Cell Bio Exam I
Stage two of photosynthesis (or the light-independent reactions) uses which input molecules to produce organic food molecules? A) ATP, NADPH, CO2 B) O2, NADH, ADP C) H2O, light, chlorophyll D) amino acids, sugars, fatty acids
A) ATP, NADPH, CO2
Which of the following is a role that sugars can play outside of their role in energy production and storage? A) formation of support structures B) component of transport vesicle membrane C) enzymatic catalysis D) primary component of cell membrane
A) formation of support structures
Individuals with inherited diseases causing mitochondrial dysfunction typically experience which of the following symptoms? A) heart problems B) sterilit C) bone deformities D) light sensitivity
A) heart problems
Living systems can generate and maintain order without violating the second law of thermodynamics because they generate A) heat B) order C) decreased entropy D) macromolecules
A) heat
If a gene sequence in one organism is highly similar to the sequence of another gene in another organism it is called A) homologous B) related. C) protein-coding. D) comparative.
A) homologous
If a reaction is energetically favorable (exergonic), then it must produce a(n) A) increase in entropy. B) decrease in heat. C) increase in activation energy. D) decrease in reaction time.
A) increase in entropy.
The defining property that differentiates prokaryotic cells from eukaryotic cells is their A) lack of a nucleus B) presence of a flagellum C) small size D) cell division
A) lack of a nucleus
The cytochrome complexes contain heme prosthetic groups, which have a higher redox potential than the iron-sulfur centers found in other electron-transport chain complexes like NADH dehydrogenase. Where in the electron-transport chain would the cytochrome complexes thus be located relative to iron-sulfur center complexes? A) later in the chain B) earlier in the chain C) It cannot be determined. D) at the same point of the chain
A) later in the chain
Covalent bonds in macromolecules are primarily important for A) linking together monomers. B) forming the three-dimensional folded conformation. C) interactions with other macromolecules. D) enzyme-substrate binding.
A) linking together monomers.
A binding site on the surface of a protein interacts specifically with another protein through A) many weak noncovalent interactions. B) a few strong noncovalent interactions. C) many weak covalent interactions. D) a few strong covalent interactions.
A) many weak noncovalent interactions.
Compared to eukaryotes, prokaryotic organisms are A) more abundant and more widespread B) less abundant and less widespread C) more abundant and less widespread D) less abundant and more widespread
A) more abundant and more widespread
Lysosomes and Peroxisomes both perform a series of reactions to break down molecules, but one difference between them is that A) peroxisomes contain hydrogen peroxide B) lysosomes break down toxic molecules C) peroxisomes digest molecules for reuse D) lysosomes are large and form an interconnected network
A) peroxisomes contain hydrogen peroxide
How is pyruvate imported into the mitochondrial matrix for use in the citric acid cycle? A) proton gradient-driven symport B) sodium gradient-driven antiport C) ATP-driven pyruvate pump D) diffusion through porin complexes in the membrane
A) proton gradient-driven symport
In an enzymatic reaction, a molecule gains an electron. This is known as a(n) ___________ reaction. A) reduction B) oxidation C) hydrogenation D) electronegative
A) reduction
Two atoms held together solely by ionic bonds are referred to as a(n) A) salt. B) molecule. C) element. D) isotope.
A) salt.
All living cells A) share the same basic chemistry B) have the same overall shape C) are nearly the same size D) need to replicate within another cell
A) share the same basic chemistry
If cells that cannot carry out fermentation were grown in anaerobic conditions, at which step would glycolysis halt? A) step 6: where NAD+ is converted to NADH B) step 1: using ATP to phosphorylate glucose C) step 10: production of pyruvate D) step 4: the cleavage of the 6-carbon molecule into two 3-carbon molecules
A) step 6: where NAD+ is converted to NADH
Which of the following is an inorganic compound? A) table salt (e.g., NaCl) B) simple sugars (e.g., glucose) C) amino acids (e.g., phenylalanine) D) saturated fatty acids (e.g., palmitic acid)
A) table salt (e.g., NaCl)
The low redox potential of NADH means that it has a A) tendency to give up electrons. B) low free energy. C) high electron affinity. D) very stable bond.
A) tendency to give up electrons.
