BMB 322: FINAL EXAM
In glycolysis, ATP molecules are produced by _____.
substrate-level phosphorylation
Calculate ΔG for ATP hydrolysis in a cell at 37 ∘C that contains [ATP]=3mM, [ADP]=1mM, and [Pi]=1mM.
-51.1 kJ/mol
Glycolysis and gluconeogenesis are opposed pathways in that they begin or end with the same metabolites and share common intermediates and/or enzymes. Yet, for energetic reasons, the two processes cannot be the exact reverse of each other. How is this possible? 1) Because not every intermediate or enzyme participates in both pathways, conditions will dictate which pathway is stimulated while the other is inhibited. 2) Levels of ATP will dictate which pathway is operational. 3) Both pathways make use of substrate cycles.
1) Because not every intermediate or enzyme participates in both pathways, conditions will dictate which pathway is stimulated while the other is inhibited. 2) Levels of ATP will dictate which pathway is operational. 3) Both pathways make use of substrate cycles.
Which of the following statements about metabolism are true? 1) Catabolism is the process in which complex substances are broken down, yielding a net output of energy. 2) Metabolism is an integrated system in which many of the same reactions participate in degradative (catabolic) and biosynthetic (anabolic) pathways. 3) Anabolism involves the synthesis of polymeric biomolecules and complex lipids from monomers such as fatty acids and nucleotides. 4) All organisms derive raw materials and energy from organic molecules, such as glucose.
1) Catabolism is the process in which complex substances are broken down, yielding a net output of energy. 2) Metabolism is an integrated system in which many of the same reactions participate in degradative (catabolic) and biosynthetic (anabolic) pathways. 3) Anabolism involves the synthesis of polymeric biomolecules and complex lipids from monomers such as fatty acids and nucleotides.
The combustion of glucose ultimately involves the transfer of electrons to oxygen (O2). In biological systems, this takes place without a large increase in temperature. Which of the following statements about this process in biological systems is true? 1) Coupled oxidation-reduction reactions occur with electrons being passed to intermediate electron carriers. 2) The process involves the transfer of 12 pairs of electrons to oxygen. 3) The transfer of electrons from intermediate electron carriers to molecular oxygen is catalyzed by the electron transport chain. 4) Though the process is a controlled oxidation, some energy is lost.
1) Coupled oxidation-reduction reactions occur with electrons being passed to intermediate electron carriers. 2) The process involves the transfer of 12 pairs of electrons to oxygen. 3) The transfer of electrons from intermediate electron carriers to molecular oxygen is catalyzed by the electron transport chain. 4) Though the process is a controlled oxidation, some energy is lost.
Under certain circumstances, glycolysis takes place in the absence of oxygen. When this happens, which of the following products may be produced? 1) lactate 2) ethanol 3) carbon dioxide 4) acetyl CoA
1) lactate 2) ethanol 3) carbon dioxide
Describe the predominant character of the following polypeptides using the following options (A) Nonpolar (B) Polar Uncharged (C) Polar Postively charged (D) Polar Negatively Charged 10) STCQTSNQ 11) LIVGPGAMI 12) RKSNRHKH 13) EYKDEDER
10)(B) Polar Uncharged 11) (A) Nonpolar 12) (C) Polar Postively charged 13) (D) Polar Negatively Charged
How many NADH are produced by glycolysis?
2
In glycolysis there is a net gain of _____ ATP.
2
For each glucose that enters glycolysis, _____ acetyl CoA enter the citric acid cycle.
2 Each glucose produces two pyruvates, each of which is converted into acetyl CoA.
Which of the following citric acid intermediates is(are) not used in the preparation of the products shown? 1) citrate ⟶ fatty acids, steroids 2) alpha-ketoglutarate ⟶ steroids 3) oxaloacetate ⟶ purines, pyrimidines 4) alpha-ketoglutarate ⟶ heme
2 & 4 are incorrect
Which of the following statements about ATP are true? 1) ATP has reactive phosphoester bonds. 2) ATP has a high Eact for hydrolysis with water. 3) ATP is kinetically stable but thermodynamically unstable. 4) ATP spontaneously phosphorylates other molecules because it has a high group transfer potential.
2) ATP has a high Eact for hydrolysis with water. 3) ATP is kinetically stable but thermodynamically unstable.
Which of the following four statements is/are accurate with respect to glycolysis? 1) Glycolysis involves the conversion of monosaccharides into glucose. 2) Glycolysis involves the breakdown of glucose into glyceraldehyde-3-phosphate. 3) Glycolysis involves the conversion of pyruvate into glucose to glyceraldehyde-3-phosphate. 4) Glycolysis involves the conversion of pyruvate into acetyl CoA.
2) Glycolysis involves the breakdown of glucose into glyceraldehyde-3-phosphate.
Calculate the oxidation energy in term of kJ/mol for glucose.
2815 kJ/mol
Which of the following are nucleophiles? 1) protonated imine 2) carbonyl group 3) carboxylate 4) imidazole
3) carboxylate 4) imidazole
In some instances, the levels of LDL cholesterol exceed the ability of the body to maintain homeostasis, and as a result, the excess material accumulates into fatty deposits that harden into plaques. Arrange in the correct order the sequence of events that leads to this condition, known as atherosclerosis: 1) The plaques harden, blocking the flow of blood in major arteries. 2) White blood cells become engorged with fatty deposits. 3) Excess LDL cholesterol accumulates in the interior of arterial walls. 4) Macrophages are drawn to this site.
3,4,2,1
Arrange the order of events in the fatty acid (FA) metabolism pathway in the correct order: 1) The modified FA is transported across the inner membrane of the mitochondrion. 2) Dehydration occurs to generate an α,β-unsaturated FA. 3) The free FA is converted to acetyl CoA ester. 4) Thiolytic cleavage occurs, releasing a molecule of acetyl CoA and a new FA with two fewer carbon atoms. 5) The FA CoA ester is converted to its carnitine ester. 6) Hydration occurs to yield a β-hydroxy ester. 7) The FA CoA ester is regenerated.
3,5,1,7,2,6,4
In the conversion of ethanol to acetaldehyde with concomitant conversion of NAD+ to NADH, which of the following statements is true? 1) Ethanol is the oxidant. 2) NAD+ is the reductant. 3) Acetaldehyde accepts electrons. 4) Ethanol gives up electrons.
4) Ethanol gives up electrons.
Arrange the sequence of events for the overall mitochondrial respiratory assembly in the correct order. 1) Coenzyme Q-cytochrome c reductase passes electrons to cytochrome c. 2) Coenzyme Q releases its electrons to complex III. 3) Cytochrome oxidase catalyzes the reduction of O2 to water. 4) Succinate, through complex II, and NADH, via complex I, release electrons to coenzyme Q.
4,2,1,3
The β-oxidation of odd-numbered FAs presents a small problem in that once most of the oxidation has occurred, the last component is propionyl-CoA rather than acetyl CoA. This has one more carbon and as such cannot be utilized any further. Outline the events that control the metabolism of this unit in their proper order: 1) Methylmalonyl-CoA epimerase converts S-methylmalonyl-CoA to R-methylmalonyl-CoA. 2) Methylmalonyl-CoA mutase demethylates R-methylmalonyl-CoA to succinyl-CoA. 3) Propionyl-CoA carboxylase catalyzes the addition of CO2 to propionyl-CoA. 4) The odd-carbon FA is metabolized to propionyl-CoA.
4,3,1,2
Calculate the oxidation energy in term of kJ per carbon atom oxidized for glucose.
469.2 kJ/mol of C
For each glucose that enters glycolysis, _____ NADH + H+ are produced by the citric acid cycle.
6 3 NADH + H+ are produced per each acetyl CoA that enters the citric acid cycle.
Describe the predominant character of the following polypeptides using the following options A) Nonpolar B) Polar Uncharged C) Polar Positively charged D) Polar Negatively Charged 6) DETDDESD 7) RKLGRHKK 8) GVALPIVAL
6) D 7) C 8) A
Calculate the oxidation energy in term of kJ per carbon atom oxidized for palmitic acid.
622.4 kJ/mol of C
Calculate the oxidation energy in term of kJ/mol for palmitic acid.
