BBL - Midterm
All of these compounds are intermediates of glycolysis except A. Glycerol 6-phosphate B. Fructose 1,6-bisphosphate C. Glucose 6-phosphate D. Glyceraldehyde 3-phosphate E. Fructose 6-phosphate
A
Cyanide differs from dinitrophenol (DNP) because cyanide A. is an an inhibitor of the electron transport chain and dinitrophenol is an uncoupler of oxidative phosphorylation B. prevents the formation of a proton gradient and dinitrophenol is an inhibitor of the electron transport chain C. is an inhibitor of the ATP synthase and dinitrophenol is an uncoupler of oxidative phosphorylation D. is highly toxic to human and dinitrophenol is non-toxic
A
Glucose and galactose are A. epimers B. anomers C. enantiomers D. diastereoisomers
A
Is the following statement True of False? A commonly found domain on many receptor molecules such as the LDL receptor (LDLR) is the Beta propeller. A. True B. False
A
Is the following statement True or False? A protein domain is a conserved part of a given protein sequence and tertiary structure that can evolve, function, and exist independently of the rest of the protein chain. A. True B. False
A
Is the following statement True or False? At physiological pH (7.4) the carboxylic acid group will be unprotonated and the amine group will be protonated. A. True B. False
A
Is the following statement True or False? Equilibrium is dependent upon Le Chatelier's Principle. A. True B. False
A
Is the following statement True or False? Post-translational phosphorylation of serine, threonine or tyrosine residues by specific protein kinases is a common amino acid modification. A. True B. False
A
Is this statement about protein function True or False? In biochemical reactions the energy of the exergonic reaction drives the endergonic reaction. A. True B. False
A
Which amino acid would not be found within an alpha-helix? A. Pro B. Arg C. Phe D. Ser
A
Which of the following is a (are) disaccharide(s)? (select all that apply) A. Sucrose B. Glucose C. Fructose D. Lactose
AD
Which of the following is a monosaccharide? (select all that apply) A. Galactose B. Maltose C. Sucrose D. Glyceraldehyde
AD
Acetyl-CoA is produced by the Pyruvate Dehydrogenase Complex by a virtually irreversible reaction. Which of the following coenzymes is NOT involved in this reaction? A. Coenzyme A B. Biotin C. FAD D. TPP
B
All these compounds are glucose polymers except: A. glycogen B. inulin C. cellulose D. starch
B
Among the following, which is a structural polysaccharide? A. glycogen B. pectin C. starch D. inulin
B
Among the following, which is the sweetest sugar? A. sucrose B. fructose C. saccharin D. aspartame
B
At neutral pH, what is true about the ionization of an amino acid? A. The R group is uncharged B. The amino group is protonated but the carboxyl group becomes deprontonated C. Only the carboxylic acid group is deprotonated D. Only the amino group is protonated
B
At which reaction in the citric acid cycle does a substrate-level phosphorylation occurs? A. citrate becoming isocitrate B. succinyl-CoA becoming succinate C. fumarate becoming malate D. alpha-ketoglutarate becoming succinyl CoA
B
Chitin is a polymer of A. N-acetyl D-glucosamine with α-(1→4) linkage B. N-acetyl D-glucosamine with β-(1→4) linkage C. N-acetyl D-galactosamine with α-(1→4) linkage D. N-acetyl D-galactosamine with β-(1→4) linkage
B
Digestion of a protein is a process called? A. Dehydration synthesis B. Hydrolysis C. Esterification D. Proteolysis
B
During a catalyzed reaction, what energy is the lowest? A. delta H of the formation B. delta E of the activation C. delta G of the free energy D. none of the above
B
During glycolysis, the steps between glucose entering the cell and the initial formation of two three-carbon molecules: A. consume two ATP and two NADH molecules B. consume two ATP molecules C. produce two ADP and two NAD molecules D. produce two ATP and two NADH molecules E. consume two NADH molecules
B
Each of these metabolites is a gluconeogenic precursor except one. Which one is the exception? A. lactate B. acetyl CoA C. glycerol D. pyruvate
B
Fructose-2, 6-biphosphate is formed by the action of A. Phosphofructokinase-1 B. Phosphofructokinase-2 C. Fructose biphosphate isomerase D. Fructose-1, 6-biphosphatase E. Fructose-2, 3-biphosphate
B
Glucagon A. stimulates glycogen synthesis and inhibits glycogen degradation B. inhibits glycogen synthesis and stimulates glycogen degradation C. simultaneously inhibits glycogen synthesis and degradation D. simultaneously stimulates glycogen synthesis and degradation
B
Glucose can be made from each of the following substances EXCEPT A. Lactate B. Acetyl CoA C. Glycerol D. Pyruvate E. Fructose
B
How is proline unique among the twenty-one amino acids found in protein? A. Does not have an amine group B. Is a cyclic amino acid C. Does not contain a carboxylic acid group D. Has two R groups
B
How many amino acids are found in a turn of the alpha helix? A. 3 B. 4 C. 5 D. 6
B
How many anomeric carbons are present in a fructose molecule? A. None B. 1 C. 2 D. 4
B
How many moles of ATP are generated by the oxidation of one mole of NADH during oxidative phosphorylation? A. 1.5 B. 2.5 C. 3.5 D. 4.5
B
How many stereoisomers are possible for a ketopentose such as ribulose? A. 2 B. 4 C. 8 D. 16
B
How much ATP is generated per glucose molecule by the 6 NADH and 2 FADH2 produced during the TCA cycle that enter into oxidative phosphorylation? A. 9 B. 18 C. 30 D. 38
B
In a Lineweaver-Burke plot the y intercept corresponds to A. 1/Km B. 1/Vmax C. Km D. Vmax
B
In an alpha helix, hydrogen bonds are formed between peptide NH groups and A. Gly B. Peptide C=O groups C. Pro D. Leu
B
Is the following statement True or False? Carboxyglutamate is generated through the post-transcriptional modification of proteins of the clotting factor cascade. A. True B. False
B