What is gluconeogenesis? A) the synthesis of glucose from pyruvate B) the mobilization of glucose from glycogen stores C) the production of glucose from starch D) the blockage of glycolysis at the first step
A) the synthesis of glucose from pyruvate
The cell components that move materials from one organelle to another are called A) transport vesicles B) endoplasmic reticulum C) Golgi apparatus D) cytosol
A) transport vesicles
The function of feedback inhibition of an enzymatic pathway is to A) turn off synthesis of a product when it is in abundance. B) accumulate large amounts of important biological molecules. C) irreversibly shut down a biosynthetic pathway. D) increase concentrations of intermediates to drive the reaction forward.
A) turn off synthesis of a product when it is in abundance.
If protein folding is determined by the sequence of amino acids in the polypeptide chain, why are chaperone proteins needed to assist folding in the cell? A) Some proteins cannot fold on their own. B) Certain proteins easily aggregate with other proteins. C) Proteins constantly unfold and refold. D) Protein folding is energetically unfavorable.
B) Certain proteins easily aggregate with other proteins.
Which of the following techniques of microscopy allows the observation of living cells (i.e. NOT fixed cells) ? A) scanning electron microscopy B) fluorescent microscopy C) transmission electron microscopy D) There are no microscopy techniques suitable for the observation of living cells
B) fluorescent microscopy
The inner membrane of the mitochondrion appears ________ because it provides __________. A) smooth; a smaller surface for the organization of proteins in respiration B) folded; a large surface area for staging energy production processes C) smooth; a large surface area for staging energy production processes D) folded; a smaller surface area for the organization of proteins in respiration
B) folded; a large surface area for staging energy production processes
A base is a molecule that will ___________ a proton in water. A) accept B) donate C) repel D) neutralize
A) accept
What is one of the main differences between DNA and RNA? A) DNA uses four different bases than RNA does. B) RNA has two hydroxyl groups on the sugar, DNA has one. C) DNA has three phosphate groups, RNA has one. D) RNA does not contain the base cytosine.
B) RNA has two hydroxyl groups on the sugar, DNA has one.
Amino acids with side chains that contain −COOH groups, like those shown below, would be ___________ in the aqueous environment of a cell. A) nonpolar B) acidic C) basic D) hydrophobic
B) acidic
What is the fermentation product produced in an anaerobic muscle cell? A) ethanol B) lactic acid C) 1 ATP D) 1 ADP
B) lactic acid
The rules of which fundamental process were elucidated in the bacterium Escherichia coli (E. coli)? A) DNA Replication B) cell division cycle C) mitosis D) embryonic development
A) DNA Replication
The food molecule whose breakdown generates most of the energy for a majority of animal cells is A) sucrose B) glucose C) fat D) protein
B) glucose
Glycogen synthetase enzyme, which forms glycogen from glucose, is activated by excess A) ATP. B) glucose 6-phosphate. C) phosphate. D) pyruvate.
B) glucose 6-phosphate
Biochemical subcompartments that form inside the nucleus are distinct from their immediate surroundings because of the A) formation of a lipid membrane. B) high concentrations of interacting proteins and RNA. C) fusion of oil droplets. D) disassembly of scaffold proteins.
B) high concentrations of interacting proteins and RNA.
Which of the following occurs by bringing nonpolar surfaces together to exclude water? A) hydrogen bonds B) hydrophobic forces C) Van der Waals attractions D) electrostatic attractions
B) hydrophobic forces
When a ligand binds to an allosteric enzyme's regulatory site, it changes the activity of that enzyme by A) directly blocking the active site. B) inducing a conformational change. C) acting as a chaperone. D) denaturing the enzyme.
B) inducing a conformational change.
Protons are pumped across the mitochondrial inner membrane to accumulate in the A) mitochondrial matrix. B) intermembrane space. C) cytosol. D) electron-transport chain.
B) intermembrane space.
Enzymes increase the speed of a chemical reaction because they A) increase the temperature to provide the necessary boost of energy. B) lower the activation energy needed to start the reaction. C) make the reaction more energetically favorable. D) make the reaction spontaneous.
B) lower the activation energy needed to start the reaction.
Which of the following is a role of the cytoskeleton in plant cells? A) Intermediate filaments support chloroplast structure. B) Actin filaments guide cell movement. C) Microtubules form tracks for movement of cell components. D) Intermediate filaments form strong links to the plant cell wall.
C) Microtubules form tracks for movement of cell components.