9958 kJ/mol
Put the following molecules in order of increasing affinity for Oxygen: R-State Hemoglobin, T-state State Hemoglobin, Myoglobin A) T-state Hemoglobin, R-State Hemoglobin, Myoglobin B) Myoglobin, R-State Hemoglobin, T-State Hemoglobin C) R-state Hemoglobin, Myoglobin, T-State Hemoglobin D) Myoglobin, T-State Hemoglobin, R-State Hemoglobin E) R-State Hemoglobin, T-State Hemoglobin, Myoglobin
A) T-state Hemoglobin, R-State Hemoglobin, Myoglobin
How many electrons must an electron carrier be able to move in a single reaction in order to reduce molecular oxygen? A) 1 electron B) 2 electrons C) 3 electrons D) 2 electrons, but they must come with Hydrogen
A) 1 electron
If the ΔG°' for the hydrolysis of ATP to ADP is -30.5 kJ/mol, what is the Keq at 37°C? A) 1.38 x 10^5 B) 7.30x10^-6 C) 6.76 x 10^11 D) 1.48 x 10^-12 E) 11.83 x 10^0
A) 1.38 x 10^5
Serine has a M.W. of 105, Tyrosine has a M.W. of 181, and Glutamine has a M.W. of 146. What is the M.W. of the polypeptide, QYQS? A) 524 B) 578 C) 613 D) 559 E) 542
A) 524
Chitin is to ______ as glycogen is to starch. A) Cellulose B) Glycoproteins C) Glucose D) Glycosaminoglycans E) Lectins
A) Cellulose
If you mutated a site on an antigen from a threonine to an isoleucine and this disrupted binding, what complementary mutation in the antibody binding pocket would be most likely to restore binding? A) Gln to Leu B) Ile to Lys C) Ser to Asp D) Asn to His E) Trp to Cys
A) Gln to Leu
In humans, ~25% of our energy is spent by____ A) Hydrolysis of ATP to move sodium out of the cell B) Hydrolysis of ATP to move potassium out of the cell C) Sodium influx to drive glucose uptake in the gut D) Sodium efflux to drive glucose uptake in the gut E) Hydrolysis of ATP to move glucose into the cell
A) Hydrolysis of ATP to move sodium out of the cell
In the double reciprocal equation, what is the slope of the line defined as? A) Km/Vmax B) 1/Vmax C) -1/Km D) 1/[S] E) Km/Vmax[S]
A) Km/Vmax
Which two amino acids both destabilize α-helices, and are favored for β-turns? A) Pro and Gly B) Pro and Ala C) Phe and Gly D) Phe and Ala E) Phe and Trp
A) Pro and Gly
Which of the following statements about antibody structure is false? A) The constant domains are located at the ends of the Y-like fork of the antibody, where they form two identical binding sites for antigens. B) The different tertiary structure of the variable domain is responsible for the antigen binding specificity. C) The variable domain has different tertiary structure in both the heavy and light chains. D) Each immunoglobulin consists of two identical heavy chains and two identical light chains. E) All of the above are false
A) The constant domains are located at the ends of the Y-like fork of the antibody, where they form two identical binding sites for antigens.
For amino acids with neutral R groups, at any pH above the pI of the amino acid, the population of amino acids in solution will have: A) a net negative charge. B) a net positive charge. C) no charged groups. D) no net charge. E) positive and negative charges in equal concentration.
A) a net negative charge.
In a β-sheet, the R groups on the amino acid residues: A) alternate between one side and the other side of the sheet. B) are found only the outside of the sheet spiral. C) for the β-turn D) generate the hydrogen bonds that form the sheet. E) are generally hydrophobic
A) alternate between one side and the other side of the sheet.
An allosteric interaction between a ligand and a protein is one in which: A) binding of a molecule to a binding site affects binding properties of another site on the protein. B) multiple molecules of the same ligand can bind to the same binding site. C) binding of a molecule to a binding site affects binding of additional molecules to the same site. D) binding of the ligand to the protein is covalent. E) two different ligands can bind to the same binding site.
A) binding of a molecule to a binding site affects binding properties of another site on the protein.
In hemoglobin, the transition from T state to R state is triggered by: A) oxygen binding. B) heme binding. C) Proton Binding D) Carbamate modification E) subunit dissociation.
A) oxygen binding.
Soap is traditionally made by_______ A) treating fat with basic lye to deprotonate the carboxylic acid group yielding a hydrophobic carbon chain with a negatively charged head group B) treating wax with basic lye to cleave the wax in half to yield a more easily soluble surfactant C) treating fat with acidic lye to protonate the head group, yielding a positively charged head group on a hydrophobic tail D) treating fat with acidic lye to make an otherwise completely polar molecule amphipathic E) treating fat with a detergent to make it amphipathic
A) treating fat with basic lye to deprotonate the carboxylic acid group yielding a hydrophobic carbon chain with a negatively charged head group
In glycolysis, what starts the process of glucose oxidation?
ATP
The main energy-coupling compound in biochemical reactions that allows thermodynamically unfavorable processes to become favorable is ________.
ATP
Which of the following are part of the chemiosmotic coupling model? 1) Protons are pumped out of the mitochondrial matrix into the intermembrane space. 2) The active transport of protons is driven by the free energy derived from electron transport. 3) Increasing the concentration of protons on the other side of the inner membrane creates a charge and a pH imbalance that releases energy upon proton flow back into the matrix. 4) The energy released by the return of protons to the matrix is what drives ATP synthesis.
All of the listed choices are correct.
Which amino acids are responsible for protein absorbing light at 280 nm? A) T, A, and H B) F, W, and Y C) P, G, and K D) those with ionized R-groups E) C-C
B) F, W, and Y
What is the most common net charge on the polypeptide ELVHQRADN at pH 7.5? A) -2 B) -1 C) 0 D) +1 E) +2
B) -1
Calculate the pH of a weak acid that has released 2% of its hydrogens in a 0.1 M solution. A) 3.4 B) 2.7 C) -0.7 D) -1 E) 4.6
B) 2.7
You are working with an amino acid with a pI of 5.66. You would like this amino acid to have a net negative charge, what pH would you make the solution that the amino acid is in? A) 5.66 B) 7.86 C) 1.33 D) 4.00 E) Not enough information
B) 7.86
If one strand of DNA reads, from 5' to 3', GACT, what does the complementary strand read, from 5' to 3'? A) TCAG B) AGTC C) CTGA D) GACT
B) AGTC
Why does wood swell in the direction perpendicular to the grain? A) Cellulose is made up of alpha helices that run perpendicular to the grain and they stretch when hydrated B) Adjacent strands of cellulose that run in the direction of the grain are held together by hydrogen bonds that can be disrupted by water C) The bonds perpendicular to the grain are covalent, while the bonds with the grain are hydrophobic D) The grain is made up of lipids which are hydrophobic, while it is held together by sugars, which are hydrophilic.
B) Adjacent strands of cellulose that run in the direction of the grain are held together by hydrogen bonds that can be disrupted by water
What is the form of glucose is utilized in mammalian cells? A) L-Glucose B) D-Glucose C) E-Glucose D) S-Glucose E) Z-Glucose
B) D-Glucose
The difference between F-actin and G-actin is A) F-actin has a positive end, while G-actin has a negative end B) F-actin has a quaternary structure, while G-actin has only tertiary structure C) G-actin binds to myosin, while F-actin binds to tropomyosin D) F-actin is used for muscle contraction while G-actin is used only in non-muscle cells E) F-actin has both a globular and filamentous domain, while G-actin is only filamentous
B) F-actin has a quaternary structure, while G-actin has only tertiary structure
A thermodynamically unfavorable reaction can become favorable if the mass action ratio (Q) is ________ than the equilibrium mass action ratio (K). A) Greater than B) Less than C) Equal to D) not enough information
B) Less than
N-linked oligosaccharides are: A) Linked to either serine or threonine B) Linked to asparagine C) Linked to either cysteine or tyrosine D) Linked to arginine E) Linked to oline group
B) Linked to asparagine
Which of the following is an accurate description of the Bohr effect? A) Low pH generated by the lungs decreases hemoglobin affinity for oxygen B) Low pH generated by tissues decreases hemoglobin affinity for oxygen C) High pH generated by tissues increases hemoglobin affinity for oxygen D) High pH in the lungs decreases hemoglobin affinity for oxygen E) Increased BPG in muscles decreases hemoglobin affinity for oxygen
B) Low pH generated by tissues decreases hemoglobin affinity for oxygen
What do chaperone proteins do? A) Facilitate B cell tolerance B) Promote protein folding C) Release calcium to stimulate muscle contraction D) Direct proteins to degradation pathways E) Promote the R state of Hemoglobin
B) Promote protein folding
Which of the following refers to the protein structure level that is mostly amino acid side chain independent and is characterized by hydrogen bonding between atoms on the backbone? A) Primary structure B) Secondary structure C) Tertiary structure D) Quaternary structure E) None of the above
B) Secondary structure
Based on the thermodynamic functions of enthalpy and entropy, can an unfavorable reaction that has a positive ΔG at RT be made favorable by increasing the reaction temperature? A) No, an unfavorable reaction cannot be rendered favorable. B) Yes, regardless of the sign of ΔH, if ΔS is positive, a reaction can be rendered favorable by increasing the temperature. C) only if both ΔH and ΔS are negative D) yes, but only if ΔH is positive and ΔS is negative
B) Yes, regardless of the sign of ΔH, if ΔS is positive, a reaction can be rendered favorable by increasing the temperature.