Is the following statement True or False? Cysteine forms the very weak disulfide bonds to hold peptides in place. A. True B. False
B
Is the following statement True or False? The fi and the psi bonds cannot freely rotate around the alpha carbon. A. True B. False
B
Is the following statement True or False? These amino acids; alanine and glycine are called zwitterions and their net charge is +2. A. True B. False
B
Is this statement True or False? In the 'lock & key' model of enzyme function, the active site is of identical shape than the substrate it binds. A. True B. False
B
Is this statement about protein function True or False? Signal transduction receptors are transmembrane proteins that transmit messages from inside the cell to the rest of the neighboring cells. A. True B. False
B
O- linked polysaccharides are attached to which of the following amino acids? A. glycine B. serine C. tryptophan D. aspargine
B
Reaction of glucose with alcohol yields A. sugar acids B. glycoside bonds C. disaccharides D. None of the above
B
Reduction of glucose leads to the formation of A. gluconic acid B. glucitol C. glucoside D. glucosamine
B
Ribozymes are: A. lipids B. catalytic-like RNA molecules C. enzymes D. proteins
B
The amino acids common to all proteins are derived from A. Pentose Phosphate Pathway B. All of the above C. Citric Acid Cycle D. Glycolysis
B
The tricarboxylic acid cycle is initiated by the condensation of which of the following pair of molecules? A. Pyruvate and malate B. Acetyl coenzyme A and oxaloacetate C. Acetyl coenzyme A and oxalosuccinate D. NAD+ and oxaloacetate E. NAD+ and oxalosuccinate
B
What are predominant linkages in glycogen between glucose units? A. Alpha-1,6 B. Alpha-1,4 C. Beta-1,4 D. Beta-1,6
B
What are structural motifs? A. The general structure of a peptide folding B. Super-secondary structure formed from secondary structural regions C. Mixture of secondary structures with specific functions D. All of the above
B
Epinephrine causes an elevation in cAMP levels in muscle cells, which in turn activate A. glycogen synthetase B. ATPase C. glycogen phosphorylase D. glycogen phosphorylase phosphatase E. adenyl cyclase
C
If [S] > Km, then V = ? A. 2 Vmax B. < .5 Vmax C. > .5 Vmax D. Vmax
C
When the linear form of glucose cyclizes, the product is A. an anhydride B. a glycoside C. hemiacetal D. lactose
C
Which of the following sugars is not a reducing sugar? A. Glucose B. Ribose C. Sucrose D. Galactose
C
Approximately how much ATP is stored in the human body at any given time and approximately how much ATP does the human body need to produce daily? A. 200-300 mg - 80 g B. 200-300 g - 80 g C. 200-300 mg - 80 kg D. 200-300 g - 80 kg
D
Between meals, one main source of blood glucose is A. liver insulin B. liver sucrose C. liver amylose D. liver glycogen
D
The function of beta barrels in eukaryotic cells is A. Receptors for nuclear proteins B. Enzymes in the mitochondria C. Transmembrane proteins in the nucleus D. Unique transport structure of the mitochondria
D
Which of the following energetic processes drives the formation of a proton gradient across the inner mitochondrial membrane during oxidative phosphorylation? A. ATP hydrolysis B. ATP synthesis C. ADP transport D. Electron transfer
D
Which of the following is unique to α-keto acid dehydrogenase complexes? A. GDP B. FAD C. H2O D. NAD+ E. Lipoic acid
E
Fill in the blank: The transformation of a monosaccharide into its __________ occurs easily and does not require the assistance of a catalyst.
anomer
All of the following statements about NAD+ are true EXCEPT A. NAD+ has more chemical energy than NADH B. In the absence of NAD+, glycolysis cannot function C. NAD+ is reduced by the action of dehydrogenases D. NAD+ can receive electrons for use in oxidative phosphorylation E. NAD+ is reduced to NADH during both glycolysis and the Krebs cycle
A
Energy for ATP synthesis is derived from the electron transport system by which of the following processes? A. Oxidative phosphorylation B. Aldolization C. Oxidative deamination D. Reductive synthesis E. Transamination
A
Excess blood glucose levels would stimulate which of the following processes in the liver? A. glycogen synthesis B. glycogen degradation C. lipolysis D. none of the above
A
How are the amino acid side chains arranged around the alpha helix? A. Perpendicular and outward form the helix B. Perpendicular and either inward or outward to the axis peptide C. Inward to the axis of the axis of the peptide D. None of the above
A
In covalent catalysis A. A transient covalent bond is formed between the acyl intermediate and the enzyme B. The acyl group binds to the cofactor C. The acyl group is the first group leaving the active site D. All of the above
A
In glycoproteins, the carbohydrate moiety is always attached through the following amino acid residues A. asparagine, serine, or threonine B. aspartate or glutamate C. glycine, alanine, or aspartate D. tryptophan, aspartate, or cysteine
A
In the formation of covalent bonds, the electronic repulsion that results when atoms approach each other results in: A. activation energy B. free entropy C. free enthalpy D. equilibrium constant
A
Is the following statement True or False? In acid-base catalysis, both acid and base lower the kinetic barrier and speed up the attainment of chemical equilibrium. A. True B. False
A
Is the following statement True or False? The alpha carbon is not the number 1 carbon in an amino acid. A. True B. False
A
Is the following statement True or False? The hydrogen bonds of parallel beta sheet regions are weaker than the hydrogen bonds between anti-parallel beta sheet regions. A. True B. False
A
Is the following statement True or False? Two bio-polymers may share the same motif but yet lack secondary structure similarity. Existence of a sequence motif does not necessarily imply a distinctive structure. A. True B. False