How do the high-energy electrons of activated carriers contribute to forming the high-energy phosphate bonds of ATP? A) They are transferred directly to ADP to form ATP. B) They are passed to ATP synthase to power ATP synthesis. C) They are used by the electron-transport chain to make a proton gradient. D) They are pumped across the membrane to form an electron gradient.
C) They are used by the electron-transport chain to make a proton gradient.
Which of the following is true about amyloid protein structures? A) They always cause neurogenerative diseases. B) They are weak and brittle. C) They consist of stacked β sheets. D) They are made up of helical protein fibers.
C) They consist of stacked β sheets.
The genes in the genome of an adult organism A) must all be expressed in all the cells of the organism for survival B) are mostly silenced after embryonic development is complete C) are expressed or silenced depending on whether a gene is needed in that cell type and environment D) are vastly different in composition depending on the cell type
C) are expressed or silenced depending on whether a gene is needed in that cell type and environment
A segment of DNA in the genome that is not a protein-coding gene A) is junk DNA left over from mistakes in evolution. B) is completely unimportant to the cell. C) can be used to regulate gene activity. D) must encode a functional RNA.
C) can be used to regulate gene activity.
Cellular respiration ___________ energy and produces ___________, whereas photosynthesis ___________ energy and produces ___________. A) consumes; oxygen + sugars; produces; water + carbon dioxide B) produces; oxygen + sugars; consumes; water + carbon dioxide C) consumes; water + carbon dioxide; produces; oxygen + sugars D) produces; water + carbon dioxide; consumes; oxygen + sugars
C) consumes; water + carbon dioxide; produces; oxygen + sugars
Which type of noncovalent interaction can involve either the polypeptide backbone or amino acid side chains? A) van der Waals attractions B) hydrophobic forces C) hydrogen bonds D) electrostatic interactions
C) hydrogen bonds
Strong and specific associations between macromolecules or between an enzyme and its substrate are due to A) many strong covalent bonds. B) few strong covalent bonds. C) many weak noncovalent bonds. D) many strong noncovalent bonds.
C) many weak noncovalent bonds.
The proton flow through the transmembrane H+ carrier of ATP synthase results in A) bending of the carrier and stalk to produce mechanical force. B) moving ADP and Pi across the membrane into the enzyme active site. C) mechanical rotation that is converted into the chemical-bond energy of ATP. D) binding of the proton to ADP to enhance formation of the phosphate bond.
C) mechanical rotation that is converted into the chemical-bond energy of ATP.
If the products of a reaction have more free energy than the reactants, then that reaction is A) spontaneous. B) energetically favorable. C) not energetically favorable. D) physically impossible.
C) not energetically favorable.
Self-replication of living cells occurs through the catalytic action of A) DNA B) RNA C) proteins D) nucleotides
C) proteins
Chlorophyll appears green because it __________ light. A) absorbs blue light. B) absorbs red light. C) reflects green light. D) reflects UV light.
C) reflects green light.
Chemical modifications like phosphorylation and acetylation of proteins occur on ___________ of amino acids and can affect interaction of proteins with other cell components or structures. A) amino groups B) carboxyl groups C) side chains D) peptide groups
C) side chains
Gluconeogenesis requires a total of ___________ ATP and GTP molecules combined. A) two B) four C) six D) eight
C) six
Glycolysis produces ___________ ATP molecules, whereas the complete oxidation of glucose to water and carbon dioxide produces ___________ ATP molecules. A) two; ten B) four; thirty-four C) two; thirty D) four; twenty
C) two; thirty
What is the value of ΔG at equilibrium? A) zero B) positive C) negative D) It depends on the concentration of substrates and products.
A) zero
The number of ATP molecules that could be synthesized from the energy released by the transfer of two electrons from NADH to molecular oxygen is A) 2.5. B) 4. C) 3 D) 1.5
A) 2.5.
The pH of the mitochondrial matrix is ___________, which is ___________ than that of the intermembrane space. A) 7.9; higher B) 7.2; lower C) 7.2; higher D) 7.9; lower
A) 7.9; higher
Glycolysis alone captures approximately what percentage of the free energy available in a molecule of glucose? A) 10% B) 20% C) 50% D) 99%
A) 10%
Why do cells use enzymes to harvest energy from food molecules rather than by direct oxidation? A) Enzymes transfer energy from food to carrier molecules in small steps. B) Enzymes release all the energy from food molecules in a single efficient step. C) Direct oxidation cannot release all the energy from food molecules D) Direct oxidation is energetically unfavorable.
