Mini exams for final exam

Use the figure to answer the question. enzyme A enzyme B A -----------> B ------------> C The figure shows a simple metabolic pathway. According to Beadle and Tatum's hypothesis, how many genes are necessary for this pathway?

2

Which of the following statements describes a central role that ATP plays in cellular metabolism? A) ATP provides energy coupling between exergonic and endergonic reactions. B) Its terminal phosphate bond is stronger than most covalent bonds in other biological macromolecules. C) Hydrolysis of ATP provides an input of free energy for exergonic reactions. D) Hydrolysis of the terminal phosphate group stores free energy that is used for cellular work.

A) ATP provides energy coupling between exergonic and endergonic reactions.

Which of the following statements about enzyme function is true? A) Enzymes increase the rate of chemical reactions by lowering activation energy barriers. B) Enzyme function is independent of physical and chemical environmental factors such as pH and temperature. C) Enzymes increase the rate of chemical reactions by providing activation energy to the substrate. D) Enzyme function is generally increased if the three-dimensional structure or conformation of an enzyme is altered

A) Enzymes increase the rate of chemical reactions by lowering activation energy barriers.

Which of the following statements 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 are more nonpolar than saturated fatty acids. C) The double bonds block interaction among the hydrophilic head groups of the lipids. D) Unsaturated fatty acids have a higher cholesterol content, which prevents adjacent lipids from packing tightly.

A) The double bonds form kinks in the fatty acid tails, preventing adjacent lipids from packing tightly.

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 phosphodiester bonds between deoxyribose sugars would be broken. B) The two strands of the double helix would separate. C) All bases would be separated from the deoxyribose sugars. D) The pyrimidines would be separated from the deoxyribose sugars. E) The purines would be separated from the deoxyribose sugars.

A) The phosphodiester bonds between deoxyribose sugars would be broken.

For a protein to be an integral membrane protein, it would have to be ________. A) amphipathic, with at least one hydrophobic region B) hydrophilic C) exposed on only one surface of the membrane D) hydrophobic

A) amphipathic, with at least one hydrophobic region

Which of the following terms most precisely describes the cellular process of breaking down large molecules into smaller ones? A) anabolism (anabolic pathways) B) dehydration C) catabolism (catabolic pathways) D) metabolism

A) anabolism (anabolic pathways)

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 disaccharide B) as a polysaccharide C) as a pentose D) as a monosaccharide E) as a hexose

A) as a disaccharide

A decrease in entropy is associated with which type of reaction? A) dehydration B) depolymerization C) hydrolysis D) catabolic

A) dehydration

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

A) different side chains (R groups) attached to an alpha carbon

A chemical reaction that has a positive ̇G is best described as ________. A) endergonic B) enthalpic C) exergonic D) spontaneous

A) endergonic

The relationship between catabolism and anabolism is most similar to the relationship between which of the following pairs of terms? A) exergonic; endergonic B) exergonic; spontaneous C) free energy; entropy D) work; free energy

A) exergonic; endergonic

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, or in a transmembrane portion interacting with lipid fatty acid chains B) anywhere in the protein, with equal probability C) on the exterior surface of the protein, interacting with water D) in the interior of the folded protein, away from water E) in the transmembrane portion interacting with lipid fatty acid chains

A) in the interior of the folded protein, away from water, or in a transmembrane portion interacting with lipid fatty acid chains

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

A) increasing the proportion of unsaturated phospholipids in the membrane

According to the fluid mosaic model, a membrane ________. A) is composed of a fluid bilayer of phospholipids with embedded amphipathic proteins B) is composed of a mosaic of fluid polysaccharides and amphipathic proteins C) is composed of a single layer of fluid phospholipids between two layers of hydrophilic proteins D) is composed of a fluid bilayer of phospholipids between two layers of hydrophilic proteins

A) is composed of a fluid bilayer of phospholipids with embedded amphipathic proteins

A sodium-potassium pump ________. A) moves three sodium ions out of a cell and two potassium ions into a cell using energy from ATP hydrolysis B) moves three potassium ions out of a cell and two sodium ions into a cell using energy from ATP hydrolysis C) move three sodium ions out of a cell and two potassium ions into a cell and generates an ATP in each cycle D) moves three potassium ions out of a cell and two sodium ions into a cell while producing ATP for each cycle

A) moves three sodium ions out of a cell and two potassium ions into a cell using energy from ATP hydrolysis

A cell has the following molecules and structures: enzymes, DNA, ribosomes, plasma membrane, and mitochondria. It could be a cell from A) nearly any eukaryotic organism. B) an animal, but not a plant. C) any multicellular organism, like a plant or an animal. D) a bacterium. E) any kind of organism.