A
Is this statement True or False? The enzyme makes the formation of the transition state energetically possible. The formation of product comes about by the enzyme overcoming the activation energy barrier. A. True B. False
A
Is this statement about protein function True or False? Bacterial proteins follow the same rules as eukaryotic cells to fold proteins into tertiary and quaternary structures. A. True B. False
A
Is this statement about protein function True or False? The energy diagram shows that the presence of a catalyst in a reaction causes a decrease in the energy needed to form the product. A. True B. False
A
Maltose is composed of A. glucose and glucose B. glucose and galactose C. glucose and fructose D. glucose and sucrose
A
Pyruvate oxidation to Acetyl-CoA is a virtually irreversible reaction that involves: A. 3 enzymes and 5 coenzymes B. 3 enzymes and 3 coenzymes C. 5 enzymes and 5 coenzymes D. 5 enzymes and 3 coenzymes
A
Salivary amylase hydrolyses which of the following bonds? A. α-(1→4) glycosidic linkages B. α-(1→6) glycosidic linkages C. β-(1→4) glycosidic linkages D. β-(1→6) glycosidic linkages
A
Starting with glyceraldehyde 3-phosphate and synthesizing one molecule of pyruvate, the net yield of ATP and NADH would be which of the following? A. 2 ATP, 1 NADH B. 1 ATP, 4 NADH C. 2 ATP, 2 NADH D. 1 ATP, 2 NADH E. 1 ATP, 1 NADH
A
Substrate-level phosphorylation differs from oxidative phosphorylation in that: A. oxidative phosphorylation involves the transfer of electrons B. substrate-level phosphorylation involves the transfer of electrons C. substrate-level phosphorylation only occurs in the cytosol D. GTP is always involved in substrate-level phosphorylation E. oxidative phosphorylation only occurs in the cytosol
A
The binding of the LDL to the beta propeller of the LDL receptor is dependent on A. pH B. ion content of the cell C. temperature D. All of the above
A
The carbohydrate in highest concentration in resting muscle is A. Glycogen B. Lactose C. Inositol D. Sucrose E. Glucose
A
The function of the cytochromes in the electron transport chain is A. to transport electrons via reversible oxidation-reduction of iron B. to prevent oxidation of iron C. to enable iron to bind oxygen D. to catalyze the formation of NADH
A
What is the behavior of delta G in a catalyzed or uncatalyzed reaction? A. it remains the same B. it decreases C. it is lower in catalyzed reactions compared to uncatalyzed reactions D. it increases
A
What is the spatial orientation of amino acids in a peptide? A. Amino acids are trans of each other B. Each amino acid is cis of its neighbor C. Can be either cis or trans D. None of the above
A
What term best describes a metabolic pathway that use simple precursors and energy to produce complex molecules? A. Anabolism B. Catabolism C. Metabolism D. All of the above
A
When do beta turns occur? A. when proline or glycine are in position 2 and 3 respectively B. when tyrosine and serine are in position 2 and 3 respectively C. when serine and threonine are in position 2 and 3 respectively D. when glycine and tyrosine are in position 2 and 3 respectively
A
Which of the following interconversions is a site of reciprocal regulation between glycolysis and gluconeogenesis? A. pyruvate and phosphoenolpyruvate B. glucose 6-phosphate and fructose 6-phosphate C. 2-phosphoglycerate and 3-phosphoglycerate D. glyceraldehyde 3-phosphate and dihydroxyacetone
A
Which of the following intermediary metabolites of the TCA cycle is formed, in part, by the removal of a CO2 molecule? A. α-ketoglutarate B. Oxaloacetate C. Citrate D. Malate E. Lactate
A
Which of the following is not a common symptom of galactosemia? A. Obesity B. Enlarged liver C. Delayed mental development D. Cataracts
A
Which of the following liver enzymes, absent from other tissues, gives the liver an advantage over other cells in taking up glucose after a meal? A. Glucokinase B. Aldolase C. Hexokinase D. Glucose 6-phosphatase E. Enolase
A
Which of the following occurs in both the TCA cycle and the glyoxylate cycle? A. The conversion of malate to oxaloacetate B. The introduction of two molecules of acetyl-CoA per cycle C. Substrate level phosphorylation D. The conversion of alpha-ketoglutarate to succinyl-CoA
A
Which of the following polysaccharides cannot be digested by mammalian salivary, gastric, or pancreatic enzymes? A. cellulose B. amylopectin C. amylose D. glycogen
A
Which sugar produced by the pentose phosphate pathway is used in the synthesis of RNA and DNA? A. ribose 5-phosphate B. ribulose 5-phosphate C. fructose 6-phosphate D. xylulose 5-phosphate
A
Why does the glycolytic pathway continue in the direction of glucose catabolism? A. There are three irreversible reactions along the glycolytic pathway that prevent the reformation of free glucose B. High levels of ATP keep the pathway going in a forward direction C. All of the enzymes of glycolysis function in one direction D. All of the above
A
A 15-year-old Type-1 diabetic faints after injecting insulin. He is administered glucagon and rapidly recovers consciousness. Glucagon induces activity of: A. Glycogen synthase B. Glycogen phosphorylase C. Glucokinase D. Hexokinase
B
If the net flux of a fructose 1,6-bisphosphate being formed from fructose 6-phosphate is zero, what is happening on the molecular level? A. The formation of fructose 1,6-bisphosphate is inhibited due to allosteric control. B. The amount of fructose 1,6-bisphosphate being formed from fructose 6-phosphate is equal to the amount of fructose 6-phosphate being formed from fructose 1,6-bisphosphate. C. The formation of fructose 6-phosphate is inhibited due to allosteric control. D. The amount of fructose 1,6-bisphosphate being formed from fructose 6-phosphate is greater than the amount of fructose 6-phosphate being formed from fructose 1,6-bisphosphate.