A) Enzymes transfer energy from food to carrier molecules in small steps.
Which of the following has a higher concentration in the cell to allow it to be available to accept electrons from oxidation of food molecules? A) NAD+ B) NADH C) NADPH D) NADP+
A) NAD+
If cells were undergoing glycolysis but could not carry out fermentation, what products would build up in the cytosol? A) NADH and pyruvate B) ADP and CO2 C) H2O and citric acid D) NAD+ and ATP
A) NADH and pyruvate
Which of the following has the lowest electron affinity? A) NADH dehydrogenase complex B) cytochrome c reductase complex C) cytochrome c oxidase complex D) oxygen
A) NADH dehydrogenase complex
Which of the following microscopy techniques would allow the most detailed image showing the 3D structure of flagellum? A) scanning electron microscopy B) transmission electron microscopy C) high-resolution fluorescence microscopy D) conventional light microscopy
A) Scanning electron microscopy
For a reaction Y à X with a very high equilibrium constant, K, which of the following is true? You can refer to the following two equations in formulating your answer. A) The amount of product will be higher than the amount of substrate at equilibrium. B) The forward reaction rate greatly exceeds the reverse reaction rate at equilibrium. C) The standard free-energy change is large and positive. D) The amount of product and substrate are equal at equilibrium.
A) The amount of product will be higher than the amount of substrate at equilibrium.
In a sperm cell, where are the mitochondria located? A) The mitochondria form elongated tubes that wrap around the flagellar core. B) They are located in a tubular network that are just inside the plasma membrane. C) Mitochondria are randomly scattered around in the cytoplasm of the cell. D) The mitochondria surround the nucleus of the cell.
A) The mitochondria form elongated tubes that wrap around the flagellar core.
Why is the oxidation of NADPH energetically favorable? A) The oxidized form of NADPH is more stable than the reduced form. B) NADPH is the form of the molecule that can gain two high-energy electrons. C) The biosynthetic reactions that are coupled to NADPH oxidation are energetically favorable. D) Oxidation of NADPH breaks a high-energy phosphoanhydride bond.
A) The oxidized form of NADPH is more stable than the reduced form.
Shown below is the mechanism believed to be used for pumping protons by cytochrome c oxidase across the inner mitochondrial membrane. One of the steps shown is unidirectional because it is driven by the energy of electron transport. Why must this step be performed only in one direction? A) The protons could be also captured from the intermembrane space and released back into the matrix. B) The complex would stay stuck in the closed (center conformation). C) The inner membrane would become porous to all molecules. D) The H+ affinity in the two conformations would reverse.
A) The protons could be also captured from the intermembrane space and released back into the matrix.
The first living things on Earth probably generated ATP by what mechanism? A) fermentation B) oxidative phosphorylation C) photosynthesis D) carbon fixation
A) fermentation
Fatty acids can be used to produce energy by conversion to ___________ in the ___________ of the cell. A) acetyl CoA; mitochondria B) pyruvate; endoplasmic reticulum C) lipids; plasma membrane D) NADH; cytosol
A) acetyl CoA; mitochondria
How does binding of GTP to a GTP-binding protein affect its activity? A) always activates the protein B) always inactivates the protein C) does not affect the protein D) could activate or inactivate the protein
A) always activates the protein
Reactions that build larger molecules in the cell are called ___________; reactions that break down molecules into smaller ones are called ___________. A) anabolic; catabolic B) catabolic; anabolic C) anabolic; metabolic D) metabolic; anabolic
A) anabolic; catabolic
A molecule with a lot of polar covalent bonds is likely to A) be highly soluble in water. B) be hydrophobic. C) form ionic bonds. D) contain only atoms with low electronegativity.
A) be highly soluble in water.
Why is CO2 an end product of cellular respiration? A) because it is the most stable form of carbon in our atmosphere B) because it can accept electrons and produce a reduced form of carbon C) because it captures light energy for photosynthesis D) because plants can use it for respiration
A) because it is the most stable form of carbon in our atmosphere
All amino acids have which of the following chemical groups in common? A) carboxyl group B) aromatic ring group C) methyl group D) hydrocarbon tail
A) carboxyl group
Long polymers are made from single subunits in cells using a ___________ reaction, which ___________ water. A) condensation; releases B) hydrolysis; uses C) condensation; uses D) hydrolysis; releases
A) condensation; releases
Disulfide bonds stabilize protein shape outside the cell by A) covalent bonds between cysteines. B) noncovalent bonds between charged side chains. C) hydrophobic interactions within the lipid bilayer. D) hydrogen bonds with water molecules.