In terms of thermodynamic systems, organisms are: A) a closed system B) an open system C) an isolated system D) a free system E) a down system
B) an open system
A protein domain ____ A) is unique to a specific protein B) is capable of folding on its own C) has no tertiary structure D) is made up of multiple polypeptide chains E) is a recurring short stretch of secondary structure
B) is capable of folding on its own
Protein folding in an aqueous solution is driven by: A) minimization of entropy by the formation of a water solvent shell around the protein. B) maximizing number of hydrogen bonds and hydrophobic interactions. C) maximizing the entropy of the polypeptide backbone while minimizing hydrophobic interactions D) Maximizing the amount of water cages while minimizing the number of hydrogen bonds E) all of the above
B) maximizing number of hydrogen bonds and hydrophobic interactions.
You are interested in two proteins, the 87 kDa Fraggle and and the 37 kDa Snork. The pI of Fraggle is 8.5, and the pI of Snork is 7.6. You would like to bind both of the proteins to an anion exchange column, what pH buffer should you use and which one will come off of the column first as you elute with increasing amounts of salt? A) pH 9.5 buffer, Snork will come off first B) pH 9.5 buffer, Fraggle will come off first C) pH 8.0 buffer, Snork will come off first D) pH 8.0 buffer, Fraggle will come off first E) pH 6.5 buffer, Snork will come off first
B) pH 9.5 buffer, Fraggle will come off first
When getting a perm the α-keratin chains are manipulated in what way? A) oxidation, shape remodeling, then reduction B) reduction, shape remodeling, then oxidation C) shape remodeling, reduction, then oxidation D) shape remodeling, oxidation, then reduction E) Shape remodeling and then chemical reduction
B) reduction, shape remodeling, then oxidation
The sodium/glucose symporter used in the gut epithelium moves sodium __________its gradient, and glucose __________ its gradient. A) down / up B) up / down C) down / down D) up / up
B) up / down
If an enzyme binds an inhibitor more strongly than substrate, what can be said about the free energy of binding compared to that of substrate? A) ΔG is much higher for the inhibitor than the substrate B) ΔG is much lower for the inhibitor than the substrate C) ΔG is roughly equal for the inhibitor and the substrate D) ΔG is not a good measure of favorability of binding for either E) Not enough information
B) ΔG is much lower for the inhibitor than the substrate
Standard chemical conditions would assume water is _____M, but water in biological systems is close to the concentration of pure water, which is _____M. (Remember, water has a molecular weight of 18, and 1 mL of water weighs 1 gram.) A) 55, 1 B) 1, 25 C) 1, 55 D) 1, 1 E) 1, 7
C) 1, 55
The pH of a cell's cytoplasm is 7.4, while tomato juice is pH 4.4. The cytoplasm has: A) 1.68 times the [H+] as the tomato juice. B) 0.59 times lower [H+] than the tomato juice. C) 1000 times lower [H+] than the tomato juice. D) 3000 times lower [H+] than the tomato juice. E) one million times lower [H+] than the tomato juice.
C) 1000 times lower [H+] than the tomato juice.
At what wavelength of light is DNA absorbance of light maximal? A) 180 nm B) 230 nm C) 260 nm D) 600 nm E) 750 nm
C) 260 nm
The following amino acid has pKa's of 2.18, 8.95, and 10.53, for its Carboxyl group, its amine, and the amine in its R group, respectively. The above molecule would be the predominant species in a solution of pH_______. A) 1 B) 2 C) 7 D) 9 E) 11
C) 7
The initial stimulation for muscle contraction is: A) ATP B) troponin T C) Ca2+ D) myosin E) tropomyosin.
C) Ca2+
The three-dimensional structure of macromolecules is formed and maintained primarily through noncovalent interactions. Which one of the following is not considered a noncovalent interaction? A) Hydrophobic interactions B) Hydrogen bonds C) Carbon-carbon bonds D) van der Waals interactions E) Ionic interactions
C) Carbon-carbon bonds
When people don't eat enough fruits and vegetables, they get scurvy. At the molecular level, this is caused by A) Decreased prenylation of lysines in keratin B) Increased phosphorylation of collagen C) Decreased hydroxylation of proline in collagen D) Increased hydroxylation of proline in collagen E) Decreased hydroxylation of Vitamin C
C) Decreased hydroxylation of proline in collagen
What is the major function of triacylglycerol? A) Anchoring proteins to the cellular membrane B) Hormonal signaling C) Energy storage D) Enzyme cofactor E) Pigmentation in organisms
C) Energy storage
Which of the following is correct concerning 2,3-bisphosphoglycerate (BPG)? A) It binds the heme groups of hemoglobin. B) It decreases in concentration with decreasing environmental oxygen C) It decreases the affinity of hemoglobin for oxygen. D) It is a homotropic allosteric modulator. E) It is not normally found associated with the hemoglobin extracted from red blood cells.
C) It decreases the affinity of hemoglobin for oxygen.
Breathing into a bag stops hyperventilation because: A) It slows down how fast you are bringing in Oxygen, thus allowing hemoglobin to shift to the R-state B) It increases the pH in your blood stream to improve the delivery of Oxygen C) It raises the levels of bicarbonate in your blood stream, shifting hemoglobin to the T-state D) The resistance of the bag slows your breathing E) It forces the production of BPG to enhance T-state stability
C) It raises the levels of bicarbonate in your blood stream, shifting hemoglobin to the T-state
Which of the following describes the Vmax of an enzyme? A) It only occurs at one concentration of substrate B) It is occurs when [S] = Km C) It will be reached when all enzyme is bound to substrate D) It is largely dependent upon the affinity of E for S E) It is synonymous with the specificity constant
C) It will be reached when all enzyme is bound to substrate
A biochemist is going to run a reaction at pH 4.8. She has a buffer with a pKa of 4.2, and a buffer with a pKa of 5.3. She makes the decision that the buffer with a pKa of 5.3 would be the better buffer for the reaction than the other. What is her reaction producing? A) Water B) H+ C) OH- D) A buffer with a pKa of 4.8
C) OH-
Which of the following is not true of RNA? A) RNA is less stable than DNA because of the 2' hydroxyl group B) Uracil is used in RNA but not DNA C) RNA is thought to have come after DNA in evolution D) RNA is capable of taking on complex 3-dimensional structures E) RNA can mediate catalysis of biological processes
C) RNA is thought to have come after DNA in evolution
What does knowing that a binding reaction has a Hill coefficient of 0.5 tell you? A) That the binding is positively cooperative B) That the binding is not cooperative C) That the binding is negatively cooperative D) That the binding is allosteric E) That the binding does not happen very fast
C) That the binding is negatively cooperative
If A + B ⇌ C and C + D ⇌ E and all of these species are in a tube: A) Adding excess [A] decreases [E] B) Only one of the reactions can be favorable C) The presence of [D] will drive the loss of [A] and [B] D) Adding addional [C] decreases [E], [A], and [B] E) [E] is needed for the production of [C]
C) The presence of [D] will drive the loss of [A] and [B]
Animals maintain a constant amount of many proteins by continually synthesizing new proteins and degrading old proteins. This is an example of a(n): A) exergonic change. B) free-energy change. C) dynamic steady state. D) equilibrium state. E) waste of energy.
