in a plasma
membrane?
A) It is a peripheral membrane protein.
B) It exhibits a specificity for a particular type of molecule.
C) It requires the expenditure of cellular energy to function.
D) It works against diffusion.
E) It has few, if any, hydrophobic amino acids.
20) Which of the following membrane activities require energy from ATP hydrolysis?
A) facilitated diffusion of chloride ions across the membrane through a chloride channel
B) movement of water into a cell
C) Na+ ions moving out of a mammalian cell bathed in physiological saline
D) movement of glucose molecules into a bacterial cell from a medium containing a higher
concentration of glucose than inside the cell
E) movement of carbon dioxide out of a paramecium
21) White blood cells engulf bacteria through what process?
A) exocytosis
B) phagocytosis
C) pinocytosis
D) osmosis
E) receptor-mediated exocytosis
22) The difference between pinocytosis and receptor-mediated endocytosis is that
A) pinocytosis brings only water molecules into the cell, but receptor-mediated endocytosis
brings in other molecules as well.
B) pinocytosis increases the surface area of the plasma membrane whereas receptor-mediated
endocytosis decreases the plasma membrane surface area.
C) pinocytosis is nonselective in the molecules it brings into the cell, whereas receptormediated endocytosis offers more selectivity.
D) pinocytosis requires cellular energy, but receptor-mediated endocytosis does not.
E) pinocytosis can concentrate substances from the extracellular fluid, but receptor-mediated
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endocytosis cannot.
23) A bacterium engulfed by a white blood cell through phagocytosis will be digested by
enzymes contained in
A) peroxisomes.
B) lysosomes.
C) Golgi vesicles.
D) vacuoles.
E) secretory vesicles.
24) Cystic fibrosis is a genetic disease in humans in which the CFTR protein, which functions as a
chloride ion channel, is missing or nonfunctional in cell membranes. The CFTR protein belongs
to what category of membrane proteins?
A) gap junctions
B) aquaporins
C) electrogenic ion pumps
D) cotransporters
E) hydrophilic channels
25) Which term most precisely describes the cellular process of breaking down large molecules
into smaller ones?
A) catalysis
B) metabolism
C) anabolism
D) dehydration
E) catabolism
26) Which of the following is a statement of the first law of thermodynamics?
A) Energy cannot be created or destroyed.
B) The entropy of the universe is decreasing.
C) The entropy of the universe is constant.
D) Kinetic energy is stored energy that results from the specific arrangement of matter.
E) Energy cannot be transferred or transformed.
27) 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) Living organisms do not follow the laws of thermodynamics.
D) As a consequence of growing, organisms cause a greater increase in entropy in their
environment than the decrease in entropy associated with their growth.
E) Living organisms are able to transform energy into entropy.
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28) Which of the following types of reactions would decrease the entropy within a cell?
A) anabolic reactions
B) hydrolysis
C) respiration
D) digestion
E) catabolic reactions
29) Which of the following is an example of potential rather than kinetic energy?
A) the muscle contractions of a person mowing grass
B) water rushing over Niagara Falls
C) light flashes emitted by a firefly
D) a molecule of glucose
E) the flight of an insect foraging for food
30) A system at chemical equilibrium
A) consumes energy at a steady rate.
B) releases energy at a steady rate.
C) consumes or releases energy, depending on whether it is exergonic or endergonic.
D) has zero kinetic energy.
E) can do no work.
31) Which of the following best describes enthalpy (H)?
A) the total kinetic energy of a system
B) the heat content of a chemical system
C) the system's entropy
D) the cell's energy equilibrium
E) the condition of a cell that is not able to react
32) 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.
E) It is one of the four building blocks for DNA synthesis.
33) 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.
E) It is transported to specific organs such as the brain.
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34) Which of the following statements is true about enzyme-catalyzed reactions?
A) The reaction is faster than the same reaction in the absence of the enzyme.
B) The free energy change of the reaction is opposite from the reaction that occurs in the
absence of the enzyme.
C) The reaction always goes in the direction toward chemical equilibrium.
D) Enzyme-catalyzed reactions require energy to activate the enzyme.
E) Enzyme-catalyzed reactions release more free energy than noncatalyzed reactions.
35) According to the induced fit hypothesis of enzyme catalysis, which of the following is
correct?
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) A competitive inhibitor can outcompete the substrate for the active site.
D) The binding of the substrate changes the shape of the enzyme's active site.