A) covalent bonds between cysteines.
A stretch of amino acids in a polypeptide chain that is capable of independently folding into a defined structure is called a A) domain B) backbone C) subunit D) ligand
A) domain
What is the role of oxygen in the electron transport chain? A) electron acceptor B) coenzyme C) reducing agent D) transporter
A) electron acceptor
Each molecule of acetyl-CoA entering the citric acid cycle produces two ___________ and four ___________. A) NADH; ATP B) CO2; activated carriers C) ATP; GTP D) activated carriers; H2O
B) CO2; activated carriers
Glucose has a molecular weight of 180 grams per mole. To prepare 1 liter of a 100 mM solution, how many grams of glucose would you dissolve in water for a total volume of 1 liter? A) 180 B) 18 C) 1.8 D) 1800
B) 18
The major products of the citric acid cycle are A) pyruvate and ATP. B) CO2 and NADH. C) H2O and ATP. D) NADH and ATP.
B) CO2 and NADH.
Cytochrome c oxidase catalyzes the reaction that reduces molecular oxygen (two oxygen atoms) to two water molecules. The electrons are added sequentially, and during the process cytochrome c oxidase must bind the oxygen tightly in the active site. Why? A) If the oxygen escapes, it will bubble out as a gas and escape quickly. B) Superoxide radicals are formed as an intermediate, and are dangerous to the cell. C) Oxygen will bind to the electron-transport chain and reverse the pumping of protons. D) The escaped oxygen will form carbon monoxide and kill the cell.
B) Superoxide radicals are formed as an intermediate, and are dangerous to the cell.
Which of the following is a reason why ATP hydrolysis has a negative ΔG0? A) ATP has a high concentration in cells. B) The removal of the phosphate is energetically favorable. C) The reverse reaction is extremely fast. D) The products have more free energy than the reactants.
B) The removal of the phosphate is energetically favorable. -The products of the ATP hydrolysis reaction—ADP and free phosphate—are more stable and have a lower free energy. Release of free phosphate is energetically favorable because it relieves the repulsion of the negative charges of the neighboring phosphate groups and the aqueous environment to make hydrogen bonds with the phosphate.
What is the role of activated carriers in cells? A) They are enzymes that catalyze biosynthetic reactions and make them feasible at the temperature of a cell. B) They capture energy from energy releasing reactions and transfer it to other reactions. C) They are enzymes that catalyze the reactions that break down foodstuffs for energy generation in the cell. D) They carry energy from anabolic reactions for use in catabolic reactions.
B) They capture energy from energy releasing reactions and transfer it to other reactions. - Activated carriers collect electrons from oxidation of molecules in catabolic reactions and transfer them to anabolic reactions that require electrons for the reduction of molecules.
Why is sunlight the ultimate source of energy for nearly all living things on Earth? A) because the Earth makes a full rotation on it's axis, which provides light once a day B) because photosynthetic organisms produce food molecules using light energy C) because animals obtain heat energy from the sun, which keeps them alive D) because all animals must consume plants for obtaining energy
B) because photosynthetic organisms produce food molecules using light energy
Why is the presence of oxygen required for the citric acid cycle to operate? A) because oxygen combines with carbon from acetyl CoA to form the citric acid product CO2 B) because the NADH passes its electrons to oxygen in the electron transport chain to renew NAD+ C) because oxygen oxidizes several enzymes in the citric acid cycle D) because oxygen forms the water that is used in hydrolysis reactions in the citric acid cycle
B) because the NADH passes its electrons to oxygen in the electron transport chain to renew NAD+
In oxidative phosphorylation in mitochondria, high-energy electrons are transferred to the electron-transport chain from activated carriers like NADH. Stage 1 of photosynthesis also uses an electron-transport chain to pump protons and make ATP. In this case, where do the high-energy electrons come from? A) NADPH B) chlorophyll C) ADP D) FADH2
B) chlorophyll
Which of the following shows protein organizational units in the correct order from smallest to largest? A) subunit < domain < complex B) domain < subunit < complex C) complex < domain < subunit D) complex < subunit < domain
B) domain < subunit < complex
Which of the following accurately matches the types of filaments in the cytoskeleton with their cellular function? A) microtubules—cell movement; intermediate filaments—chromosome segregation; actin filaments—strength/support B) microtubules—chromosome segregation; intermediate filaments—strength/support; actin filaments—cell movement C) microtubules—cell movement; intermediate filaments—strength/support; actin filaments—chromosome segregation D) microtubules—strength/support; intermediate filaments—cell movement; actin filaments—chromosome segregation
B) microtubules—chromosome segregation; intermediate filaments—strength/support; actin filaments—cell movement
The Golgi apparatus' main function is to A) make proteins for secretion B) package and modify proteins for secretion
B) package and modify proteins for secretion
A nucleotide is different from a nucleoside because a nucleotide has a A) nitrogen-containing base B) phosphate group(s) C) ribose sugar. D) deoxyribose sugar.