C) dynamic steady state.
Enzymes are potent catalysts in biological systems because they: A) are consumed in the reactions they catalyze. B) are very specific and can prevent the conversion of products back to substrates. C) lower the transition state energy for the reactions they catalyze. D) decrease the equilibrium constants for the reactions they catalyze. E) drive reactions to completion while other catalysts drive reactions to equilibrium.
C) lower the transition state energy for the reactions they catalyze.
Hemoglobin and myoglobin have: A) no obvious structural relationship. B) very different tertiary structures. C) very similar tertiary structures. D) very similar quaternary structures. E) very different tertiary structures, but similar quaternary structures.
C) very similar tertiary structures.
Vitamin C has a pKa of 4.17. What is the ratio of Acid to Conjugate base in solution at pH 3.9? A) 5.70 B) 0.54 C) -0.27 D) 1.86 E) 2.34
D) 1.86
The pH of a solution of 0.01 M Hydrochloric Acid is: A) 0.00 B) 0.01 C) 0.30 D) 2.00 E) 3.00
D) 2.00
When studying RNAse folding, researchers found that A) The primary amino acid sequence contained the necessary information to fold B) Urea must be removed before oxidation for the protein to fold correctly C) Chaperones are required for protein folding D) A and B E) B and C
D) A and B
Which of the following is a FALSE statement about facilitated transport? A) solutes can be transported in opposite directions B) it displays saturation kinetics C) aquaporins have several selective characteristics to transport only water across the membrane D) ATP is always used E) Concentration gradients dictate the thermodynamics of the movement
D) ATP is always used
Stereoisomers that differ at the anomeric carbon are: A) Enantiomers B) Tautomers C) Epimers D) Anomers E) Chiralomers
D) Anomers
In rigor mortis, the Troponin C is bound to _________ and the myosin head groups are bound to ______. A) ATP, Calcium B) ADP, Calcium C) Calcium, ATP D) Calcium, ADP E) Oxygen, ATP
D) Calcium, ADP
The polysaccharide glycogen is used for energy storage in mammalian cells and is cleaved by the glycogen debranching enzyme when sugars are needed for energy production. At which end of the polysaccharide does the enzyme cleave? A) Reducing B) 5' C) Anomeric D) Non-Reducing E) 3'
D) Non-Reducing
Which one of the following is a list of the four most abundant elements in living organisms? A) Carbon, Hydrogen, Oxygen and Sulfur B) Phosphorous, Carbon, Oxygen and Hydrogen C) Phosphorous, Carbon, Hydrogen and Sulfur D) Oxygen, Hydrogen, Carbon and Nitrogen E) Nitrogen, Carbon, Phosphorous, and Oxygen
D) Oxygen, Hydrogen, Carbon and Nitrogen
Which of the following describes the overall three-dimensional folding of complete collagen molecule? A) Primary structure B) Secondary structure C) Tertiary structure D) Quaternary structure E) None of the above
D) Quaternary structure
The immunoglobulin IgA is a glycoprotein that possesses an O-linked oligosaccharide. What amino acid is modified in O-linked glycosylation? A) Cys B) Asn C) Lys D) Ser E) Tyr
D) Ser
In a polypeptide, which bond cannot rotate because of its partial double bond character? A) The Cα-R group bond B) The Namide-Cα bond C) The Ccarbonyl-Cα bond D) The Ccarbonyl-Namide bond E) All bonds are able to rotate freely
D) The Ccarbonyl-Namide bond
The role of an enzyme in an enzyme-catalyzed reaction is to: A) irreversibly bind a transition state intermediate, so that it cannot be converted back to substrate. B) prohibit product from being converted back to substrate.. C) ensure that the product is more stable than the substrate. D) increase the rate at which substrate is converted into product. E) make the free-energy change for the reaction (ΔG°rxn) more favorable.
D) increase the rate at which substrate is converted into product.
Functions of lipids include all of the following except A) energy storage B) membrane structure C) cell signaling D) information transfer E) thermal insulation
D) information transfer
The concept of "induced fit" refers to the fact that: A) enzyme specificity is induced by enzyme-substrate binding. B) enzyme-substrate binding induces an increase in the reaction entropy, thereby catalyzing the reaction. C) enzyme-substrate binding induces a conformational change in the substrate to fit the enzyme D) substrate binding may induce a conformational change in the enzyme, which then brings catalytic groups into proper orientation. E) the enzyme active site fits the substrates current shape and charge without any change
D) substrate binding may induce a conformational change in the enzyme, which then brings catalytic groups into proper orientation.
If the ΔG'° of the reaction A ↔ B is 40 kJ/mol, under standard conditions the reaction: A) is at equilibrium. B) will never reach equilibrium. C) is at a dynamic steady state. D) will proceed spontaneously from B to A. E) will proceed spontaneously from A to B.
D) will proceed spontaneously from B to A.
If the concentration of OH- in a solution is 3.9 x 10-3, what is the pH of the solution? A) 2.41 B) 3.00 C) 3.90 D) 10.10 E) 11.59
E) 11.59
The active site of Snufflease contains an Ile, the sidechain of which interacts with the substrate. If this Ile residue was mutated to another amino acid, which of the following amino acids would you most expect to NOT disrupt the enzyme function? A) Lys B) Gln C) Tyr D) Glu E) Ala
E) Ala
Which of the following can be used as a metabolic control mechanism? a) Regulation of enzyme degradation b) Covalent modification of an enzyme c) Action of hormones D) Enzyme compartmentation E) All of the above
E) All of the above
Which of the following contribute to antibody antigen recognition? A) Hydrogen Bonding B) Shape complementarity C) van der Waals forces D) Ionic interactions E) All of the above
E) All of the above
Which of the following is TRUE of hydrophobic molecules? A) Dissolving in water decreases the entropy of the mixture. B) Water forms a cage-like structure around them. C) They have limited solubility in water. D) They self-associate by releasing some of the surrounding water molecules. E) All of the above
E) All of the above
Which of the following best represents the backbone arrangement of two peptide bonds? A) C—N—Cα—Cα—C—N B) Cα—N—C—C—N—Cα C) Cα—N—Cα—C—Cα—N—Cα—C D) Cα—Cα—C—N—Cα—Cα—C E) Cα—C—N—Cα—C—N
E) Cα—C—N—Cα—C—N
Which of the following is true of glycogen? A) Glycogen contains many reducing ends and few non-reducing ends B) Glycogen is a structural heteropolymer C) Glycogen has a high efficiency because of its large kcat value. D) Glycogen is good for storing energy because its hydrophobic character excludes water and leads to good packing E) Glucose is removed from glycogen at the nonreducing ends.
E) Glucose is removed from glycogen at the nonreducing ends.
Which of the following membranes would be least fluid? A) One containing lipids with polyunsaturated 10 carbon-fatty acids B) One containing lipids with monounsaturated 12 carbon-fatty acids C) One containing lipids with saturated 10 carbon-fatty acids D) One containing lipids with polyunsaturated 12 carbon-fatty acids E) One containing lipids with saturated 12 carbon-fatty acids
E) One containing lipids with saturated 12 carbon-fatty acids
In a mixture of the five proteins listed below, which should elute second in size-exclusion (gel- filtration) chromatography? A) Ran Mr = 25 kDa B) Ubiquitin Mr = 12 kDa C) RCC1 Mr = 53 kDa D) TPR Mr = 240 kDa E) Sst2 Mr = 80 kDa
E) Sst2 Mr = 80 kDa
Which of the following statements about buffers is true? A) A buffer composed of a weak acid of pKa = 5 is stronger at pH 4 than at pH6. B) At pH values lower than the pKa, the conjugate base concentration is higher than that of the acid. C) The strongest buffers are those composed of strong acids and strong bases. D) The pH of a buffered solution remains constant no matter how much acid or base is added to the solution. E) When pH = pKa, the weak acid and salt concentrations in a buffer are equal.
E) When pH = pKa, the weak acid and salt concentrations in a buffer are equal.
In the binding of oxygen to hemoglobin, the relationship between the concentration of oxygen and the fraction of binding sites occupied can best be described as: A) hyperbolic. B) linear with a negative slope. C) linear with a positive slope. D) random. E) sigmoidal.
E) sigmoidal.
T/F? The two carbon atoms that are lost as CO2 in the third and fourth steps of the citric acid cycle are the same as the two carbon atoms of acetyl CoA because of the stereochemistry of the isocitrate dehydrogenase reaction.
False
True or False: Enzyme-catalyzed sequential reactions that make up a metabolic pathway are normally separated in the cell for equal access to reactants.
False
True or False: Substrate-level phosphorylation is a term given to the loss of free energy when ATP is hydrolyzed.
False
How do FAs of different carbon lengths cross into the mitochondrial matrix for oxidation? 1) Small FAs of 10 carbons or fewer can freely diffuse through the membrane. 2) Large FAs are cleaved into two smaller units that are actively transported across the membrane. 3) A membrane-bound transferase catalyzes the conversion of long-chain FAs to FA-carnitine esters, which are transported across the membrane via a specific carrier. 4) The breakdown of large FAs starts outside the matrix, allowing for smaller particles to pass easily through the membrane.
Only statements 1 and 3 are correct.
Which regulatory effects are results of internalized cholesterol? 1) It activates acyl-CoA:cholesterol acyltransferase. 2) It increases endogenous cholesterol synthesis. 3) It downregulates the production of LDL receptors. 4) It inhibits HMG-CoA reductase.
Statements 1, 3, and 4 are direct results of the internalization of cholesterol.
Each round of glycolysis produces ___ ATP and ___ NADH, but spends ___ to do it a) 2/ 2/4 NADH b) 4/2/2 ATP c) 4/2/2 NADH d) 2/2/2 ATP e) 4/4/2 ATP
b) 4/2/2 ATP
Which of the following correctly describes NAD+ and NADP+? a) NAD+ and NADPH are the predominant species in the cell b) NADH and NADPH are the predominant species in the cell c) NADH and NADP+ are the predominant species in the cell d) NAD+ and NADP+ are the predominant species in the cell
a) NAD+ and NADPH are the predominant species in the cell
T/F? All of the enzymes of the citric acid cycle are located in the mitochondrion.
True
True or False: Catabolic processes involve degradation of complex molecules into simpler molecules with the net release of chemical energy.
True
How many electrons must an electron carrier be able to move in a single reaction in order to reduce molecular oxygen at physiological temperatures? a) 1 electron b) 2 electrons c) 3 electrons d) 2 electrons, but they must come with Hydrogen
a) 1 electron
Which of the following is an accurate description of enthalpy? a) It is the heat energy stored in bonds b) It is the amount of disorder present in a system c) It is the complete energy available to do work d) It is the amount of energy required to shift conformation to the transition state e) It is the temperature of a system
a) It is the heat energy stored in bonds
Which of the following is brought into the cell by receptor mediated endocytosis? a) LDL b) HDL c) Chylomicrons d) Cholesterol esters e) Steroid hormones
a) LDL
What molecule is the acetyl group attached to at the beginning of the Citric Acid Cycle? a) Oxoalacetate b) Fumarate c) Citrate d) Succinate e) Malate
a) Oxoalacetate
Which of the following steps in glycolysis is bypassed by gluconeogenesis? a) Phosphoenolpyruvate → Pyruvate + ATP b) Glucose 6-phosphate → Fructose 6-phosphate c) 1,3 Bisphosphoglycerate → 3-Phosphoglycerate + ATP d) 3-Phosphoglycerate → 2-Phosphoglycerate e) Fructose 1,6-bisphosphate → Glyceraldehyde 3-phosphate + Dihydroxyacetone Phosphate
a) Phosphoenolpyruvate → Pyruvate + ATP
[NAD+]/[NADH] a) Ratio is greater than 1. b) Ratio is less than 1. c) Ratio is equal to 1.
a) Ratio is greater than 1.
Which of the following would produce the largest amount of ATP per carbon? a) Saturated fatty acids b) Unsaturated fatty acids c) Carbohydrates d) Amino acids e) The amount of ATP per carbon is identical regardless of chemical environment
a) Saturated fatty acids
The brain does not use fats for energy. In low sugar situations: a) The liver can engage in gluconeogenesis to provide sugar for the brain b) The liver can engage in ketogenesis to provide ketones for the brain c) The pancreas can generate bile salts to break down lipids into sugars for the brain d) The brain will convert its glycogen stores to sugar e) The brain will use Fructose to bypass early steps in glycolysis
a) The liver can engage in gluconeogenesis to provide sugar for the brain or b) The liver can engage in ketogenesis to provide ketones for the brain
Which of the following is not true of Naked Mole Rats? a) They survive in low oxygen by fermenting pyruvate to alcohol b) They survive much longer in low oxygen than mice c) They use fructose 1-phosphate to bypass the early steps of glycolysis d) Citrate buildup from TCA inhibits phosphofructokinase e) They are able to tolerate high CO2 levels
a) They survive in low oxygen by fermenting pyruvate to alcohol
A D-amino acid would interrupt an α helix made of L-amino acids. Another naturally occurring hindrance to the formation of an α helix is the presence of: a) a Pro residue. b) a nonpolar residue near the carboxyl terminus. c) a positively charged Lys residue. d) a negatively charged Arg residue. e) two Ala residues side by side.
a) a Pro residue.
The mechanism for the conversion of α-ketoglutarate to succinyl-CoA resembles the mechanism of which of the following enzymes? a) pyruvate dehydrogenase complex b) aconitase c) phosphoenolpyruvate carboxykinase d) succinate dehydrogenase
a) pyruvate dehydrogenase complex
Which of the following is NOT one of the three stages of respiration? a) the synthesis of pyruvate b) the conversion of pyruvate to acetyl-CoA c) electron transport and oxidative phosphorylation d) the oxidation of acetyl-CoA to two molecules of CO2
a) the synthesis of pyruvate
Propanoic acid has a pKa of 4.874. What is the ratio of Acid to Conjugate base in solution at pH 4.65? a) 0.60 b) 1.67 c) -0.22 d) 9.00 e) 2.34
b) 1.67
How many net molecules of ATP (not total molecules) will be generated by 2 rounds of glycolysis? a) 2 b) 4 c) 6 d) 8 e) 12
b) 4
For the reaction A + B ⇄ C, with the forward rate constant kf = 5.6 x 105 (1/(M s)) and kr the reverse rate constant kr = 0.034 (1/s), what is the rate of loss of C if there is 200 uM C in solution? a) 112 (M/s) b) 6.8 x 10-6 (M/s) c) 1.6 x 10-3 (M/s) d) 607 (M/s) e) 8.9 x10-3 (M/s)
b) 6.8 x 10-6 (M/s)
Which of the following statements about buffers is true? a) A buffer composed of a weak acid of pKa = 7 is stronger at pH 6.5 than at pH 7.5. b) At pH values lower than the pKa, the salt concentration is lower than that of the acid. c) The pH of a buffered solution remains constant no matter how much acid or base is added to the solution. d) When pH = pKa, the net charge is 0 e) The strongest buffers are those composed of strong acids and strong bases.
b) At pH values lower than the pKa, the salt concentration is lower than that of the acid.
To alter the shape of the α-keratin chains—as in hair waving— is a multistep process, one step of which is shown below. What has been done? a) Chemical oxidation b) Chemical reduction c) Hydrolysis d) Shape remodeling e) Protonation
b) Chemical reduction
Fructose 1,6 Bisphosphate is cleaved into two products, which one has to be isomerized before it can continue through glycolysis? a) Glyceraldehyde 3 phosphate b) Dihydroxyacetone phoshpate c) Oxaloacetate d) Carnitine e) Triose Phosphate Isomerase
b) Dihydroxyacetone phoshpate
Which of the following is an accurate explanation of beta oxidation of fatty acids? a) Fatty acids are broken down into 6 carbon sugars to be fed into glycolysis b) Fatty acids are broken down into Acetyl CoA to generate energy through TCA c) Fatty acids are converted to carnitine, which can generate ATP through substrate level phosphorylation d) Fatty acids are broken in half over and over until there are only 2 carbon sugars e) Fatty acids are converted to a beta sheet conformation, and ATP production is directly coupled to their hydrolysis
b) Fatty acids are broken down into Acetyl CoA to generate energy through TCA
The cell produces NAD+ during lactic acid fermentation in the absence of oxygen. Which process uses NAD+ to produce more energy in the absence of oxygen? a) TCA cycle b) Glycolysis c) OxidativePhosphorylation d) B-oxidation e) Gluconeogenesis
b) Glycolysis
During electron transport, energy from _____ is used to pump hydrogen ions into the _____. a) NADH and FADH2 ... mitochondrial matrix b) NADH and FADH2 ... intermembrane space c) NADH ... intermembrane space d) acetyl CoA ... intermembrane space e) NADH ... mitochondrial matrix
b) NADH and FADH2 ... intermembrane space The energy released as electrons, which have been donated by NADH and FADH2, is passed along the electron transport chain and used to pump hydrogen ions into the intermembrane space.
The oxidation of glucose requires 6 moles of O2 and generates 6 moles of CO2. The oxidation of palmitic acid requires 23 moles of O2 and yields 16 moles of CO2. Which of the following statements is true? a) Both processes generate an equal amount of ATP. b) On a molar basis, the combustion of palmitic acid has greater potential to generate more ATP. c) The oxidation of glucose yields more ATP than that of palmitic acid on a molar basis. d) The oxidation of glucose has a lower respiratory quotient than palmitic acid.
b) On a molar basis, the combustion of palmitic acid has greater potential to generate more ATP.
Which one of the following is not among the four most abundant elements in living organisms? a) Carbon b) Phosphorus c) Hydrogen d) Oxygen e) Nitrogen
b) Phosphorus
[NADP+]/[NADPH] a) Ratio is greater than 1. b) Ratio is less than 1. c) Ratio is equal to 1.
b) Ratio is less than 1.
What are the two main products made in the pentose phosphate pathway that will be used in DNA/RNA production and to defend the cell from oxidative stress? a) Ribose 5-phosphate and NADH b) Ribose-5-phosphate and NADPH c) Sedoheptulose 7-phosphate and NADPH d) Glucose 6-phosphate and NADH e) Fructose 6-phosphate and NADPH
b) Ribose-5-phosphate and NADPH
Which of the following is characterized by particularly stable arrangements of amino acid residues in a protein that interact predominantly by hydrogen bonding between atoms on the peptide backbone? a) Primary structure b) Secondary structure c) Tertiary structure d) Quaternary structure e) None of the above
b) Secondary structure
You are studying yet another Unicorn transport protein, Transponyase2, that moves one molecule of 1,2 Rainbowbisphosphate into the cell from outside the cell, in conjunction with moving 2 molecules of glucose in the same direction. Based on this information, what conclusion can you make about the kind of transporter Transponyase2 is? a) Uniporter b) Symporter c) Antiporter d) Active tranporter e) Passive Transporter
b) Symporter
The process by which lactate is regenerated into glucose in the liver is: a) The Kennedy Cycle b) The Cori Cycle c) Lehninger's Loop d) The Urea Cycle e) The Krebs Cycle
b) The Cori Cycle
Since NAD+ and NADP+ are essentially equivalent in their tendency to attract electrons, discuss how the two concentration ratios might be maintained inside cells at greatly differing values. Check all that apply. a) Because NADH-dependent enzymes usually act to hydrogenate (oxidize) substrates, an [NAD+]/[NADH] ratio greater than unity tends to drive reactions in that direction. b) [NADP+]/[NADPH] ratio less than unity provide concentrations that tend to drive these reactions in the direction of substrate reduction. c) [NADP+]/[NADPH] ratio less than unity provide concentrations that tend to drive these reactions in the direction of enzyme oxidation. d) [NADP+]/[NADPH] ratio less than unity provide concentrations that tend to drive these reactions in the direction of substrate oxidation. e) Because NAD+-dependent enzymes usually act to dehydrogenate (oxidize) substrates, an [NAD+]/[NADH] ratio greater than unity tends to drive reactions in that direction. f) Because NAD+-dependent enzymes usually act to hydrogenate (reduce) substrates, an [NAD+]/[NADH] ratio greater than unity tends to drive reactions in that direction.
b) [NADP+]/[NADPH] ratio less than unity provide concentrations that tend to drive these reactions in the direction of substrate reduction. e) Because NAD+-dependent enzymes usually act to dehydrogenate (oxidize) substrates, an [NAD+]/[NADH] ratio greater than unity tends to drive reactions in that direction.
What is another name for Clompex V of the electron transport chain? a) Coenzyme Q b) Ubiquinone c) ATP Synthase d) Pyruvate Dehydrogenase e) Succinate Dehydrogenase
c) ATP Synthase
A futile cycle is: a) two opposing cellular reactions that are independently controlled. b) two reactions or pathways that share substrates and products, and result in no net gain of ATP. c) an endergonic reaction that uses up ATP. d) the reoxidation of NAD+ from NADH. e) the citric acid cycle.
b) two reactions or pathways that share substrates and products, and result in no net gain of ATP.
If the equilibrium ratio of product to reactant for a reaction is 0.25, the forward reaction is ____, and decreasing the amount of product to below the ratio would make it _______. a) favorable, more favorable b) unfavorable, more favorable c) favorable, less favorable d) unfavorable, less favorable
b) unfavorable, more favorable
Which of the following sequences would you expect to be capable of forming a cruciform structure? a. AGCTTGTCGAAC b. AGCTTGCAAGCT c. AGCTTGGTTCGA d. AGCTTGGCAGGT e. AGCTTGAGCTTG
b. AGCTTGCAAGCT
What is the phosphorylation potential of a reaction with a ΔG0' of -25 kJ/mol and a ratio of ([ADP]x[Pi]) to [ATP] of 0.5 at body temperature? a) -21717 J/mol b) 23285 J/mol c) -26717J/mol d) -23282 J/mol
c) -26717J/mol
The polypeptide Leu-Lys-Val-Ser-Gly-Thr-Asp-Ala has what charge at pH 6.5? a) -5 b) -2 c) 0 d) 2 e) 4
c) 0
A protein containing Tryptophan, Tyrosine or Phenylalanine absorbs light at: a) 210nm b) 260nm c) 280nm d) 310nm e) 560nm
c) 280nm
Leucine has a molecular weight of 131, Serine has a molecular weight of 105, what is the molecular weight of the peptide Ser-Leu-Ser ? a) 341 b) 236 c) 305 d) 287 e) 323
c) 305
How much ATP is generated from Acetyl CoA going through one round of the TCA cycle, including the output from oxidative phosphorylation? a) 1 ATP b) 2 ATP c) 9 ATP d) 10 ATP e) 12.5 ATP
c) 9 ATP or d) 10 ATP
Which of the complexes of the ETC pump hydrogens? a) Complexes I and II only b) Complexes I, II, and III c) Complexes I, III, and IV d) Complexes II, III, IV, and V e) Complexes I, II, III, IV, and V
c) Complexes I, III, and IV
Which of the following is not true about oxidation-reduction reactions? a) They usually proceed through heterolytic cleavage. b) During reduction a compound gains electrons. c) Cyotchromes can only move two electrons at a time d) Electrons are commonly transferred using Hydrides e) Every oxidation must be accompanied by a reduction.
c) Cyotchromes can only move two electrons at a time
Substrate level phosphorylation is the term for a) G-protein hydrolysis of GTP b) Production of ATP from ADP by ATP synthase c) Direct transfer of a phosphate to ADP from a molecule with a higher energy phosphate bond d) The first phase of glycolysis e) Any phosphorylation even that occurs inside the matrix of the mitochondria
c) Direct transfer of a phosphate to ADP from a molecule with a higher energy phosphate bond
What is the major function of triacylglycerol? a) Anchoring proteins to the cellular membrane b) Hormonal signaling c) Energy storage d) Enzyme cofactor e) Pigmentation in organisms
c) Energy storage
If one strand of DNA reads, from 5' to 3', TGCATC, what does the complementary strand read, from 5' to 3' a) TGCATC b) CTACGT c) GATGCA d) ACGTAG
c) GATGCA
Which of the following sequences of DNA is likely to have the highest Tm, assuming they are all dissolved in the same buffer? a) TATTAGCCAT b) CCGATTCATA c) GCACTCGAAG d) ACTGTAAGCT e) AATCTTCAAT
c) GCACTCGAAG
Cancer cells undergo mutations in their metabolic processes and rely on only one of the main metabolic pathways to derive ATP in the presence or absence of oxygen. What pathway do they utilize as their main energy source? a) Pentose phosphate pathway b) Oxidative phosphorylation c) Glycolysis d) Gluconeogenesis e) Cori cycle
c) Glycolysis
The following is a representation of a metabolic pathway that involves enzymes w, x, y, z which convert metabolites A, B, C, and D to a product: w x y z A → B → C → D → product If the product inhibits Enzyme X, what will happen to metabolite B? a) It will remain unchanged b) It will decrease in concentration c) It will increase in concentration d) It will inhibit enzyme Y
c) It will increase in concentration
Which of the following is generated in glycolysis and the citric acid cycle? a) NADP+ b) FAD+ c) NAD+ d) Ctyochrome C e) Ubiquinone
c) NAD+
What is the final electron acceptor in the electron transport chain? a) Fe2+ b) Ubiquinone c) O2 d) NAD+ e) NADP+
c) O2
Which of the following is a reason we don't spontaneously burst into flames all the time? a) O2 has a molecular orbital with two electrons in it b) O2 reacts readily with most molecules at body temperature c) O2 with 2 electrons in two different molecular orbitals can only be reduced by special molecules like flavins d) Decoupling of mitochondrial membrane potential promotes reduction to H2O e) Saturated triacylglycerols absorb the excess heat
c) O2 with 2 electrons in two different molecular orbitals can only be reduced by special molecules like flavins
Put the following molecules in order of highest energy phosphate bond to lowest energy: ATP, 1,3-BPG; Creatine Phosphate, PEP, 3-phosphoglycerate a) ATP; 1,3-BPG; Creatine Phosphate; PEP; 3-phosphoglycerate b) 3-phoshpoglycerate; ATP; Creatine Phosphate; 1,3 BPG; PEP c) PEP; 1,3 BPG; Creatine Phosphate; ATP; 3-phosphoglycerate d) PEP; ATP; 1,3-BPG; 3-phosphoglycerate; Creatine Phosphate e) Creatine Phosphate; PEP; 1,3 BPG; 3-phoshphoglycerate; ATP
c) PEP; 1,3 BPG; Creatine Phosphate; ATP; 3-phosphoglycerate
Glycolysis does not require oxygen, but will come to a stop in the absence of oxygen unless: a) Citrate is produced by the Krebs cycle b) Gluconeogenesis replenishes glucose levels c) Pyruvate fermentation is coupled to the oxidation of NADH d) B-oxidation of lipids produces sufficient acetyl CoA e) The mitochondria maintains its proton gradient
c) Pyruvate fermentation is coupled to the oxidation of NADH
Fluoroacetate functions as a poison by what mechanism? a) The compound forms a covalent complex with the aconitase. b) Aconitase converts this compound to a reactive species that covalently modifies the next enzyme in the citric acid cycle. c) This compound is first converted to 2-fluorocitrate, which subsequently inhibits aconitase. d) The compound binds very tightly to but does not form a covalent complex with aconitase.
c) This compound is first converted to 2-fluorocitrate, which subsequently inhibits aconitase.
Which of the following is not a reason for the body to go through the pentose phosphate pathway? a) To generate reducing agent b) To produce nucleotides c) To break down proteins d) To produce pyruvate for the citric acid cycle.
c) To break down proteins
For the chemical reaction A + B ⇌ C at equilibrium, what will happen if you remove C from the system by converting it to D? a) Because it is at equilibrium, nothing will change b) [A] and [B] will increase c) [A] and [B] will decrease d) [D] will decrease e) The ΔG°' for the reaction will decrease
c) [A] and [B] will decrease
The major carrier of chemical energy in all cells is: a) glucose. b) adenosinemonophosphate. c) adenosinetriphosphate. d) phosphoenolpyruvate. e) Creatinephosphate.
c) adenosinetriphosphate.
Which of the four complexes pump protons out of the mitochondrial matrix? a) complexes I, II, and III b) complexes I, II, and IV c) complexes I, III, and IV d) All four complexes pump protons out of the mitochondrial matrix.
c) complexes I, III, and IV
The final electron acceptor of cellular respiration is _____. a) FADH2 b) CO2 c) oxygen d) water e) NADH
c) oxygen
If the ΔG'° of the reaction A → B is 40 kJ/mol, under standard conditions the reaction: a) is at equilibrium. b) will never reach equilibrium. c) will not occur spontaneously. d) will proceed at a rapid rate. e) will proceed spontaneously from A to B.
c) will not occur spontaneously.
If the ΔG'° of the reaction A ↔ B is 40 kJ/mol, under standard conditions the reaction: a) is at equilibrium. b) will never reach equilibrium. c) will not occur spontaneously. d) will proceed at a rapid rate. e) will proceed spontaneously from A to B.
c) will not occur spontaneously.
The pH of a solution of 0.35 M HCl is: a) 0.35 b) -0.46 c) 1.04 d) 0.46 e) -0.35
d) 0.46
For the binding reaction A + B ↔ AB, the rate constants are as follows: the ka is 4.1 x 105 (M-1s-1) and the kd is 0.7 (s-1). What is the dissociation constant, Kd? a) 0.7 (M) b) 4.1 x 105 (M) c) 5.9x105(M) d) 1.7 x 10-6 (M) e) 1.40 x 10-7 (M)
d) 1.7 x 10-6 (M)
Taking one mole of glucose through glycolysis and the citric acid cycle generates: a) 6C02, 8 NADH/H+, 1FADH2 and 1 ATP. b) 6C02, 8 NADH/H+, 2FADH2 and 4 ATP. c) 6C02, 8 NADH/H+, 1FADH2 and 2 ATP. d) 6C02, 10 NADH/H+, 2FADH2 and 4 ATP. e) 6C02, 10 NADH/H+, 2FADH2 and 2 ATP.
d) 6C02, 10 NADH/H+, 2FADH2 and 4 ATP.
One pathway that appears to relate elevated cholesterol levels to atherosclerosis involves the oxidation of LDL. Which of the following are consequences of this process? a) Though the mechanism by which this occurs is not completely understood, this oxidation includes the peroxidation of fatty acids, the hydroxylation of cholesterol, and the oxidation of amino acids. b) Oxidized LDL products induce an immune response that includes recruitment of monocytes and T lymphocytes. c) The presence of scavenger receptors on macrophages allows unlimited cholesterol uptake, leading to its conversion to foam cells. d) All of the listed responses are consequences of this process.
d) All of the listed responses are consequences of this process.
Which of the following enzymes are required for the oxidation of unsaturated FA? a) 2,4-Dienoyl-CoA reductase b) enoyl-CoA isomerase c) acyl-CoA dehydrogenase d) All of the listed responses are correct.
d) All of the listed responses are correct.
Put the following lipoproteins in order from lowest to highest density a) HDL/ VLDL/ LDL/Chylomicron b) VLDL/LDL/HDL/Chylomicron c) Chylomicron/ HDL/ LDL/ VLDL d) Chylomicron / VLDL/ LDL/ HDL e) VLDL/ LDL/ Chylomicron/ HDL
d) Chylomicron / VLDL/ LDL/ HDL
Which of the following is not a product of Pyruvate dehydrogenation? a) NADH b) Acetyl-CoA c) CO2 d) FADH2
d) FADH2
People with a mutant enzyme in their Pentose Phosphate Pathway suffer from toxicity from several sources, including: a) Citrus fruits b) Naked Mole Rat c) Lima Beans d) Fava Beans e) Chicken Liver
d) Fava Beans
Which of the following about glycolysis is false? a) Glycolysis is evolutionarily older than TCA b) Enzymes for glycolysis are conserved from bacteria to humans c) Glycolysis is inhibited by the TCA cycle d) Glycolysis is the primary pathway for the use of lipid break-down products e) Glycolysis occurs in the cytoplasm
d) Glycolysis is the primary pathway for the use of lipid break-down products
In hemoglobin, the transition from T state to R state: a) results in a decrease in affinity of hemoglobin for oxygen b) Is caused by a decrease in pH c) Is stabilized by2,3BPG d) Is a cooperative process e) Is blocked by CO binding
d) Is a cooperative process
Which of the following is the primary electron acceptor in glycolysis and the citric acid cycle? a) FAD+ b) NADP+ c) Ctyochrome C d) NAD+ e) Ubiquinone
d) NAD+
You have initial rate data for an enzyme at a variety of substrate concentrations. What would be the best way to calculate the Vmax? a) The Vmax is just the highest value V0 that you recorded b) Plot V0 vs [S] and estimate the asymptote of the line c) Plot1/[E]vs1/[S]and use the X intercept to calculate the Vmax d) Plot 1/V0 vs 1/[S] and use the Y intercept to calculate the Vmax e) Vmax is equal to V0/Km
d) Plot 1/V0 vs 1/[S] and use the Y intercept to calculate the Vmax
Glycogen is to Starch as Chitin is to _________ a) Glucose b) Glycoproteins c) Starch d) Glycosaminoglycans e) Cellulose
e) Cellulose
In a mixture of the five proteins listed below, which should elute first in size-exclusion (gel- filtration) chromatography? a) cytochrome c Mr = 13,000 b) immunoglobulin G Mr = 145,000 c) ribonuclease A Mr = 13,700 d) RNA polymerase Mr = 450,000 e) serum albumin Mr = 68,500
d) RNA polymerase Mr = 450,000
Which statement about oxidative phosphorylation is NOT true? a) The P/O for NADH is ~2.5. b) The overall energy released by the reduction of O2 to water is more than enough to compensate for the large amount of energy required for ATP synthesis. c) The P/O for succinate is less than that for NADH, at ~ 1.5. d) The mechanisms of phosphorylation and oxidation are directly coupled.
d) The mechanisms of phosphorylation and oxidation are directly coupled.
If the pH of a solution is below the isoelectric pH of a tetrapeptide: a) only the amino and carboxyl termini contribute charge. b) the total net charge is negative. c) the total net charge is zero. d) The total net charge is positive. e) there are four ionic charges.
d) The total net charge is positive.
Which statement about uncouplers is NOT true? a) 2,4-DNP is an example of an uncoupler. b) Their mechanism of action is basically to transport protons back into the matrix, preventing the required buildup of charge on the other side. c) They allow electron transport without ATP synthesis. d) They allow ATP synthesis with no electron transport.
d) They allow ATP synthesis with no electron transport.
The enzymatic activity of G-proteins is a) To exchange GDP for GTP b) Convert ATP to GTP c) Convert GTP to ATP d) To hydrolyze GTP to GDP
d) To hydrolyze GTP to GDP
Which of these is NOT a product of the citric acid cycle? a) ATP b) NADH + H+ c) FADH2 d) acetyl CoA e) CO2
d) acetyl CoA
An allosteric interaction between a ligand and a protein is one in which: a) binding of the ligand to the protein is covalent. b) binding of a molecule to a binding site affects binding of additional molecules to the same site. c)multiple molecules of the same ligand can bind to the same binding site. d) binding of a molecule to a binding site affects binding properties of another site on the protein. e) two different ligands can bind to the same binding site.
d) binding of a molecule to a binding site affects binding properties of another site on the protein.
ATP has a high phosphoryl group transfer potential because: a) it is chemically unstable. b) it has a high rate of spontaneous hydrolysis at physiological pH and temperature. c) it exhibits resonance stabilization prior to hydrolysis. d) cleavage of either of its two phosphoanhydride bonds proceeds with a large negative ΔGo' of hydrolysis. e) it has three phosphate groups.
d) cleavage of either of its two phosphoanhydride bonds proceeds with a large negative ΔGo' of hydrolysis.
The proximate (immediate) source of energy for oxidative phosphorylation is _____. a) ATP synthase b) NADH and FADH2 c) substrate-level phosphorylation d) kinetic energy that is released as hydrogen ions diffuse down their concentration gradient e) ATP
d) kinetic energy that is released as hydrogen ions diffuse down their concentration gradient
Enzymes are potent catalysts because they: a) are consumed in the reactions they catalyze. b) make reactions unidirectional c) drive reactions to completion while other catalysts drive reactions to equilibrium. d) lower the activation energy for the reactions they catalyze. e) decrease the ΔG of the reaction
d) lower the activation energy for the reactions they catalyze.
In the citric acid cycle, ATP molecules are produced by _____. a) photophosphorylation b) cellular respiration c) photosynthesis d) substrate-level phosphorylation e) oxidative phosphorylation
d) substrate-level phosphorylation
If an acid is in a solution with a pH below its pKa, what is the charge on that acid and its protonation state? a) (+), protonated b) (-), protonated c) (+),deprotonated d) (-), deprotonated e) (0), protonated
e) (0), protonated
A true statement about hydrophobic interactions is that they: a) are the driving force in the formation of α-helices b) do not contribute to the structure of water-soluble proteins. c) have bonding energies equivalent to a covalent bond. d) involve the ability of water to denature proteins. e) Are driven by water moving towards a disordered state.
e) Are driven by water moving towards a disordered state.
When exercising, the first store of high energy phosphates with which to replenish depleted ATP come from: a) PEP b) Pyruvate is fermentation c) Nucleoside Diphosphate Kinase replenish ATP from ADP and inorganic Phosphate d) 1,3 Bisphosphoglycerate is made from 2,3 Bisphosphoglycerate in the blood to replenish ATP from ADP e) Creatine Phosphate
e) Creatine Phosphate
How are ATP levels maintained during exercise in muscles? a) Stores of Nucleoside Diphosphate Kinase replenish ATP from ADP and inorganic Phosphate b) Stores of PEP replenish ATP from ADP c) Pyruvate is fermented to Ethanol d) 1,3 Bisphosphoglycerate is made from 2,3 Bisphosphoglycerate in the blood to replenish ATP from ADP e) Creatine Phosphate is used as a source of high energy phosphates to replenish ATP from ADP
e) Creatine Phosphate is used as a source of high energy phosphates to replenish ATP from ADP
Which letter indicates the ΔG of the reaction? a) A b) B c) C d) D e) E Which letter indicates the ΔG of the transition state in a catalyzed reaction? a) A b) B c) C d) D e) E
e) E c) C
What is the first enzyme used in glycolysis? a) Aldolase b) Pyruvate Kinase c) Triose Phosphate Isomerase d) Phosphofructokinase e) Hexokinase
e) Hexokinase
Which of the following is not true of the citric acid cycle? a) It provides metabolites for multiple anabolic processes b) It uses metabolites from multiple catabolic processes c) It occurs in the matrix of the mitochondria d) Oxaloacetate is a part of both the citric acid cycle and gluconeogenesis e) It transfers most of the energy captured to NADPH as high energy electrons
e) It transfers most of the energy captured to NADPH as high energy electrons
Which of the following produces the largest number of reducing equivalents when oxidized? a) NADH b) A hydrogen atom c) NADPH d) Glucose e) Palmitic acid
e) Palmitic acid
Enolase catalyzes the conversion of 2-Phosphoglycerate into what? a) Dihydroxyacetone Phosphate and Glyceraldehyde-3-Phosphate b) 1,3-Bisphosphoglutarate c) Pyruvate d) Glucose6-phosphate e) Phosphoenolpyruvate
e) Phosphoenolpyruvate
Which of these enters the citric acid cycle? a) G3P b) NADH + H+ c) glucose d) pyruvate e) acetyl CoA
e) acetyl CoA
In cellular respiration, most ATP molecules are produced by _____. a) substrate-level phosphorylation b) cellular respiration c) photosynthesis d) photophosphorylation e) oxidative phosphorylation
e) oxidative phosphorylation
Which of the following sequences of DNA is likely to have the lowest Tm, assuming they are all dissolved in the same buffer? a. CCGATTCATA b. TATTAGCCAT c. ACTGTAAGCT d. GCACTCGAAG e. AATCTTCAAT
e. AATCTTCAAT