E) The active site creates a microenvironment ideal for the reaction.
36) When you have a severe fever, what grave consequence may occur if the fever is not
controlled?
A) destruction of your enzymes' primary structure
B) removal of amine groups from your proteins
C) change in the tertiary structure of your enzymes
D) removal of the amino acids in active sites of your enzymes
E) binding of your enzymes to inappropriate substrates
37) The mechanism in which the end product of a metabolic pathway inhibits an earlier step in
the pathway is most precisely described as
A) metabolic inhibition.
B) feedback inhibition.
C) allosteric inhibition.
D) noncooperative inhibition.
E) reversible inhibition.
38) Allosteric enzyme regulation is usually associated with
A) lack of cooperativity.
B) feedback inhibition.
C) activating activity.
D) an enzyme with more than one subunit.
E) the need for cofactors.
39) What is the term for metabolic pathways that release stored energy by breaking down
complex molecules?
A) anabolic pathways
B) catabolic pathways
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C) fermentation pathways
D) thermodynamic pathways
E) bioenergetic pathways
40) When a molecule of NAD+ (nicotinamide adenine dinucleotide) gains a hydrogen atom (not
a proton), the molecule becomes
A) dehydrogenated.
B) oxidized.
C) reduced.
D) redoxed.
E) hydrolyzed.
41) Where does glycolysis take place in eukaryotic cells?
A) mitochondrial matrix
B) mitochondrial outer membrane
C) mitochondrial inner membrane
D) mitochondrial intermembrane space
E) cytosol
42) In addition to ATP, what are the end products of glycolysis?
A) CO2 and H2O
B) CO2 and pyruvate
C) NADH and pyruvate
D) CO2 and NADH
E) H2O, FADH2, and citrate
43) Starting with one molecule of glucose, the energy-containing products of glycolysis are
A) 2 NAD+, 2 pyruvate, and 2 ATP.
B) 2 NADH, 2 pyruvate, and 2 ATP.
C) 2 FADH2, 2 pyruvate, and 4 ATP.
D) 6 CO2, 2 ATP, and 2 pyruvate.
E) 6 CO2, 30 ATP, and 2 pyruvate.
44) Why is glycolysis described as having an investment phase and a payoff phase?
A) It both splits molecules and assembles molecules.
B) It attaches and detaches phosphate groups.
C) It uses glucose and generates pyruvate.
D) It shifts molecules from cytosol to mitochondrion.
E) It uses stored ATP and then forms a net increase in ATP.
45) In cellular respiration, the energy for most ATP synthesis is supplied by
A) high energy phosphate bonds in organic molecules.
B) a proton gradient across a membrane.
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C) converting oxygen to ATP.
D) transferring electrons from organic molecules to pyruvate.
E) generating carbon dioxide and oxygen in the electron transport chain.
46) During aerobic respiration, H2O is formed. Where does the oxygen atom for the formation
of the water come from?
A) carbon dioxide (CO2)
B) glucose (C6H12O6)
C) molecular oxygen (O2)
D) pyruvate (C3H3O3-)
E) lactate (C3H5O3-)
47) When hydrogen ions are pumped from the mitochondrial matrix across the inner
membrane and into the intermembrane space, the result is the
A) formation of ATP.
B) reduction of NAD+.
C) restoration of the Na+/K+ balance across the membrane.
D) creation of a proton-motive force.
E) lowering of pH in the mitochondrial matrix.
48) It is possible to prepare vesicles from portions of the inner mitochondrial membrane. Which
one of the following processes could still be carried on by this isolated inner membrane?
A) the citric acid cycle
B) oxidative phosphorylation
C) glycolysis and fermentation
D) reduction of NAD+
E) both the citric acid cycle and oxidative phosphorylation
49) Which of the following produces the most ATP when glucose (C6H12O6) is completely
oxidized to carbon dioxide (CO2) and water?
A) glycolysis
B) fermentation
C) oxidation of pyruvate to acetyl CoA
D) citric acid cycle
E) oxidative phosphorylation (chemiosmosis)
50) In a mitochondrion, if the matrix ATP concentration is high, and the intermembrane space
proton concentration is too low to generate sufficient proton-motive force, then
A) ATP synthase will increase the rate of ATP synthesis.
B) ATP synthase will stop working.
C) ATP synthase will hydrolyze ATP and pump protons into the intermembrane space.
D) ATP synthase will hydrolyze ATP and pump protons into the matrix.
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