B) phosphate group(s)
A readily available source of energy that cells use to drive reactions is stored in the ___________ bond. A) phosphodiester B) phosphoanhydride C) hydrogen D) peptide
B) phosphoanhydride
What is the name used for a molecule in which two carbons of glycerol are attached to fatty acid chains, and the third carbon is attached to a phosphate group? A) triacylglycerol B) phospholipid C) steroid D) amphipathic
B) phospholipid
The first step of glycolysis uses one ATP molecule in order to A) transport glucose. B) phosphorylate glucose. C) breakdown sucrose. D) store glucose.
B) phosphorylate glucose.
One piece of evidence indicating that chloroplasts evolved from engulfed photosynthetic bacteria is A) the presence of chlorophyll B) that they contain their own DNA C) the folded membrane D) that mitochondria were already present in the cell
B) that they contain their own DNA
The Michaelis constant (KM) of an enzyme is a measure of A) the rate at which the enzyme converts the substrate to product. B) the binding strength of enzyme to substrate. C) the energetic favorability of the reaction. D) the activation energy.
B) the binding strength of enzyme to substrate.
Archaea and bacteria are two separate domains of prokaryotes that were distinguished by examining A) their cell structures B) their DNA sequences C) the presence vs. absence of a nucleus D) the presence vs. absence of chloroplasts
B) their DNA sequences
The photosynthetic machinery is found in which of the compartments A) stroma B) thylakoid membrane C) inner membrane D) outer membrane
B) thylakoid membrane
What is the function of a kinase? A) to oxidize a molecule B) to add a phosphate group to a molecule C) to rearrange the bonds into an isomeric form D) to shift a chemical group from one position to another in a molecule
B) to add a phosphate group to a molecule
During glycolysis, the number of ATP consumed (per glucose molecule) is ___________, while the number produced is ___________. Group of answer choices A) one; two B) two; four C) six; thirty-six D) four; two
B) two; four
The technique that scientists used to determine that hemoglobin was a single large macromolecule rather than a loose conglomeration of small organic molecules was A) electron microscopy. B) ultracentrifugation. C) DNA sequencing. D) hydrolysis.
B) ultracentrifugation.
Which of the following is UNLIKELY to be hydrophilic? A) a salt that is held together with ionic bonds B) a molecule with a lot of polar covalent bonds C) a molecule with primarily nonpolar covalent bonds D) a molecule that forms hydrogen bonds with water
C) a molecule with primarily nonpolar covalent bonds
What is a protein family? A) a set of proteins that have the same number of domains B) a group of proteins from unrelated species C) a structurally related group of proteins D) a collection of proteins that have all been crystallized
C) a structurally related group of proteins
Which method is used for separating proteins based on specific interactions with other molecules? A) mass spectrometry B) gel electrophoresis C) affinity chromatography D) x-ray crystallography
C) affinity chromatography
A folded protein structure with which free-energy (G) value would likely have the most stable conformation? A) 10 B) 5 C) 15 D) 1
D) 1
In the presence of high levels of ___________, the enzyme phosphofructokinase is inhibited. A) glucose B) ADP C) fructose D) ATP
D) ATP
Hydrogen bonding between N-H and C=O groups of every fourth amino acid within a polypeptide chain results in which type of folding pattern? A) antiparallel β sheet (A) B) parallel β sheet (B) C) amyloid structure (C) D) α helix (D)
D) α helix (D)
Which of the following is INCORRECT regarding how enzymes lower the activation energy of a reaction? A) Enzymes encourage the substrates to change shape toward a transition state that favors the reaction B) Enzymes align substrates to promote a reaction between them. C) Enzymes rearrange electrons in the substrates in a way that favors the reaction. D) Enzymes reduce the free energy of the products of the reaction.