A) nearly any eukaryotic organism.

What kinds of molecules pass through a cell membrane most easily? A) small and hydrophobic B) small and ionic C) large polar D) large and hydrophobic

A) small and hydrophobic

During a laboratory experiment, you discover that an enzyme-catalyzed reaction has a NJG of -20 kcal/mol. If you double the amount of enzyme in the reaction, what will be the NJG for the new reaction? A) +20 kcal/mol B) -20 kcal/mol C) -10 kcal/mol D) -40 kcal/mol

B) -20 kcal/mol

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. When the system illustrated above reaches equilibrium, the sugar concentrations on both sides of the U-tube will be ________. A) 1 M sucrose, 1 M glucose B) 1.5 M sucrose, 1.5 M glucose C) 2 M sucrose, 1 M glucose D) 1 M sucrose, 2 M glucose

B) 1.5 M sucrose, 1.5 M glucose

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

B) 5'TGCAAT3'.

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

B) DNA nucleotides contain a different sugar than RNA nucleotides.

Which of the following characteristics is most likely to be associated with an enzyme that catalyzes two different chemical reactions? A) The enzyme is composed of at least two subunits. B) Either the enzyme has two distinct active sites or the substrates involved in the two reactions have very similar structures. C) The enzyme contains ΅-helices and Ά-pleated sheets. D) The enzyme is subject to competitive inhibition and allosteric regulation.

B) Either the enzyme has two distinct active sites or the substrates involved in the two reactions have very similar structures.

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 pores and secretory vesicles. B) Golgi apparatus and extracellular matrix. C) mitochondria and Golgi apparatus. D) nuclear lamina and nuclear matrix. E) nuclear matrix and extracellular matrix.

B) Golgi apparatus and extracellular matrix.

Which of the following statements describes what happens to a molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction? A) It loses electrons and gains potential energy. B) It loses electrons and loses potential energy. C) It gains electrons and loses potential energy. D) It gains electrons and gains potential energy.

B) It loses electrons and loses potential energy.

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 and on the exterior 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 of the globular proteins

B) Leucine would be in the interior, and serine would be on the exterior of the globular protein.

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

B) Metabolism consists of all the energy transformation reactions in an organism.

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? A) Permeability will decrease initially then increase as the bilayer fills with glucose. B) Permeability to glucose will increase. C) Permeability to glucose will stay the same. D) Permeability to glucose will decrease.

B) Permeability to glucose will increase.

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) As a consequence of growth, the decrease in entropy of the organism is associated with a corresponding decrease in the entropy of the universe. B) The decrease in entropy is associated with growth of an organism. As a consequence of growth, organisms cause a greater increase in entropy in their environment than the decrease in entropy associated with their increased complexity. C) Living organisms are able to transform chemical energy into entropy. D) Living organisms do not obey the second law of thermodynamics, which states that the entropy of an organism increases with each energy transformation.

B) The decrease in entropy is associated with growth of an organism. As a consequence of growth, organisms cause a greater increase in entropy in their environment than the decrease in entropy associated with their increased complexity.

Which of the following statements about anabolic pathways is true? A) They decrease the entropy of the organism and its environment. B) They consume energy to build up polymers from monomers. C) They are usually spontaneous chemical reactions. D) They release energy by degrading polymers to monomers.

B) They consume energy to build up polymers from monomers.

What is the name of the thermodynamic barrier that must be overcome before products are formed in a spontaneous reaction? A) the equilibrium point B) activation energy C) entropy D) free energy

B) activation energy

All of the following are part of a prokaryotic cell except A) ribosomes. B) an endoplasmic reticulum. C) a cell wall. D) a plasma membrane. E) DNA.

B) an endoplasmic reticulum.