B
In the serine protease the catalytic triad is composed of A. Threonine, serine, valine B. Serine, histidine, aspartate C. Histidine, serine, valine D. Serine, glycine and valine
B
Is the following statement True or False? A salt bridge is a combination of hydrogen bonding and electrostatic interaction between a positively charged R group and a negatively charged R group. A. True B. False
B
Is the following statement True or False? All amino acids contain at least two weakly acidic groups. A. True B. False
B
Rossman's Fold, commonly found in dehydrogenase enzymes, binds A. FAD B. NAD(H) C. Glucose D. Metal cofacors
B
Succinate dehydrogenase differs from all other enzymes in the TCA cycle in that it is the only enzyme that displays which of the following characteristics? A. It contains bound FAD B. It is embedded in the inner mitochondrial membrane C. It contains Fe-S centers D. It is regulated by a kinase E. It is inhibited by NADH
B
The R groups of the beta sheet regions are found A. Between the adjacent regions B. Trans in the direction of the region C. Cis and trans to the axis of the region D. Outward from the direction of the axis of the strand
B
The absence of which enzyme in the galactose metabolic pathway is known to be the cause of galactosemia? A. Galactokinase B. Galactose 1-phosphate uridyl transferase C. UDP galactose 4-epimerase D. Hexokinase
B
The chemical energy generated by mitochondrial electron transport results from which of the following? A. Excess H+ in the matrix B. An H+ gradient across the inner membrane C. The formation of thioesters in the matrix D. A conformational change in the inner membrane E. None of the above
B
The glucose residue linkages of glycogen are A. beta(1-4) and alpha(1-6) B. alpha(1-4) and alpha(1-6) C. beta(1-4) and beta(1-6) D. alpha(1-4) and beta(1-6)
B
The hydrogen bonds of an alpha helix are located between the first amino acid (n) and amino acid (n+__) A. 3 B. 4 C. 5 D. 6
B
The principal organ in which gluconeogenesis occurs is the A. kidney B. liver C. brain D. intestine
B
The quantity Vmax on the Lineweaver-Burk plot represents A. the point where the line crosses the X axis B. the point where the line crosses the Y axis C. the slope of the line D. none of the above
B
The reaction that takes place in the hexokinase active site is considered to be an example of induced fit. Why? A. Because hexokinase will bind glucose only B. Because hexokinase binds several 6 carbon sugars C. Because hexokinase only binds straight chains D. None of the above
B
The reactions of the TCA cycle oxidizing succinate to oxaloacetate A. require coenzyme A B. require both NAD+ and FAD C. include an isomerization reaction D. produce one high-energy phosphate bond
B
The structure of collagen is A. Large globular protein B. Long linear protein made up of three intertwined alpha helical peptides bound together C. Has an equal mix of alpha helix an beta sheet secondary structures D. A hetrodimeric protein
B
The tertiary structure of a protein A. is also known as its subunit number B. is believed to be the structure of lowest free energy C. contains the maximum number of hydrogen bonds D. contains the maximum number of disulphide bonds
B
What is meant by calling the peptide bond a resonance structure? A. The bond between the atoms vibrates B. The bond between the atoms form a partial double bond C. The bond is cis D. All of the above
B
What is meant by native configuration? A. The secondary structure of protein B. The tertiary structure of protein in its folded state with lowest entropy C. Linear polymer of amino acids D. The sequence amino acids coded by the gene
B
What is not a characteristic of allosteric enzymes? A. allosteric enzymes may be inhibited by a feedback mechanism B. allosteric enzymes are released as inactive precursors C. allosteric inhibitors bind to regulatory subunits D. allosteric enzymes are usually multisubunit
B
What is the molecular formula for glucose? A. CH3OH B. C6H12O6 C. C12H22O11 D. C6H12O5
B
What is the principal role of the pentose phosphate pathway? A. Production of energy by pentose phosphate synthesis B. Production of NADPH for use in reductive biosynthetic reactions C. Production of glycogen during fasting D. Alternative source of glycogen when glycolysis is not possible
B
Which of the following characterizes an asymmetric carbon? A. It has four identical groups attached to it B. It has four different groups attached to it C. It has at least one carboxyl and one amino group attached to it D. It has two heavy groups on one side and two light groups on the other
B
Which of the following enzymes is involved with regulating the glycolytic pathway? A. Enolase B. Pyruvate kinase C. Triose phosphate isomerase D. Phosphoglycerate mutase
B
Which of the following generates free glucose during the enzymatic breakdown of glycogen in skeletal muscle? A. phosphorylase B. debranching enzyme C. amylase D. glucose-6-phosphatase E. None of the above
B
Which of the following is true regarding enzymes? A. are needed in large amounts B. catalyze exergonic and endergonic reactions C. increase the energy of activation of the reaction D. their effectiveness as catalysts is independent of temperature
B
Which of the following molecules are typically oxidized in catabolic reactions? A. Enzyme and coenzymes B. Carbohydrates and fats C. Vitamins and coenzymes D. Nucleotides and flavins
B
Which of the following statements is false? A. Sucrose is a disaccharide B. Sucrose is a reducing sugar C. Sucrose can be digested by invertase D. Fructose is a component of sucrose
B