D) Enzymes reduce the free energy of the products of the reaction.
The citric acid cycle produces which activated carriers that transfer high-energy electrons to the electron-transport chain? A) NADPH and NADH B) NAD+ and FAD C) NADP and FAD D) NADH and FADH2
D) NADH and FADH2
The chemical reactions that take place in a cell, as compared to the chemistry in nonliving matter, primarily occur A) between simple molecules. B) in a hydrophobic environment. C) in extreme temperatures. D) between carbon-based molecules.
D) between carbon-based molecules.
Mistakes in replicating the DNA of a cell before cell division A) have no consequence of the cell's survival B) always lead to reduced survival of the cell C) lead to increased survival of the cell D) can have positive, negative, or neutral effects
D) can have positive, negative, or neutral effects
How does phosphorylation of a protein affect its activity? A) always increases activity B) always decreases activity C) never affects activity D) could increase or decrease activity
D) could increase or decrease activity
Which method is most suitable for determining the three-dimensional structure of an extremely large integral membrane protein complex? A) NMR spectroscopy B) mass spectrometry C) x-ray crystallography D) cryoelectron microscopy
D) cryoelectron microscopy
The main function of the nucleus is to A) provide energy for the cell B) allow cells to segregate their chromosomes C) make proteins using the genetic material D) house the DNA in a separate cell compartment
D) house the DNA in a separate cell component
The fruit fly, Drosophila melanogaster (D. melanogaster) is an excellent model for studying fundamentals of development because A) the precise formation of each of their 959 body cells has been mapped. B) they are transparent and allow visualization of cell division and movement. C) they reproduce every 30 minutes on a plate. D) many of the genes involved in the development of the fruit fly are also found in humans.
D) many of the genes involved in the development of the fruit fly are also found in humans.
Which of the following chemical groups could confer nonpolar/hydrophobic characteristics on the region of a molecule in which it is found? A) phosphate groups (−PO32-) B) carboxyl group (−COOH) C) amino group (−NH2) D) methyl group (−CH3)
D) methyl group (−CH3)
The function of a _______ cell, which has a long, branched structure, requires many connections to be made with neighboring cells? A) egg B) fat C) yeast D) nerve
D) nerve
Which of the following correctly matches the cellular location with the production of ATP by oxidative phosphorylation in that cell type? A) chloroplasts—plants B) mitochondria—archaea C) cell wall—photosynthetic algae D) plasma membrane—bacteria
D) plasma membrane—bacteria
Which of the following levels of protein structure involves the interaction of more than one polypeptide chain into a three-dimensional structure? A) primary B) secondary C) tertiary D) quaternary
D) quaternary
In addition to being converted to acetyl CoA for the citric acid cycle, pyruvate made during glycolysis can be used for A) membrane transport. B) synthesis of alanine. C) fermentation. D) synthesis of alanine and fermentation.
D) synthesis of alanine and fermentation.
Which of the following is a mobile electron carrier in the electron-transport chain? A) NADH dehydrogenase complex B) cytochrome c reductase complex C) cytochrome c oxidase complex D) ubiquinone
D) ubiquinone; also cytochrome c
Condensation reactions are energetically ___________ and hydrolysis reactions are energetically ___________. A) unfavorable; unfavorable B) favorable; favorable C) favorable; unfavorable D) unfavorable; favorable
D) unfavorable; favorable
Ionic bonds are ___________ than covalent bonds and are ___________ common in cells. A) stronger; more B) stronger; less C) weaker; more D) weaker; less
D) weaker; less
What is the relationship between ΔG and ΔG0? A) ΔG0 is the free-energy change at standard temperature. B) ΔG0 is the free-energy change at standard pressure. C) ΔG0 is the free-energy change at standard concentrations. D) ΔG0 is the free-energy change at standard temperature and concentrations.
D) ΔG0 is the free-energy change at standard temperature and concentrations.