Which of the following types of reactions would decrease the entropy within a cell? A) digestion B) anabolic reactions C) hydrolysis D) catabolic reactions

B) anabolic reactions

How does a noncompetitive inhibitor decrease the rate of an enzyme-catalyzed reaction? A) by binding to the substrate, thus changing its shape so that it no longer binds to the active site of the enzyme B) by binding to an allosteric site, thus changing the shape of the active site of the enzyme C) by binding to the active site of the enzyme, thus preventing binding of the normal substrate D) by decreasing the free-energy change of the reaction catalyzed by the enzyme

B) by binding to an allosteric site, thus changing the shape of the active site of the enzyme

Which of the following types of molecules lack hydrophilic domains? A) integral membrane proteins B) cholesterol C) transmembrane proteins D) peripheral membrane proteins

B) cholesterol

Motor proteins provide for molecular motion in cells by interacting with what types of cellular structures? A) cellulose fibers in the cell wall B) cytoskeletal structures C) ribosomes D) membrane proteins E) sites of energy production in cellular respiration

B) cytoskeletal structures

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

B) in the nucleus, mitochondria, and chloroplasts

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

Which of the following types of molecules are hydrophilic and therefore excluded from the hydrophobic portion of the phospholipid bilayer? A) transmembrane proteins B) peripheral membrane proteins C) integral membrane proteins D) cholesterol

B) peripheral membrane proteins

The volume enclosed by the plasma membrane of plant cells is often much larger than the corresponding volume in animal cells. The most reasonable explanation for this observation is that A) plant cells can have lower surface-to-volume ratios than animal cells because plant cells synthesize their own nutrients. B) plant cells contain a large vacuole that reduces the volume of the cytoplasm. C) plant cells are capable of having a much higher surface-to-volume ratio than animal cells. D) animal cells are more spherical, whereas plant cells are elongated. E) plant cells have a much more highly convoluted (folded) plasma membrane than animal cells.

B) plant cells contain a large vacuole that reduces the volume of the cytoplasm

When a potassium ion (K+) moves from the soil into the vacuole of a cell on the surface of a root, it must pass through several cellular structures. Which of the following correctly describes the order in which these structures will be encountered by the ion? A) primary cell wall plasma membrane lysosome cytoplasm vacuole B) primary cell wall plasma membrane cytoplasm vacuole C) secondary cell wall plasma membrane primary cell wall cytoplasm vacuole D) plasma membrane primary cell wall cytoplasm vacuole E) primary cell wall plasma membrane cytoplasm secondary cell wall vacuole

B) primary cell wall plasma membrane cytoplasm vacuole

The phosphate transport system in bacteria imports phosphate into the cell even when the concentration of phosphate outside the cell is much lower than the cytoplasmic phosphate concentration. Phosphate import depends on a pH gradient across the membraneNmore acidic outside the cell than inside the cell. In this bacterial cell, phosphate transport is an example of ________. A) primary active transport B) secondary active transport (cotransport) C) passive diffusion D) facilitated diffusion

B) secondary active transport (cotransport)

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. In the U-tube illustrated above, ________. A) side A is more turgid than side B B) side A is isotonic to side B C) side A is hypotonic to side B D) side A is hypertonic to side B

B) side A is isotonic to side B

Which of the following are least likely to diffuse through the phospholipid bilayer of a cell membrane? A) large hydrophobic molecules B) small ions C) carbon dioxide D) small hydrophobic molecules

B) small ions

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) transfer the hydrogen to oxygen molecules to generate hydrogen peroxide. C) transfer the hydrogen to the mitochondria. D) use the hydrogen to break down hydrogen peroxide.

B) transfer the hydrogen to oxygen molecules to generate hydrogen peroxide.

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

B) triacylglycerides, polysaccharides, and proteins

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 consumed during homeostasis, but water is generated during periods of growth. B) water is consumed by animal metabolism. C) the water consumed is exactly balanced by the water generated, to maintain homeostasis. D) water is generated by animal metabolism. E) water is generated during homeostasis, but water is consumed during periods of growth.

B) water is consumed by animal metabolism.

Which of the following statements is an important consequence of the first law of thermodynamics for a living organism? A) Organisms grow by converting energy into organic matter. B) The entropy of an organism decreases with time as the organism grows in complexity. C) An organism ultimately must obtain all of the necessary energy for life from its environment. D) The energy content of an organism is constant.

C) An organism ultimately must obtain all of the necessary energy for life from its environment.