Which one of the following reactions is unique to gluconeogenesis? A. Lactate → Pyruvate B. Oxaloacetate → Phosphoenol pyruvate C. Glucose-6-phosphate → Glucose D. Phosphoenol pyruvate → Pyruvate E. None of the above
B
Which pair of amino acids contains polar side chains? A. val and ile B. arg and glu C. ser and trp D. leu and lys
B
Why is the TCA cycle the central pathway of metabolism of the cell? A. It occurs in the center of the cell B. Its intermediates are commonly used by other metabolic reactions C. All other metabolic pathways depend upon it D. None of the above
B
Why is the initial rate of a reaction an important measurement? A. because it determines how quickly the reaction will occur B. because we measure the forward reaction with no back reaction C. both of the above D. none of the above
B
A 28-year-old professional cyclist has been training for a long race. His coach strongly suggests the intake of carbohydrates after the workout to ensure a muscle glycogen storage that can endure the 14-day race. The activity of muscle glycogen synthase in resting muscles is increased by the action of which of the following? A. Epinephrine B. Glucagon C. Insulin D. Phosphorylation
C
A disaccharide produced through hydrolysis of starch is A. sucrose B. lactose C. maltose D. theralose
C
An example of a naturally occurring protein secondary structure is A. alpha-random coil B. collagen double helix C. alpha helix D. contour-pleated sheet
C
At neutral pH, which statement is correct about amino acid ionization? A. The anime group is ionized B. The carboxylic acid group is ionized C. Both are ionized D. Neither are ionized
C
Carbohydrates are stored in the body principally as A. glucose B. sucrose C. glycogen D. glycosaminoglycans
C
Coupled respiration requires each of the following EXCEPT A. ADP B. Oxygen C. Carbon dioxide D. Electron donor E. None of the above
C
Desmosine cross linkages are formed by which amino acid? A. Leucine B. Alanine C. Lysine D. Valine
C
During an exergonic reaction A. the energy of the product is always greater than the substrate B. the energy of the product is always the same as the substrate C. the energy of the product is always less than the substrate D. it depends on the reaction
C
Enzymes concerned with the citric acid cycle are found in the A. nucleus B. ribosomes C. mitochondria D. nonparticulate cytoplasm E. none of the above
C
For an amino acid to be zwitterionic A. Every group is fully ionized B. The carboxylic acid and amine group are ionized, the R group has charge C. The carboxylic acid and amine group are ionized, the R group has no charge D. None of the above
C
Glucose enters muscle cells mostly by: A. co-transport with amino acids B. active transport C. facilitated diffusion using a specific glucose transporter D. simple diffusion E. co-transport with sodium
C
Glycogen phosphorylase cleaves which of the following molecules from glycogen? A. Glucose B. Glucose-6-phosphate C. Glucose-1-phosphate D. Maltose
C
High concentrations NADH, acetyl-CoA, and ATP inhibit the pyruvate dehydrogenase complex (PDH) by activating which of the following enzymes? A. dihydrolipoyl dehydrogenase B. dihydrolipoamide acetyltransferase C. pyruvate dehydrogenase kinase D. pyruvate dehydrogenase phosphatase
C
How are the beta sheet regions of a protein stabilized? A. Inter-strand hydrogen bonds B. Salt bridges between regions C. Hydrogen bonds between adjacent chains D. Disulfide bonds between regions
C
How many amino acids are in found in a beta turn? A. 2 B. 3 C. 4 D. 5
C
How many stereoisomers are possible for an aldopentose such as ribose? A. 2 B. 4 C. 8 D. 16
C
Hydrolysis of sucrose by the enzyme sucrase yields A. glucose only B. glucose and maltose C. glucose and fructose D. glucose and galactose
C
In metallo-catalysis, the metal is found A. Bound to the substrate B. Transient in the active site C. Covalently bound to the protein D. Bound to the co-enzyme
C
In the 'induced fit' model of the enzyme's active site A. The substrate binds to the complementary shaped active site B. The protein forms the active site when substrate binds C. When substrate binds to the active site, a conformational shift occurs D. None of the above
C
In the conversion of fructose to glyceraldehyde and dihydroxyacetone phosphate, what intermediate is formed? A. Fructose 6-phosphate B. Fructose 1,6-bisphosphate C. Fructose 1-phosphate D. Fructose 2,6-bisphosphate
C
Lactate formed in muscles can be utilized through A. Rapoport-Luebeling cycle B. Glucose-alanine cycle C. Cori's cycle D. Citric acid cycle E. TCA cycle
C
Nitrogen enters the biomass through anabolic pathways that produce A. Alanine B. Aspartate / asparagine C. Glutamate / glutamine D. All of the above
C
Select the option that accurately completes the following statements. The role of NAD+ is to __________ electrons in metabolic pathways while the role of NADH is to _________ electrons. In general, nicotinamide adenine dinucleotide is referred to as an electron _________. A. donate.....accept....generator B. donate....accept....carrier C. accept...donate....carrier D. accept...donate....generator
C
Selenocysteine is formed A. by replacing the sulfide group with a seleno group B. by adding a seleno group to pyruvate after it is aminated by glutamate C. by adding a seleno group to the seryl residue on the specific seryl-tRNA D. none of the above
C
Sodium fluoride inhibits glycolysis by affecting A. hexokinase B. phosphorylase C. enolase D. amylase E. phosphatase
C
The NADH generated by glycolysis is transported into mitochondria by A. diffusion B. selective permeability C. metabolic shuttles D. all of the above
C