Which component in the accompanying figure is a microfilament (actin filament) of the cytoskeleton? A) A B) B C) C D) D

C) C

Five dialysis bags, constructed of a type of membrane that is permeable to water and impermeable to sucrose, were filled with various concentrations of sucrose and then placed in separate beakers containing an initial concentration of 0.6 M sucrose solution. At 10-minute intervals, the bags were massed (weighed), and the percent change in mass of each bag was graphed. Which line in the graph represents the bag that contained a solution isotonic to the 0.6 M solution at the beginning of the experiment? A) A increasing curve B) B increasing linear C) C flat D) D decreasing linear

C) C flat

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) C3H6O3 C) C18H32O16 D) C18H10O15 E) C6H10O5

C) C18H32O16

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

C) Certain proteins are unique to each membrane.

Centrioles, cilia, flagella, and basal bodies have remarkably similar structural elements and arrangements. Which of the following hypotheses is most plausible in light of such structural similarities? A) Cilia and flagella coevolved in the same ancestral eukaryotic organism. B) Motor proteins such as dynein must have evolved before any of these four kinds of structure. C) Cilia and flagella arise from the centrioles. D) Natural selection for cell motility repeatedly selected for microtubular arrays in circular patterns in the evolution of each of these structures. E) Loss of basal bodies should lead to loss of all cilia, flagella, and centrioles.

C) Cilia and flagella arise from the centrioles.

When ATP releases some energy, it also releases inorganic phosphate. What happens to the inorganic phosphate in the cell? A) It enters the nucleus to be incorporated in a nucleotide. B) It is secreted as waste. C) It may be used to form a phosphorylated intermediate. D) It is used only to regenerate more ATP.

C) It may be used to form a phosphorylated intermediate.

Which of the following would likely diffuse through the lipid bilayer of a plasma membrane most rapidly? A) Na+ B) an amino acid C) O2 D) sucrose

C) O2

What happens to a glucose molecule when it loses a hydrogen atom as the result of an oxidation-reduction reaction? A) The glucose molecule is hydrolyzed. B) The glucose molecule is reduced. C) The glucose molecule is oxidized. D) The glucose molecule is an oxidizing agent.

C) The glucose molecule is oxidized.

What happens when electrons are passed from one atom to a more electronegative atom? A) The more electronegative atom is oxidized, and energy is released. B) The more electronegative atom is reduced, and energy is consumed. C) The more electronegative atom is reduced, and energy is released. D) The more electronegative atom is oxidized, and energy is consumed.

C) The more electronegative atom is reduced, and energy is released.

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

C) The reaction proceeds with a net release of free energy.

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

C) They are both polymers of glucose.

What do the cell walls of plants and the extracellular matrix of animal cells have in common? A) Their proteins are made by free cytoplasmic ribosomes. B) They limit the passage of small molecules. C) They have functional connections with the cytoskeleton inside the cell. D) They are largely composed of phospholipids and glycoproteins. E) They form rigid structures that provide structural support for cells but limit their expansion.

C) They have functional connections with the cytoskeleton inside the cell.

The nuclear lamina is an array of filaments on the inner side of the nuclear membrane. If a method were found that could cause the lamina to fall into disarray, what would you expect to be the most likely consequence? A) the loss of all nuclear function B) failure of chromosomes to carry genetic information C) a change in the shape of the nucleus D) the inability of the nucleus to divide during cell division E) inability of the nucleus to keep out destructive chemicals

C) a change in the shape of the nucleus

The fact that the outer membrane of the nuclear envelope has bound ribosomes allows one to most reliably conclude that A) nuclear pore complexes contain proteins. B) the nuclear envelope is not part of the endomembrane system. C) at least some of the proteins that function in the nuclear envelope are made by the ribosomes on the nuclear envelope. D) the nuclear envelope is physically separated from the endoplasmic reticulum. E) small vesicles from the Golgi fuse with the nuclear envelope.

C) at least some of the proteins that function in the nuclear envelope are made by the ribosomes on the nuclear envelope.

Recent evidence shows that signals from the extracellular matrix (ECM) can regulate the expression of genes in the cell nucleus. A likely mechanism is that A) proteoglycans in the ECM undergo endocytosis and produce intracellular signaling molecules. B) intracellular signals might cause changes in the fibronectin binding to the cell surface. C) mechanical signals of the ECM can alter the cytoskeleton, which can alter intracellular signaling. D) orientation of microtubules to the ECM can change gene activity. E) integrins that receive signals from the ECM migrate to the nucleus.

C) mechanical signals of the ECM can alter the cytoskeleton, which can alter intracellular signaling.

Cytochalasin D is a drug that prevents actin polymerization. A cell treated with cytochalasin D will still be able to A) contract muscle fibers. B) form cleavage furrows. C) move vesicles around the cell. D) perform amoeboid movement. E) extend pseudopodia.

C) move vesicles around the cell.

Which of the following processes includes all of the others? A) transport of an ion down its electrochemical gradient B) osmosis C) passive transport D) facilitated diffusion

C) passive transport

Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules? A) glycogen B) lipids C) proteins D) cellulose E) nucleic acids

C) proteins

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

C) secondary, tertiary, and quaternary structures, but not primary structure

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) separate the major organelles so that their particular functions can be determined. D) separate lipid-soluble from water-soluble molecules. E) determine the size of various organelles.

C) separate the major organelles so that their particular functions can be determined.

Which type of organelle or structure is primarily involved in the synthesis of oils, phospholipids, and steroids? A) mitochondrion B) lysosome C) smooth endoplasmic reticulum D) ribosome E) contractile vacuol

C) smooth endoplasmic reticulum

A particular triplet of bases in the template strand of DNA is 5′-AGT-3′. What would be the corresponding codon for the mRNA that is transcribed? A) 3′-UGA-5′ B) 5′-TCA-3′ 3′-ACU-5′ Correct! 3′-UCA-5′

D) 3′-UCA-5′

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

D) 40

Which of the following statements concerning bacteria and archaea cells is correct? A) DNA is present in the mitochondria of both bacteria and archaea cells. B) Archaea cells contain a membrane-bound nucleus; bacteria do not. C) DNA is present in both archaea cells and bacteria cells. D) Archaea cells contain small membrane-enclosed organelles; bacteria do not.

D) Archaea cells contain small membrane-enclosed organelles; bacteria do not.

Which of the following is true when comparing an uncatalyzed reaction to the same reaction with a catalyst? A) The catalyzed reaction will be slower. B) The catalyzed reaction will consume all of the catalyst. C) The catalyzed reaction will have higher activation energy. D) The catalyzed reaction will have the same NJG.

D) The catalyzed reaction will have the same NJG.

The oxygen consumed during cellular respiration is directly involved in which of the following processes or events? A) glycolysis B) the oxidation of pyruvate to acetyl CoA C) the citric acid cycle D) accepting electrons at the end of the electron transport chain

D) accepting electrons at the end of the electron transport chain

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

D) always alter the primary structure of the protein, sometimes alter the tertiary structure of the protein, and affect its biological activity.

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

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

An animal cell lacking carbohydrates on the external surface of its plasma membrane would likely be impaired in which function? A) attaching the plasma membrane to the cytoskeleton B) establishing a diffusion barrier to charged molecules C) transporting ions against an electrochemical gradient D) cell-cell recognition

D) cell-cell recognition

A biologist ground up some plant leaf cells and then centrifuged the mixture to fractionate the organelles. Organelles in one of the heavier fractions could produce ATP in the light, whereas organelles in the lighter fraction could produce ATP in the dark. The heavier and lighter fractions are most likely to contain, respectively, A) chloroplasts and peroxisomes. B) mitochondria and chloroplasts. C) mitochondria and peroxisomes. D) chloroplasts and mitochondria. E) peroxisomes and chloroplasts.

D) chloroplasts and mitochondria

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

D) either hydroxyl or carboxyl groups

Plasmodesmata in plant cells are most similar in function to which of the following structures in animal cells? A) extracellular matrix B) tight junctions C) peroxisomes D) gap junctions E) desmosomes

D) gap junctions

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) central vacuole B) glyoxysome C) chloroplast D) lysosome E) peroxisome

D) lysosome

What types of proteins are not synthesized in the rough ER? A) endoplasmic reticulum proteins B) secreted proteins C) extracellular matrix proteins D) mitochondrial proteins E) plasma membrane proteins

D) mitochondrial proteins

Which plant cell organelle contains its own DNA and ribosomes? A) vacuole B) Golgi apparatus C) peroxisome D) mitochondrion E) glyoxysome