The NADH that is produced by glycolysis under anaerobic conditions is regenerated to NAD+ by the conversion of A. lactate to pyruvate B. phosphoenolpyruvate to pyruvate C. pyruvate to lactate D. glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate E. None of the above
C
The absorption of glucose in the digestive tract A. Is impaired in cases of diabetes mellitus B. Is stimulated by the hormone glucagon C. Occurs in the small intestine D. Occurs more rapidly than the absorption of any other sugar E. Depends on the levels of insulin in the bloodstream
C
The committed step in glycolysis is A. glucose + ATP leads to glucose 6-phosphate B. glucose 6-phosphate leads to fructose 6-phosphate C. fructose 6-phosphate + ATP leads to fructose 1,6-bisphosphate D. fructose 1,6-bisphosphate leads to dihydroxyacetonephosphate + glyceraldehyde 3-phosphate E. glucose 6-phosphate leads to glucose 1-phosphate
C
The first step in the gluconeogenic pathway (starting with pyruvate) results in the formation of A. malate B. phosphoenolpyruvate C. oxaloacetate D. aspartate
C
The hydrolysis of lactose yields A. glucose only B. glucose and fructose C. glucose and galactose D. galactose and fructose
C
The mechanism of catalysis by lysozyme involves: A. an active serine B. destabilization of the product by the enzyme C. protonation of the substrate by the enzyme D. cleavage of a small peptide
C
The pI region on the titration curves for all amino acids are important because A. it is the point were both groups are ionized B. it represents the pH level with greatest buffering capacity C. All of the above D. None of the above
C
The principal purpose of ribose-5-phosphate in cells is to A. be activated and polymerized into glycogen B. be activated and made into a glycosaminoglycan C. be an essential part of every nucleotide D. be a metabolic intermediate in the oxidative phase of the pentose phosphate pathway E. serve as a metabolic intermediate in the dark reactions in photosynthesis
C
The reason why there is a small dipole charge along a peptide is because A. The charge of the R groups B. The charge on the alpha carbon C. The charge of the amine nitrogen and the carbonyl group D. None of the above
C
The site on the enzyme globular protein were the substrate binds and is converted to product is called A. Binding cleft B. Allosteric site C. Active site D. None of the above
C
The stoichiometry of NADPH to ribose 5-P in the pentose phosphate pathway is A. 1:2 B. 1:1 C. 2:1 D. 4:1 E. 3:1
C
What bond holds amino acids in a linear hetropolymer? A. Glyocsidic bond B. Ester linkage C. Peptide bond D. Phosphodiester bond
C
What is a cofactor? A. An organic molecule B. A metal ion like Mg2+ C. All of the above D. None of the above
C
What is the function of a coenzyme in enzyme reactions? A. It works as part of the enzyme B. It aids the binding of the substrate to the enzyme C. It is the repository for the function group being substituted into to the substrate D. All of the above
C
What is the relationship between velocity and KM? A. Vmax on the Y axis equals KM on the X axis B. Vmax on the X axis equals KM on the Y axis C. Vmax/2 is Km on the X axis D. None of the above
C
What makes each of the 21 amino acids found in protein unique? A. The carboxylic acid and the amine group B. The presence of the alpha carbon C. The chemistry of the unique R groups found in each D. All of the above
C
When NADPH is in high demand by the cell, which two gluconeogenic intermediates produced by the pentose phosphate pathway can be used to resynthesize glucose 6-phosphate? A. fructose 6-phosphate and fructose 1,6-bisphosphate B. dihydroxyacetone phosphate and fructose 6-phosphate C. glyceraldehyde 3-phosphate and fructose 6-phosphate D. glyceraldehyde 3-phosphate and fructose 1,6-bisphosphate
C
When hydrogen ions are pumped out of the mitochondrial matrix, across the inner mitochondrial membrane, and into the intermembrane space, the result is: A. a damage to the mitochondrion B. the reduction of NAD+ to NADH C. the creation of a proton gradient D. the uncoupling of oxidative phosphorylation
C
Where in the cell does oxidative phosphorylation occur? A. Cytosol B. Outer mitochondrial membrane C. Inner mitochondrial membrane D. Mitochondrial matrix
C
Which amino acids are post-transcriptionally phosphorylated? A. Tyrosine, phenylalanine, alanine B. Glutamate, histidine, tryptophan C. Serine, threonine, tyrosine D. Alanine, arginine, cysteine
C
Which of the following enzymes is essentially absent from normal mammalian muscle? A. Glucokinase B. Phosphorylase C. Glucose-6-phosphatase D. Glucose-6-phosphate isomerase E. Glucose-6-phosphate dehydrogenase
C
Which of the following is a dominant feature of the outer membrane of the cell wall of gram negative bacteria? A. amylose B. cellulose C. lipopolysaccharides D. lipoproteins
C
Which of the following is not a reaction at which the TCA cycle is regulated by cellular levels of ATP? A. pyruvate to acetyl-CoA B. isocitrate to alpha-ketoglutarate C. malate to oxaloacetate D. alpha-ketoglutarate to succinyl-CoA
C
Which of the following is not considered a polysaccharide? A. starch B. glycogen C. maltose D. cellulose
C
Which of the following is responsible for increasing blood glucose levels? A. Insulin B. Glycolysis C. Glucagon D. Catabolism
C
Which of the following metabolic conversions is considered to be the major control point of glycolysis? A. Glucose to glucose-6-phosphate B. 2-phosphoglyerate to phosphoenolpyruvate C. Fructose-6-phosphate to fructose-1,6-bisphosphate D. pyruvate to lactate
C
Which of the following molecules is a carbohydrate? A. C3H7O2N B. C13H26O2 C. C6H12O6 D. C6H12O12
C
Which of the following statement is NOT true of the TCA cycle ? A. Acetyl-CoA enters the TCA cycle and joins a four-carbon molecule to form citrate B. FAD is an electron acceptor in the cycle C. Decarboxylation occurs at one location in the cycle D. NADH is formed at three locations in the cycle
C
Which of the following statements regarding glycogen metabolism is INCORRECT? A. glycogen consists of alpha-1,4 and alpha-1,6-glycosidic bonds B. a debranching enzyme is needed for the complete breakdown of glycogen C. glycogen is synthesized and degraded by the same pathway D. cyclic AMP is the main second messenger involved in the regulation of glycogen metabolism
C
Which statement is(are) correct? A. S'adenosylmethionine is formed from methionine and ATP by S'adnosylmethoinine transferase B. S'adenosylmethionine is the donor of methyl groups to macromolecules C. All of the above D. None of the above
C
Which structure is stabilized by hydrogen bonds? A. Alpha helix B. Beta sheet C. Both alpha helix and beta sheet D. None of the above
C
Which type of bond found in protein is strongest? A. hydrogen B. hydrophobic C. covalent D. electrostatic
C
Why is selenocysteine an uncommon amino acid only found in protein? A. It contains both a seleno group and a sulfide group B. It is the only non-polar amino acid C. Selenium is substituted for sulfide to form selenocysteine on the unique sec-t-RNA D. All of the above
C
A Hill plot A. is used to show inhibition B. is another way of determining Vmax and KM C. is used to determine the kcat D. shows co-operativity in binding of substrate
D
A polysaccharide formed by beta 1—>4 glycoside linkage is: A. starch B. dextrin C. glycogen D. cellulose
D
All of the amino acids found in protein are derived from which metabolic pathway? A. Glycolysis B. Pentose Phosphate pathway C. Tricarboxylic acid cycle D. All of the above
D
Alpha-chymotrypsin and trypsin are serine proteases which have the same A. primary structures B. specificities C. binding sites D. catalytic groups
D
Alpha-ketoglutarate is a precursor for which of the following classes of biomolecules? A. Sterols B. Fatty acids C. Porphyrins D. Amino acids
D
At equilibrium in solution, d-glucose consists of a mixture of its anomers. Which statement most accurately describes the solution? A. The solution consists of approximately equal amounts of the alpha- and beta-anomers B. The straight-chain form is present in high concentration C. The alpha-anomer is more stable and is slightly preferred over the b-anomer D. The beta-anomer predominates over the alpha-anomer by a ratio of approximately 2:1
D
Chemical compounds that have the same structural formula but differ in configuration around one carbon atom are called A. optical isomers B. stereoisomers C. anomers D. epimers
D
Choose the correct statement: A. Functions of protein catalysts include increasing interaction specificity and inhibiting the formation of side products B. Enzymes have the capacity for regulation allowing control of biological pathways C. Enzymes increase the rate of a reaction without being used up in the reaction D. All of the above
D
During which phase of cellular respiration does the majority of ATP production occur? A. during glycolysis B. during operation of the TCA cycle C. during operation of the electron transport chain D. during oxidative phosphorylation
D
Gluconeogenesis is decreased by A. Glucagon B. Epinephrine C. Glucocorticoids D. Insulin E. Glycogen
D
Hydrolysis of sucrose by the enzyme sucrase yields A. fructose and maltose B. glucose and maltose C. glucose and galactose D. glucose and fructose E. glucose only
D
In which of the following organelles would the conversion of pyruvate to acetyl-CoA and the TCA cycle be found? A. nucleus B. lysosomes C. golgi complex D. mitochondria E. endoplasmic reticulum
D
Muscle glycogen does not yield blood glucose directly but liver glycogen does because A. muscle cells are impermeable to glucose B. muscle glycogen differs in structure from liver glycogen C. muscle does not contain phosphoglucomutase D. glucose-6-phosphatase is not present in muscle E. hexokinase is not present in liver
D
One of the principal functions of the pentose phosphate pathway is to A. metabolize glucose completely to carbon dioxide B. produce fructose-6-phosphate C. maintain the ratio of NAD+/NADH at a very high level in the cytosol D. maintain the ratio of NADPH/NADP+ at a very high level in the cytosol E. metabolize galactose
D
Oxygen in myoglobin is bound by what metal? A. Copper B. Zinc C. Vanadium D. Iron
D
Products of the metabolism of glucose-6-phosphate include or are incorporated into: A. glycogen B. acetyl-CoA C. DNA and RNA D. All the above
D
Protein concentration can be measured by UV light absorbance at 280 μm because of the presence of which amino acids? A. Polar amino acids B. Non-polar amino acids C. Acid or basic amino acids D. Aromatic amino acids
D
Rotenone is a poison commonly added to insecticides. Insects exposed to rotenone will die because A. high levels of fermentation products will build-up B. water will not be produced and dehydration will occur C. anaerobic respiration cannot occur D. of insufficient ATP production by oxidative phosphorylation
D
Succinate dehydrogenase differs from all other enzymes in the TCA cycle in that it is the only enzyme that displays which of the following characteristics? A. It is inhibited by NADH B. It contains Fe-S centers C. It is regulated by a kinase D. It is embedded in the inner mitochondrial membrane E. It contains bound FAD
D
The biochemical property of lectins that is the basis for most of their biological effects is their ability to bind to A. amphipathic molecules B. hydrophobic molecules C. specific lipids D. specific oligosaccharides
D
The most rapid method to re-synthesize ATP during exercise is through: A. glycogenolysis B. tricarboxylic acid cycle (Krebs' cycle) C. glycolysis D. phosphocreatine breakdown E. gluconeogenesis
D
The numbering of the carbons in an amino acid begins? A. At the amine group B. The R group C. The alpha carbon D. The carboxylic acid
D
The peptide bond is formed between which two groups of the amino acids? A. The amine group of the first amino acid to the carbonyl of the second amino acid in a polypeptide B. Between the R group of the first and the R group of the second amino acid in a polypeptide C. The alpha carbons of each amino acid in a polypeptide D. The carboxylic acid group of the first and the amine of the second amino acid in a polypeptide
D
The typical cyclical structure of glucose is α and β D- A. Chondroitin B. Glucoside C. Glucosamine D. Glucopyranose
D
To possess optical activity, a chemical compound must be A. a hexose B. aromatic C. symmetric D. asymmetric
D
What is a common way in which enzymatic pathways are regulated to optimize the amount of product formed and substrate consumed? A. Substrate control B. Metabolic control C. Enzyme control D. Allosteric control
D
What is the most common rate-limiting substrate in oxidative phosphorylation? A. succinate B. acetate C. glucose D. ADP
D
What mechanism is used to transport oxaloacetate out of the mitochondria and into the cytosol during the initial steps of the gluconeogenic pathway? A. the sodium potassium shuttle B. the glucose alanine shuttle C. the glycerol phosphate shuttle D. the malate aspartate shuttle
D
Which is not a component of hemoglobin? A. pyrrole rings B. polypeptide chain C. ferrous ion D. cytochrome c
D
Which of the following characterizes an asymmetric carbon? A. A carbon atom that has two heavy groups on one side and two light groups on the other B. A carbon atom with four identical groups attached to it C. A carbon atom with partial negative charge D. A carbon atom with four different groups attached to it E. A carbon with at least one carboxyl and one amino group attached to it
D
Which of the following compounds does NOT contain a high-energy bond? A. ATP B. Phosphoenolypyruvate C. UDP-glucose D. Glucose 6-phosphate E. Acetyl CoA
D
Which of the following is glucogenic amino acid? A. Leucine B. Isoleucine C. Phenylalanine D. Alanine E. Tyrosine
D
Which of the following is not involved in the metabolism of galactose? A. Galactokinase B. UDP-glucose C. Glucose 1-phosphate D. Triose kinase
D
Which of the following is responsible for decreasing blood glucose levels? A. Glycolysis B. Insulin C. GLUT2 D. All of the above
D
Which of the following pair of amino acids is expected to be found in beta turns? A. Lys and Arg B. Arg and Leu C. Val and Asp D. Gly and Pro
D
Which of the following pair of amino acids is expected to be found on the interior of a globular protein? A. Lys and Arg B. Arg and Leu C. Val and Asp D. Trp and Phe
D
Which of the following pairs is interconverted in the process of mutarotation? A. D-glucose and D-fructose B. D-glucose and D-galactose C. D-glucose and L-glucose D. α-D-glucose and β-D-glucose
D
Which of the following pairs of amino acid residue changes would most likely lead to a change in protein function? A. Asp-glu B. Asn-gln C. Ser-thr D. Phe-arg
D
Which of the following statements about actin and myosin proteins is correct? A. They work together to cause skeletal muscle contraction B. Actin moves along the myosin protein C. The action of these two proteins requires ATP D. All of the above
D
Which term best describes the manner in which glycolysis and gluconeogenesis regulate one another? A. Catabolic regulation B. Metabolic regulation C. Circular regulation D. Reciprocal regulation
D
Aerobic resynthesis of ATP occurs A. in the cytosol B. in the sarcoplasmic reticulum C. only in Type I muscle fibres D. in the mitochondria in a process called glycogenolysis E. in the mitochondria in a process called oxidative phosphorylation
E
Anaerobic metabolism refers to the generation of ATP A. without the use of glycogen B. by the conversion of pyruvate to lactate C. in the absence of available oxygen D. without the involvement of ADP E. without the use of oxygen
E
At the end of the TCA cycle, most of the energy remaining from the original glucose is stored in A. FADH2 B. CO2 C. pyruvate D. ATP E. NADH
E
How many moles of ATP are generated by the complete aerobic oxidation of 1 mole of glucose to 6 moles of CO2? A. 18 to 22 B. 60 to 64 C. 10 to 12 D. 2 to 4 E. 30 to 32
E
In eukaryotes, the enzymes that catalyze the reactions of glycolysis are located in: A. the cell nucleus B. the endoplasmic reticulum C. the mitochondria D. the lysosomes E. the cytosol
E
The TCA cycle is an oxidative pathway requiring oxygen for operation. The enzyme which consumes oxygen during the operation of the cycle is A. Isocitrate dehydrogenase B. Alpha-ketoglutarate dehydrogenase C. Aconitase D. Cytochrome c oxidase E. None of the above
E
The arrangement of sugars into D- and L- configurations is based upon their resemblance to D- and L- A. glucose B. fructose C. glycine D. glucosamine E. glyceraldehyde
E
The enzymes of the pentose phosphate pathway are found in the A. Cellular membrane B. Mitochondria C. Endoplasmic reticulum D. Nucleus E. Cytosol
E
When glycogen is degraded, glucose 1 phosphate is formed. Glucose 1 phosphate can then be isomerized to glucose 6 phosphate. Starting with glucose 1 phosphate and ending with two molecules of pyruvate, what is the net yield of glycolysis in terms of ATP and NADH formed? A. 2 ATP, 3 NADH B. 2 ATP, 1 NADH C. 2 ATP, 2 NADH D. 1 ATP, 3 NADH E. 3 ATP, 2 NADH
E