D) mitochondrion

Which of the following membrane activities requires energy from ATP hydrolysis? A) movement of carbon dioxide out of a paramecium B) facilitated diffusion of chloride ions across the membrane through a chloride channel 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 Na+ ions from a lower concentration in a mammalian cell to a higher concentration in the extracellular fluid

D) movement of Na+ ions from a lower concentration in a mammalian cell to a higher concentration in the extracellular fluid

Vinblastine, a drug that inhibits microtubule polymerization, is used to treat some forms of cancer. Cancer cells given vinblastine would be unable to A) extend pseudopods. B) migrate by amoeboid movement. C) maintain the shape of the nucleus. D) separate chromosomes during cell division. E) form cleavage furrows during cell division.

D) separate chromosomes during cell division.

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

D) unique three-dimensional shape of the fully folded polypeptide.

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

DNA duplexes will unwind and separate, and proteins will unfold (denature).

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

E) 10

The Golgi apparatus has a polarity or sidedness to its structure and function. Which of the following statements correctly describes this polarity? A) Transport vesicles fuse with one side of the Golgi and leave from the opposite side. B) Proteins in the membrane of the Golgi may be sorted and modified as they move from one side of the Golgi to the other. C) Soluble proteins in the cisternae (interior) of the Golgi may be sorted and modified as they move from one side of the Golgi to the other. D) Lipids in the membrane of the Golgi may be sorted and modified as they move from one side of the Golgi to the other. E) All of the above correctly describe polar characteristics of the Golgi function.

E) All of the above correctly describe polar characteristics of the Golgi function.

Green fluorescent protein (GFP) can be used to fluorescently label a specific protein in cells by genetically engineering cells to synthesize the target protein fused to GFP. What is the advantage of using GFP fusions to visualize specific proteins, instead of staining cells with fluorescently labeled probes that bind to the target protein? A) GFP permits the position of the protein in the cell more precisely than fluorescent probes. B) GFP fusions are not subject to artifacts; fluorescent probes may introduce background artifacts. C) GFP fusions enable higher resolution than staining with fluorescent probes. D) GFP permits visualization of protein-protein interactions; fluorescent probes do not. E) GFP fusions enable one to track changes in the location of the protein in living cells; staining usually requires preserved cells.

E) GFP fusions enable one to track changes in the location of the protein in living cells; staining usually requires preserved cells.

Why isn't the mitochondrion classified as part of the endomembrane system? A) It is not attached to the outer nuclear envelope. B) It has too many vesicles. C) It is not involved in protein synthesis. D) It is a static structure. E) Its structure is not derived from the ER or Golgi.

E) Its structure is not derived from the ER or Golgi.

Which of the following statements correctly describes some aspect of protein secretion from prokaryotic cells? A) Prokaryotes contain large pores in their plasma membrane that permit the movement of proteins out of the cell. B) Prokaryotes are unlikely to be able to secrete proteins because they lack an endomembrane system. C) In prokaryotes, the ribosomes that are used for the synthesis of secreted proteins are located outside of the cell. D) The mechanism of protein secretion in prokaryotes is probably the same as that in eukaryotes. E) Proteins that are secreted by prokaryotes are synthesized on ribosomes that are bound to the cytoplasmic surface of the plasma membrane.

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

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 is the fifth position on one of the nitrogenous bases. C) The 5' end has a carboxyl group attached to the number 5 carbon of ribose. D) The 5' end has phosphate attached to the number 5 carbon of the nitrogenous base. E) The 5' end has a phosphate group attached to the number 5 carbon of ribose.

E) The 5' end has a phosphate group attached to the number 5 carbon of ribose.

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

E) They have multiple double bonds in the carbon chains of their fatty acids.

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

E) a nitrogenous base, a phosphate group, and a pentose sugar

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

E) adding hydrogens and trans double bonds to the fatty acids

Which organelle or structure is absent in plant cells? A) microtubules B) peroxisomes C) Golgi vesicles D) mitochondria E) centrosomes

E) centrosomes

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

E) cytosine and uracil

Ions can travel directly from the cytoplasm of one animal cell to the cytoplasm of an adjacent cell through A) intermediate filaments. B) plasmodesmata. C) tight junctions. D) desmosomes. E) gap junctions.

E) gap junctions.

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

E) hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond