Old Exams

Question 1

Please choose the true statement:

a. Sickle cell anemia is a recessive autosomal mutation that results in forming fibers of myoglobin that deform the red blood cell
b. In aqueous solution, most proteins are surrounded by a hydration layer of water molecules that hydrogen bond with hydrophilic amino acids on the protein surface
c. Adult hemoglobin becomes the predominant hemoglobin in the body just prior to birth
d. Fetal hemoglobin has a higher affinity for 2,3 bisphosphoglycerate (2,3BPG) than does adult

Answer 1

b. In aqueous solution, most proteins are surrounded by a hydration layer of water molecules that hydrogen bond with hydrophilic amino acids on the protein surface

Question 2

You are studying a protein that has an aspartate residue in the active site. Which of the following would be least likely to disrupt function of this protein?

a. Replacing this amino acid with glycine
b. Replacing this amino acid with glutamate
c. Replacing this amino acid with serine
d. Replacing this amino acid with proline

Answer 2

b. Replacing this amino acid with gluatmate

Question 3

Please choose the false statement

a. Denaturants disrupt protein structure and cause a loss of normal function
b. Chaperone numbers increase during heat stress and are known as heat shock proteins
c. Change in pH can result in denaturing conditions and loss of enzyme function
d. Beta-mercaptoethanol works by ionizing amino acid side chains

Answer 3

d. Beta-mercaptoethanol works by ionizing amino acid side chains

Question 4

What is the pH of solution of acetic acid, when [acetate] = 1 mM, [acetic acid] = 10 µM; the pKa = 5.6

a. 2.6
b. 4.6
c. 6.4
d. 7.6
e. None of the above

Answer 4

d. 7.6

Question 5

Please select the true statement:

a. Ionic bonds are non-directional
b. The fatty acid tails of membrane lipids primarily associate through hydrogen bonding
c. In solving for the energy present in an ionic bond, positive values of E are attractive, whereas negative values for E are repulsive
d. Both a and c are true

Answer 5

a. Ionic bonds are non-directional

Question 6

Which buffer is optimal for an enzymatic reaction if the enzyme optimal pH = 3.8

a. Acid A, with the following pKas: pKa1 = 2.2, pKa2 = 4.8, pKa3 = 3.8
b. Acid C with the following pKas: pKa1 = 6.1, pka2 = 7.8
c. Acid B with the following pKas: pKa1 = 4.1, pKa2 = 9.8
d. Acid D with the following pKas: pKa1 = 2.0, pKa2 = 5.0, pKa3 = 8.1

Answer 6

c. Acid B with the following pKas: pKa1 = 4.1, pKa2 = 9.8

Question 7

Please select the true statement:

a. RNA is translated by RNA polymerase, which uses RNA as the template
b. DNA is used as a template during the translation of proteins
c. The polymerization of nucleic acids is driven forward by mass action through the loss of PPi
d. Replication uses deoxyribonucleotides only during the synthetic process
e. All the above are true

Answer 7

c. The polymerization of nucleic acids is driven forward by mass action through the loss of PPi

Question 8

Which of the following is false?

a. Carbon dioxide produced in metabolically active cells is a substrate for carbonic anhydrase
b. The heme ring is an asymmetrical prosthetic group, as the portion that is buried in the global chain and the portion that contacts the aqueous solution are not the same
c. Carbonic anhydrase catalyzes the irreversible production of carbonic acid from CO2 and H2O
d. Hemoglobin in the tense state has a lower affinity for oxygen than hemoglobin in the relaxed state

Answer 8

c. Carbonic anhydrase catalyzes the irreversible production of carbonic acid from CO2 and H2O

Question 9

What is the pH of a liter of 0.1 M NaOH?

a. 13
b. 12
c. Approximately 7
d. 2
e. 1

Answer 9

a. 13

Question 10

Please select the true statement:

a. Fetal hemoglobin is a tetramer of two alpha-globing chains and two beta-globing chains
b. The secondary structure of myoglobin is primarily beta sheet loops and coils
c. Human myoglobin and the human hemoglobin are paralogs
d. Myoglobin functions as a tetramer and shows allosteric binding kinetics

Answer 10

c. Human myoglobin and the human hemoglobin are paralogs

Question 11

Please choose the true statement:

a. At a pH greater than the pKa of an acid, the acid is present at higher concentration than its conjugate base
b. Buffers are weak acids that buffer most effectively at the pKa of the acid, but generally have buffering capacity within 1 pH unit above and 1 pH unit below the acid’s pKa
c. The bicarbonate buffer system is the primary cellular buffering system
d. Although they have ionizable groups, free amino acids cannot function as buffers

Answer 11

b. Buffers are weak acids that buffer most effectively at the pKa of the acid, but generally have buffering capacity within 1 pH unit above and 1 pH unit below the acid’s pKa

Question 12

The normal 3-D structure of a single protein chain is called its tertiary structure.

a. True
b. False

Answer 12

a. True

Question 13

Which of the following is true:

a. In peptide synthesis, the peptide bond forms between the alpha amino group of the amino acid already in the chain, and the alpha carboxy group of the incoming amino acid being added
b. In peptide synthesis, the peptide bond forms between the alpha-carboxy group of the amino acid already in the chain, and the alpha-amino group of the incoming amino acid being being added
c. In peptide synthesis, the peptide bond forms between the alpha-carbon of the amino acid already in the chain, and the alpha-amino group of the incoming amino acid being added
d. In peptide synthesis, the peptide bond forms between the alpha-amino group of the amino acid already in the chain, and the alpha-carbon of the incoming amino acid being added

Answer 13

b. In peptide synthesis, the peptide bond forms between the alpha-carboxy group of the amino acid already in the chain, and the alpha-amino group of the incoming amino acid being being added

Question 14

In the lipid bilayer, lipids are held together by covalent bonds to form the lipid membrane.

a. True
b. Flase

Answer 14

b. False

Question 15

Please select the true statement:

a. The proximal histidine of hemoglobin acts to limit access to the central iron ion, and prevent superoxide release
b. When oxygen leaves hemoglobin oxygen-binding site as superoxide, the resultant oxidation state of that iron in the heme molecule is 3+
c. The primary function of myoglobin is to carry oxygen in the blood
d. The iron in methemoglobin is at the 2+ oxidation state

Answer 15

b. When oxygen leaves hemoglobin oxygen-binding site as superoxide, the resultant oxidation state of that iron in the heme molecule is 3+

Question 16

In aqueous solution, polar amin acids are most commonly on the outside of a protein, while non-polar amino acids are generally buried inside the proton, away from the aqueous solution.

a. True
b. False

Answer 16

a. True

Question 17

Please select the false answer:

a. The four elements at the highest mole percent in humans are H, C, N, O
b. Chiral amino acids that comprise proteins are in the D-configuration with respect to the chirality of the alpha-carbon substituents
c. A covalent bond between two carbon atoms has a higher bond energy than the van der Waals interactions between two carbon atoms
d. Hydrogen bonds are linear interactions

Answer 17

b. Chiral amino acids that comprise proteins are in the D-configuration with respect to the chirality of the alpha-carbon substituents

Question 18

Please select the true statement:

a. Prolines tend to kink the peptide backbone, and are commonly found in the middle of an alpha helix
b. Free aniline has a positive charge of zero in aqueous solution at physiologic pH
c. Glycine is one of the most commonly substituted amino acids in proteins because it is so small
d. Disulfide bonds form between two cysteine residues under reducing conditions

Answer 18

b. Free aniline has a positive charge of zero in aqueous solution at physiologic pH

Question 19

Select the false statement:

a. Alpha helices are held in position by hydrogen bonds parallel to the axis of the helix
b. Hydrogen bonds that stabilize alpha helices form between main chain atoms 3-4 amino acids apart
c. Peptide bonds show partial double bond characteristics
d. Beta-strands are held together in a beta-sheet by hydrogen bonds that form between R groups
e. Amino acid R’ groups project outward from the alpha helices

Answer 19

d. Beta-strands are held together in a beta-sheet by hydrogen bonds that form between R groups

Question 20

Alpha helices are helical structures that are hallow at the center of the helix

a. True
b. Flase

Answer 20

b. Flase

Question 21

The amino acid sequence of a yeast protein is 80% identical to its human homolog, but the DNA sequences of the gene that encode these two proteins are only 65% identical. How can this be?

a. Changes in amino acid sequence are tolerated more easily than changes in DNA sequence
b. Changes in amino acid sequence rarely result in loss of function, while changes in DNA coding sequence generally does result in a change in the function of the coded protein
c. Mutations leading to differences in DNA sequence might not lead to differences in amino acid sequences because the genetic code is degenerate
d. RNA is often mutated, while DNA is more stable and this accounts for the difference
e. All the above are true
f. Only a, c, and d are true

Answer 21

c. Mutations leading to differences in DNA sequence might not lead to differences in amino acid sequences because the genetic code is degenerate

Question 22

The approximate energy (E) of an electrostatic interaction formed between two ions, both with a charge of -1, which are 1.0 Angstroms apart in a solution with a dielectric constant of 2 will have a positive value.

a. True
b. False

Answer 22

a. True

Question 23

Which amino acids have side chains that can form an ionic bond (salt bridge) with one another at physiologic pH?

a. Ala and Arg
b. Asp and Arg
c. Lys and Arg
d. Cys and Asp
e. Aso and Leu

Answer 23

b. Asp and Arg

Question 24

Of the 20 amino acids found in proteins, those classified as acidic have a full formal negative charge at physiologic pH.

a. True
b. False

Answer 24

a. True

Question 25

Please choose the true statement:

a. Catabolic pathways are divergent, oxidizing and release energy
b. Lysine is a zwitterion at physiologic pH
c. Alanine has a positive charge at pH 12
d. The side chains of Cys and Met can make disulfide bonds with one another

Answer 25

a. Catabolic pathways are divergent, oxidizing and release energy

Question 26

The nitrogenous bases in DNA are cytosine, guanine, adenine, and uracil.

a. True
b. False

Answer 26

b. False

Question 27

Oxygen has a lower affinity for hemoglobin, and tends to be released, under which of the following conditions:

a. High pH and High CO2
b. Low pH and Low CO2
c. High pH and Low CO2
d. Low pH and High CO2

Answer 27

d. Low pH and High CO2

Question 28

Please choose the true statement:

a. One codon can correspond to more than one amino acid
b. All amino acids are encoded by two or more codons
c. Each of the 64 codons encodes an amino acid
d. Only c and d are true
e. None of the above statements are true

Answer 28

e. None of the above statements are true

Question 29

Please choose the true statement:

a. The covalent bonds that link nucleotides together in DNA or RNA are phosphoanhydride bonds
b. 6 M urea is a denaturant used to to disrupt covalent peptide bonds in proteins
c. The 4 classes of macromolecules are carbohydrates, proteins, lipids, and nucleotides
d. Amyloid fibers are readily accessible to cellular protease digestion, as their structure is abnormal

Answer 29

c. The 4 classes of macromolecules are carbohydrates, proteins, lipids, and nucleotides

Question 30

Please select the false statement:

a. Alpha helices in most proteins are right-handed
b. The total entropy of a system must increase for a reaction to be favorable
c. A beta-turn is a secondary structural element representing a sharp turn that changes the direction of a peptide strand
d. Motifs are super-secondary structures formed by secondary structural elements that are positioned in a specific order, one right after another, to form a distinctly typical pattern that is the hallmark of that motif

Answer 30

b. The total entropy of a system must increase for a reaction to be favorable

Question 31

Please select the false statement:

a. Glycogen is a storage form of glucose polymer that is found in animal tissues
b. Hydrogen bonding is greater in glycogen and starch than it is in cellulose and chitin
c. The bonds linking sugars together to form carbohydrate polymers are called glycosdisic bonds
d. Cellulose and starch are both glucose polymers
e. Glycogen is more highly branched than starch

Answer 31

b. Hydrogen bonding is greater in glycogen and starch than it is in cellulose and chitin

Question 32

Please select the true statement:

a. Interactions between amino acid side chains determine whether any two given amino acid residues will form a peptide bond
b. Valine and methionine are hydrophobic, branched chain amino acids
c. Tryptophan, tyrosin and phenylalanine are aromatic amino acids
d. There are no true answers here.

Answer 32

c. Tryptophan, tyrosin and phenylalanine are aromatic amino acids

Question 33

Glycine, alanine, and leucine are hydrophobic amino acid.

a. True
b. False

Answer 33

b. False

Question 34

Please choose the trues statement:

a. Cysteine is a conservative substitution for methionine
b. Tryptophan is a conservative substitution for alanine
c. Leucine is a conservative substitution for valine
d. All of the above are true
e. Only a and c are true

Answer 34

c. Leucine is a conservative substitution for valine

Question 35

Transcription factors in archaea are more similar to transcription factors in humans than to transcription factors in E. coli

a. True
b. False

Answer 35

a. True

Question 36

What is the ΔG when ΔS = 100 J/molK, ΔH = 10 kJ/mol, and T = 298 K?

a. 7.02 kJ/mol
b. -7.02 kJ/mol
c. 12.98 kJ/mol
d. -12.98 kJ/mol
e. 19.8 kJ/mol
f. -19.8 kJ/mol
g. 39.8 kJ/mol
h. -39.8 kJ/mol

Answer 36

f. -19.8 kJ/mol

Question 37

Please select the true statement:

a. Our bodies represent closed systems
b. The energy described by: Esystem + Esurroundings is always a number greater than zero
c. The pI of a protein is the pH at which each amino acid in the protein has no charge
d. Some proteins need the assistance of chaperones to fold correctly
e. Only c and d are true

Answer 37

d. Some proteins need the assistance of chaperones to fold correctly

Question 38

The second law of thermodynamics says that: the entropy of the system never decreases.

a. True
b. False

Answer 38

b. False

Question 39

Please select the true statement regarding heme synthesis:

a. The first reaction of heme synthesis is a condensation reaction between the TCA cycle intermediate succinyl CoA and the amino acid glycine.
b. The first reaction in heme synthesis forms delta-aminolevulinate.
c. Propionate side chains are hydrophobic and help to anchor the heme ring into the hydrophobic pocket of the globin peptide chain.
d. All the above are true
e. Only a and b are true.

Answer 39

e. Only a and b are true.

Question 40

For a reaction in the presence of a competitive inhibitor, Vmax > Vmaxapp.

a. True
b. False

Answer 40

b. False

Question 41

Forming lactic acid from pyruvate is an oxidation reaction, with NAD+ as the electron acceptor, and lactate plus NADH and H+ as the products.

a. True
b. False

Answer 41

b. False

Question 42

Two identical reactions one of which has an enzyme added, are allowed to reach equilibrium. Will there be a significant difference in these two reactions?

a. The ratio of products to reactants will be more in the non-catalyzed reaction.
b. The ratio of products to reactants will be less in the non-catalyzed reaction.
c. The ratio of products to reactants will be the same in the both reactions

Answer 42

c. The ratio of products to reactants will be the same in the both reactions

Question 43

When glucose levels are low, the activity of the glycolytic pathway is increased.

a. True
b. False

Answer 43

b. False

Question 44

Please select the true statement:

a. Pyruvate carboxylase is a cytoplasmic enzyme.
b. Pyruvate carboxylase requires coenzyme A to activate pyruvate.
c. Pyruvate carboxylase requires a biotin cofactor to transfer electrons to pyruvate to form lactate.
d. None of these statements is true.

Answer 44

d. None of these statements is true.

Question 45

How many molecules of delta-aminolevulinate does it take to form a heme ring?

a. 2
b. 4
c. 8
d. 16

Answer 45

c. 8

Question 46

Glucagon response in the liver results in which of the following?

a. Inhibition of gluconeogenesis
b. Inhibition of phosphofructokinase 2 (PFK2)
c. Activation of hexokinase. (HK)
d. Activation of phosphofructokinase 1. (PFK1)

Answer 46

b. Inhibition of phosphofructokinase 2 (PFK2)

Question 47

Which of the metabolites below has a lower phosphoryl transfer potential than ATP?

a. Creatine phosphate
b. 1,3-bisphosphoglycerate (1,3-BPG)
c. Glycerol 3-phosphate
d. Phosphoenolpyruvate. (PEP)

Answer 47

c. Glycerol 3-phosphate

Question 48

Please choose the true statement:

a. The pace of glycolysis is set by the enzyme hexokinase.
b. During gluconeogenesis, non-carbohydrate molecules like amino acids can be used as a carbon source for the synthesis of glucose.
c. Muscle cells release glucose in response to glucagon in order to supply the brain and red blood cells with this free glucose.
d. None of the above is true.

Answer 48

b. During gluconeogenesis, non-carbohydrate molecules like amino acids can be used as a carbon source for the synthesis of glucose.

Question 49

Where does glycolysis occur?

a. cytoplasm
b. mitochondrion
c. nucleus
d. lysosome

Answer 49

a. cytoplasm

Question 50

The vitamin, folic acid is important for which of the following?

a. Electron transfer
b. Nitrogen transfer
c. Aldehyde transfer
d. Single carbon transfer
e. None of the above.

Answer 50

d. Single carbon transfer

Question 51

Fructose catabolism during glycolysis in the liver bypasses phosphofructokinase I.

a. True
b. False

Answer 51

a. True

Question 52

In glycolysis, which two enzymes generate ATP:

a. Hexokinase and Pyruvate kinase
b. Phosphoglycerate kinase and pyruvate kinase (PK)
c. PFK1 and Pyruvate kinase
d. Phosphoglycerate kinase and phosphoenolpyruvate carboxykinase

Answer 52

b. Phosphoglycerate kinase and pyruvate kinase (PK)

Question 53

Please choose the false statement: (PDC = pyruvate dehydrogenase complex)

a. The pyruvate dehydrogenase complex catalyzes the oxidative decarboxylation of pyruvate to yield a 2-carbon group and CO2.
b. The cofactor lipoamide is used by the pyruvate dehydrogenase complex to transfer an acetyl group to Co Enzyme A.
c. The pyruvate dehydrogenase complex uses FADH2 to oxidize dihydrolipoamide to re-form the functional lipoamide and FAD.
d. To form lipoamide, lipoic acid is covalently linked to the ε-amino group of a lysine in the PDC

Answer 53

c. The pyruvate dehydrogenase complex uses FADH2 to oxidize dihydrolipoamide to re-form the functional lipoamide and FAD.

Question 54

Please choose the correct pair consisting of a vitamin paired with its deficiency:

a. Vitamin D – Scurvy
b. Folic Acid – Neural tube defects
c. Vitamin C – Rickets
d. Thiamine – Osteomalacia

Answer 54

b. Folic Acid – Neural tube defects

Question 55

In the Cori cycle, lactate produced in the muscles and red blood cells travels in the blood stream to the liver, where the lactate is used to make glucose in the process of gluconeogenesis.

a. True
b. False

Answer 55

a. True

Question 56

Please choose the true statement:

a. Gluconeogenesis occurs primarily in the brain (~90%), and to a lesser degree in the red blood cells (~10% ).
b. Gluconeogenesis generally occurs when the cells need energy in the form of ATP.
c. The primary fuel of the brain and the sole fuel of erythrocytes is glucose.
d. Oxaloacetate enters the mitochondrion to be used to form pyruvate during gluconeogenesis.

Answer 56

c. The primary fuel of the brain and the sole fuel of erythrocytes is glucose.

Question 57

When blood sugar is low, which of the following is true:

a. Pyruvate kinase is activated.
b. Fructose bisphosphatase 2 is activated
c. Phosphofructokinase 2 is activated.
d. The concentrations of fructose 2,6-bisphosphate (FBP2) are increased.

Answer 57

b. Fructose bisphosphatase 2 is activated

Question 58

KM is the concentration of substrate at which the rate of enzyme activity is at half maximal.

a. True
b. False

Answer 58

a. True

Question 59

Please solve for V0 when [S] = 0.002 mM, [E] = 3 µM, Vmax = 6 µM second-1, and KM = 4 µM

a. 2/3 µM second-1
b. 6/10 µM second-1
c. 1 µM second-1
d. 2 µM second-1
e. The correct value is not given.

Answer 59

d. 2 µM second-1

Question 60

Please select the true statement:

a. Fluoride is a competitive inhibitor of pyruvate kinase.
b. Arsenate can substitute for phosphate in the substrate phosphorylation of fructose 6-phosphate.
c. Oxaloacetate must be reduced to malate because malate cannot enter or leave the mitochondrion.
d. None of the above is true.

Answer 60

d. None of the above is true.

Question 61

Please select the true statement:

a. Carbonic anhydrase requires a Zn2+ metal cofactor to destabilize and acidify a bound water molecule.
b. To allow carbonic anhydrase to work rapidly, protons must be brought into the active site by histidine.
c. Carbonic anhydrase predominantly runs in reverse in red blood cells circulating in lung capillaries to form bicarbonate from CO2 and water.
d. None of these statements is true

Answer 61

a. Carbonic anhydrase requires a Zn2+ metal cofactor to destabilize and acidify a bound water molecule.

Question 62

Please select the true statement regarding heme catabolism:

a. The major product of uroporphyrinogen III synthase is a symmetric ring formed by cyclizing the linear tetrapyrrole.
b. Heme synthesis is primarily regulated through positive feedback by the product, heme.
c. Ferrochelatase is a mitochondrial enzyme that inserts Fe3+ into the tetrapyrrole.
d. The final processes of heme catabolism are carried out by gut bacteria

Answer 62

d. The final processes of heme catabolism are carried out by gut bacteria

Question 63

Please select the false statement regarding heme catabolism: more than one answer is false.

a. The spleen is the major site of removal and degradation of aging red blood cells.
b. Serum albumin is an amphipathic protein that carries hydrophobic molecules in the blood.
c. Biliverdin reductase catalyzes the formation of the product biliverdin from the starting reactant bilirubin.
d. The major products of heme catabolism are eliminated in the feces and urine and help to color these waste products.
e. Conjugated biliverdin is carried in bile to the small intestine.

Answer 63

c. Biliverdin reductase catalyzes the formation of the product biliverdin from the starting reactant bilirubin.
e. Conjugated biliverdin is carried in bile to the small intestine.

Question 64

Please select the true statement:

a. Increase in serum bilirubin diglucuronide above normal can be a sign of such things as neonatal jaundice, resolution of a large hematoma or hemolytic anemia.
b. Concentrations of porphobilinogen are lower than normal in a person suffering from acute intermittent porphyria.
c. Congenital erythropoietic porphyria is a genetic disorder that can result in uroporphyrinogen I deposits in the teeth and under the skin.
d. All the above are true.

Answer 64

c. Congenital erythropoietic porphyria is a genetic disorder that can result in uroporphyrinogen I deposits in the teeth and under the skin.

Question 65

Please select the true statement:

a. The primary function of an enzyme is to increase the rate of a given reaction.
b. Enzymes are consumed in the reactions that they catalyze which is why enzyme deficiencies are so prevalent in disease processes.
c. Many enzymes work through destabilizing the transition state in a given reaction.
d. In the reaction catalyzed by carbonic anhydrase, dimolecular oxygen is cleaved to form superoxide, O2- a potent nucleophile.

Answer 65

a. The primary function of an enzyme is to increase the rate of a given reaction.

Question 66

During galactose catabolism, galactose 1-P and UDP-glucose yield intermediates: UDP-galactose and glucose 1-P.

a. True
b. False

Answer 66

a. True

Question 67

The use of fructose in glycolysis is inhibited by high glucagon levels.

a. True
b. False

Answer 67

b. False

Question 68

Please select the true statement:

a. Pyruvate carboxylase is a gluconeogenic enzyme that is used to bypass the glycolytic enzyme aldolase.
b. Carbon dioxide (as bicarbonate ion) is used as the carbon source to form oxaloacetate from pyruvate in the reaction catalyzed by pyruvate carboxylase.
c. The reaction catalyzed by pyruvate carboxylase yields ATP.
d. None of the statements above is true.

Answer 68

b. Carbon dioxide (as bicarbonate ion) is used as the carbon source to form oxaloacetate from pyruvate in the reaction catalyzed by pyruvate carboxylase.

Question 69

Please select the true statement:

a. Muscles and liver release free glucose for use by the brain and red blood cells.
b. The bacteria responsible for cat scratch fever, botulism, and gangrene are aerobic bacteria.
c. Glucagon inhibits gluconeogenesis and at the same time accelerates glycolysis in an example of reciprocal regulation.
d. None of the above is true.

Answer 69

d. None of the above is true.

Question 70

Please select the true statement:

a. Uncompetitive inhibitors bind to the formed enzyme-substrate complex (ES).
b. ∆G for a reaction is dependent on the final energy difference between the products and reactants, not the energy path between them.
c. Enzyme activity can be altered through reversible covalent modification.
d. All the above are true
e. Only a) and b) are true.
f. Only b) and c) are true.

Answer 70

d. All the above are true

Question 71

Which group of enzymes catalyze irreversible reactions during glycolysis?

a. Hexokinase, Phosphofructokinase 1, Pyruvate kinase
b. Hexokinase, Pyruvate kinase, Enolase
c. Phosphofructokinase 1, Phosphoglycerate kinase, Pyruvate kinase
d. Hexokinase, Phosphoglycerate kinase, Pyruvate kinase

Answer 71

a. Hexokinase, Phosphofructokinase 1, Pyruvate kinase

Question 72

How many carbons does the metabolite oxaloacetate contain?

a. = 2
b. = 3
c. = 4
d. = 5

Answer 72

c. = 4

Question 73

Please choose the true statement:

a. Sucrose is a disaccharide made up of glucose and mannose.
b. Lactose is a non-reducing disaccharide made up of galactose and glucose.
c. The anomeric carbon in aldose sugars is carbon 2.
d. There are no true statements here

Answer 73

d. There are no true statements here

Question 74

Please choose the true statement:

a. Isozymes are enzymes that are homologs that catalyze completely different reactions.
b. Enzymes bind to their substrates through a combination of many strong covalent and ionic interactions.
c. Binding of cyclic AMP (cAMP) inhibits protein kinase A (PKA).
d. None of the above is true.

Answer 74

d. None of the above is true.

Question 75

Identify the true statement

a. Thiamine pyrophosphate is a PDC cofactor that attaches lipoic acid to the amino group of lysine to form lipoamide.
b. Dihydrolipoamide is a cofactor that splits water in the the PDC.
c. The role of E3 in the PDC is to reactivate the enzyme complex by redox reactions
d. NADH is a prosthetic group of the PDC, whereas FADH2 leaves the PDC.

Answer 75

c. The role of E3 in the PDC is to reactivate the enzyme complex by redox reactions

Question 76

Which of the scenarios below correctly describes processes that occur to regulate glycolysis?

a. Pyruvate kinase is strongly activated by the glycolytic intermediate fructose 2, 6-bisphosphate in an example of feed-forward activation.
b. Glucokinase is inhibited through negative feedback by glucose 6-P
c. Fructose 2, 6-bisphosphate is a product of the first committed step of glycolysis
d. The adolase which cleaves fructose 1-P forms glyceraldehyde and dihydroxyacetone phosphate

Answer 76

d. The adolase which cleaves fructose 1-P forms glyceraldehyde and dihydroxyacetone phosphate

This aldol cleavage results in an unphosphorylated product, glyceraldehyde. This entry of fructose is not regulated, and can lead to ATP depletion through phosphorylation of glyceraldehyde.

Question 77

Please select the true statement:

a. Apo B100 and B47 are products of the same gene.
b. Chylomicrons primarily carry triacylglycerols of dietary origin.
c. As mature chylomicrons travel in the blood, they lose cholesterol through the action of lipoprotein lipase.
d. All the above are true.
e. Only a and c are true.
f. Only a and b are true.

Answer 77

b. Chylomicrons primarily carry triacylglycerols of dietary origin.

Question 78

Please select the true statement:

a. Oxaloacetate can be used to form glucose, nucleotides, and amino acids.
b. Anapleurotic reactions are anabolic reactions that restore substrates to the TCA cycle.
c. Alpha-ketoglutarate can be used to form nucleotides, and amino acids.
d. All the above are true.
e. Only a and b are true.
f. Only a and c are true.

Answer 78

d. All the above are true.

Question 79

Please select the true statement:

a. For glycogen phosphorylase b, the equilibrium between tense and relaxed state favors the relaxed state.
b. During glycogen synthesis, the glucose portion of CDP-glucose is transferred to C4 of the growing chain.
c. Glycogen phosphorylase releases glucose 1-P from the ends of straight chains of glycogen.
d. All the above are true.
e. There is no true statement here

Answer 79

c. Glycogen phosphorylase releases glucose 1-P from the ends of straight chains of glycogen.

Question 80

Please select the true statement:

a. Statins are competitive inhibitors of HMG CoA reductase
b. Familial hypercholesterolemia is generally a deficiency of the LDL receptor - not enough LDL receptors on the cell surface, and/or LDL receptors that are mutant and poorly functioning
c. VLDLs become IDLs as their density increases due to loss of cholesterol.
d. All the above are true.
e. Only a and b are true.
f. Only b and c are true.

Answer 80

e. Only a and b are true.

Question 81

Please select the true statement:

a. Binding of glucagon and epinephrine to their receptors causes an increase in glycogen synthase activity in the cell.
b. Calcium increase in the cell increases glycogen phosphorylase activity.
c. Binding of glucagon and epinephrine to their receptors cause an increase in glycogen phosphorylase kinase activity in the cell.
d. Only b and c are true.
e. Only a, and c are true

Answer 81

d. Only b and c are true.

Question 82

Please select the true statement:

a. The TCA cycle occurs in the cytoplasm in eukaryotes and prokaryotes.
b. Isocitrate undergoes oxidative decarboxylation to form alpha-ketoglutarate.
c. Both a and b are true
d. There are no true statements here

Answer 82

b. Isocitrate undergoes oxidative decarboxylation to form alpha-ketoglutarate.

Question 83

Please select the true statement:

a. There is only one function of the TCA cycle: to oxidize fuels for energy.
b. Succinyl CoA, produced by alpha-ketoglutarate dehydrogenase, is a substrate for ketone body synthesis.
c. Oxaloacetate can be formed by citrate synthase with citrate as the starting substrate.
d. There are no true statements here.

Answer 83

d. There are no true statements here.

Question 84

Please select the true statement:

a. The electron transport chain (ETC) includes malate dehydrogenase.
b. All four protein complexes of the ETC pump protons.
c. The electrons form FADH2 leave succinate dehydrogenase, to enter the ETC, by reducing ubiquinone
d. There are no true statements here.

Answer 84

c. The electrons form FADH2 leave succinate dehydrogenase, to enter the ETC, by reducing ubiquinone

Question 85

The pH of the mitochondrial intermembrane space is lower than that of the matrix.

a. True
b. False

Answer 85

a. True

Question 86

In one complete forward turn of the TCA cycle, what happens?

a. Four NADH are produced
b. One ATP or GTP is produced
c. One FADH2 is produced
d. All of the above are true
e. Only b and c are true.

Answer 86

e. Only b and c are true.

Question 87

Please select the true statement:

a. Aconitase catalyzes a reaction to form isocitrate from citrate.
b. Fumarase catalyzes the hydration of fumarate to form malate.
c. Citrate synthase is activated by succinyl CoA.
d. All the above are true
e. Only a and b are true.

Answer 87

e. Only a and b are true.

Question 88

Which of the following is a correct progression in the forward direction with no gaps:

a. Citrate synthase, Alpha-ketoglutarate dehydrogenase, Isocitrate dehydrogenase.
b. Alpha-ketoglutarate dehydrogenase, Succinate dehydrogenase, Fumarate
c. Succinate dehydrogenase, Fumarase, Malate dehydrogenase
d. Citrate synthase, Fumarase, Malate dehydrogenase
e. Succinyl CoA synthetase, Citrate synthase, Fumarate
f. Alpha-ketoglutarate dehydrogenase, Citrate synthase, Fumarate
g. Malate dehydrogenase, Fumarase, Oxaloacetate synthase

Answer 88

c. Succinate dehydrogenase, Fumarase, Malate dehydrogenase

Question 89

In proceeding from a 12 carbon to a 16 carbon fatty acid, during fatty acid synthesis as catalyzed by fatty acid synthase, which of the following would be an activated substrate used in the condensation reaction:

a. Malonyl ACP
b. Succinyl ACP
c. Acetyl ACP
d. ATP

Answer 89

a. Malonyl ACP

Question 90

18: 2 ∆9 ∆12 is an omega-3 fatty acid.
a. True
b. False

Answer 90

b. False

Question 91

Please select the true statement:

a. Complex II is reduced by ubiquinone.
b. Complex IV oxidizes molecular H2O
c. Complex III is oxidized by Cytochrome C
d. All the above are true.
e. Only a and b are true.

Answer 91

c. Complex III is oxidized by Cytochrome C

Question 92

The P/O ratio = the number of moles of ATP produced per mole of oxygen consumed. Which of the following is true:

a. The P/O ratio for FADH2 is 2
b. The P/O ratio for FADH2 is 2.5
c. The P/O ratio for FADH2 is 1
d. The P/O ratio for FADH2 is 0.5
e. The correct ratio is not shown.

Answer 92

e. The correct ratio is not shown.

Question 93

If mitochondria were poisoned by oligomycin, which of the following would occur:

a. Oxygen consumption would slow and stop as the proton gradient becomes too high.
b. Complex II would be in the oxidized state.
c. Complex IV would be in the oxidized state.
d. ATP synthase would still be producing ATP
e. All the above are true

Answer 93

a. Oxygen consumption would slow and stop as the proton gradient becomes too high.

Question 94

If mitochondria were poisoned by cyanide, which of the following would occur:

a. Complex IV would be poisoned directly
b. Complex III would be poisoned directly
c. Complex I would be poisoned directly
d. ATP synthase would be poisoned directly

Answer 94

a. Complex IV would be poisoned directly

Question 95

Please select the true statement:

a. Acetyl CoA carboxylase catalyzes the rate-limiting step of cholesterol synthesis.
b. Citrate activates acetyl CoA carboxylase.
c. Phosphorylation of acetyl CoA carboxylase increases the activity of this enzyme.
d. There are no true statements here

Answer 95

b. Citrate activates acetyl CoA carboxylase.

Question 96

Please select the true statement:

a. Linoleate is a saturated fatty acid that is produced in humans.
b. Palmitate is a 20 carbon saturated fatty acid that is the main product of fatty acid synthase.
c. Fatty acid synthesis occurs primarily in the cytosol.
d. There are no true statements here

Answer 96

c. Fatty acid synthesis occurs primarily in the cytosol.

Question 97

Please select the true statement:

a. Cholesterol is a starting substrate for bile salt synthesis
b. Cholesterol is a starting substrate for progesterone synthesis.
c. Cholesterol is produced from activated 5-carbon isoprene units.
d. Only a and c are true.
e. Only a, b, and c are true.

Answer 97

e. Only a, b, and c are true.

Question 98

Please select the true statement:

a. Fats are another term for lipids, and include fatty acids, triacylglycerol and phospholipids
b. Most of the glucose stored by our bodies is in the form of triacylglycerols.
c. Triaclyglycerols yield a greater quantity of ATP per gram than glycogen.
d. None of these statements is true.

Answer 98

c. Triaclyglycerols yield a greater quantity of ATP per gram than glycogen

Question 99

Please select the true statement:

a. From a 20C saturated fatty acid, 10 acetyl CoA would be produced during catabolism.
b. From a 20C mono-unsaturated fatty acid, 8 FADH2 would be produced during catabolism.
c. From a 16C mono-unsaturated fatty acid, 9 NADH would be produced during catabolism.
d. All the above are true.
e. Only a and b are true.
f. None of these statements is true.

Answer 99

e. Only a and b are true.

Question 100

Please select the true statement:

a. Regulation of fatty acid synthesis occurs through the regulation of carnitine acyltransferase I.
b. Fatty acid beta-oxidation occurs primarily in the mitochondrion.
c. Fatty acid beta-oxidation occurs primarily in the endoplasmic reticulum.
d. None of these statements is true

Answer 100

b. Fatty acid beta-oxidation occurs primarily in the mitochondrion

Question 101

Please select the true statement:

a. Regulation of the oxidative pentose phosphate pathway occurs chiefly through the regulation of glucose 6-P dehydrogenase.
b. The oxidative pentose phosphate pathway synthesizes 2 moles of mevalonate for every mole of glucose 6-P that enters.
c. The non-oxidative pentose phosphate pathway produces 2 moles of NADPH for every mole of glucose 6-P that enters this pathway.
d. All the above are true.

Answer 101

a. Regulation of the oxidative pentose phosphate pathway occurs chiefly through the regulation of glucose 6-P dehydrogenase.

Question 102

Please select the true statement:

a. The rate-limiting step of cholesterol synthesis occurs in the cytosol.
b. Unlike the TCA cycle, in the glyoxylate cycle, isocitrate does not undergo an oxidative decarboxylation, but instead is cleaved to form glyoxylate and succinate. For this reason acetyl CoA can be used to make glucose in organisms that have this cycle.
c. Cholesterol is catabolized in the mitochondrion to yield 15 molecules of acetyl CoA.
d. All the above are true.
e. Only a and b are true

Answer 102

e. Only a and b are true

Question 103

Catabolism of odd-number fatty acids:

a. Produces acetyl CoA, propionyl CoA, D- and L-methylmalonyl CoA, and succinyl CoA
b. Requires cobalamin.
c. Requires biotin.
d. Requires formation of an alpha-ketoglutaryl CoA intermediate.
e. Only a, b and c are true.

Answer 103

e. Only a, b and c are true.

Question 104

Please select the true statement:

a. During fatty acid synthesis, NADPH is used in synthetic reductions.
b. LDL is produced in the small intestine to carry dietary cholesterol to the liver.
c. VLDLs are constructed in the liver, and the predominant lipid in these particles is cholesterol and cholesterol esters.
d. None of these statements is true

Answer 104

a. During fatty acid synthesis, NADPH is used in synthetic reductions.

Question 105

Cholesterol is a membrane lipid and can also be a precursor for glucose.

a. True
b. False

Answer 105

b. False

Question 106

In humans, fatty acids are broken down to produce glucose.

a. True
b. False

Answer 106

b. False

Question 107

Please select the true statement:

a. Circulating chylomicrons in the blood contain both CII and apolipoprotein and contain predominantly phospholipids.
b. CII is a protein that acts as a lipase.
c. Chylomicron remnants predominantly contain cholesterol and cholesterol esters.
d. None of these statements is true.

Answer 107

c. Chylomicron remnants predominantly contain cholesterol and cholesterol esters.

Question 108

Please select the correct immediate product for each enzyme (not downstream product)

a. Glycogen phosphorylase: glucose 6-P
b. Glycogen phosphorylase: glucose 1-P
c. Debranching enzyme: glucose 6-P
d. Debranching enzyme: glucose
e. Only a and c are true
f. Only b and c are true
g. Only a and d are true
h. Only b and d are true

Answer 108

h. Only b and d are true

Question 109

The correct progression of major intermediates in cholesterol synthesis

1. Squalene
2. Geranyl pyrophosphate
3. Lanosterol
4. Isopentenyl pyrophosphate
5. Farnesyl pyrophosphate
6. Mevalonate

a. 1, 2, 3, 4, 5, 6
b. 6, 4, 1, 5, 3, 2
c. 6, 1, 2, 4, 5, 3
d. 6, 4, 2, 5, 1, 3

Answer 109

d. 6, 4, 2, 5, 1, 3

Question 110

Tay-Sachs disease is caused by a defect in fatty acid synthesis.

a. True
b. False

Answer 110

b. False

Question 111

Please select the true statement:

a. Ketone bodies are generally produced from acetyl CoA when the body is in a starved state due to lack of carbohydrates, or when insulin response is defective.
b. The three ketone bodies are acetoacetate, ubiquinone, and 3-hydroxy-3-methylglutaryl CoA
c. When the body is starved for carbohydrates, it will engage in triacylglycerol, fatty acid, and protein synthesis.
d. All the above are true.
e. Only a and b are true.
f. Only a and c are true.

Answer 111

a. Ketone bodies are generally produced from acetyl CoA when the body is in a starved state due to lack of carbohydrates, or when insulin response is defective.

Question 112

When do cells use the non oxidative pentose phosphate pathway in reverse? When the cell is in need of:

a. ATP.
b. NADPH.
c. Both NADPH and ATP
d. Nucleotides

Answer 112

d. Nucleotides

Question 113

Glycogenin is:

a. An enzyme that produced by the pancreas in response a large carbohydrate meal
b. A hormone released by the pancreas in response to low blood sugar.
c. A protein that is a place for attachment for glucose during the synthesis of new glycogen particles.
d. A protein that assists the enzyme glycogen synthase, by acting as a coenzyme.

Answer 113

c. A protein that is a place for attachment for glucose during the synthesis of new glycogen particles.

Question 114

Favism is a condition resulting from a deficiency in glucose 6-phosphatase.

a. True
b. False

Answer 114

b. False

Question 115

Activation of the glucagon receptor in the liver results in activation of adenylate cyclase.

a. True
b. False.

Answer 115

a. True

Question 116

Please select the following to make a true statement: In the malate-aspartate shuttle…

a. malate is oxidized to form oxaloacetate.
b. when alpha-ketoglutarate receives an amino group from aspartate, this alpha-ketoglutarate becomes alanine.
c. when oxaloacetate receives an amino group, this oxaloacetate is transformed to aspartate.
d. Only a and c are true.
e. Only a and b are true
f. None of the above is true

Answer 116

d. Only a and c are true.

Question 117

For the equation ∆G˚´ = - nF∆Ε´0, please define the following:

a. n = moles of reductant.
b. E´ = reduction potential.
c. F = number of electrons.
d. All the above are true.
e. Only a and c are true.

Answer 117

b. E´ = reduction potential.

Question 118

Please select the true statement:

a. Sphingolipids, in general, are highly represented in the membranes of tissues in the central nervous system.
b. To form phospholipids, phosphatidate can accept an activated alcohol head group, such as inositol, which has been phosphorylated by ATP and then activated by UTP.
c. Phosphatidylcholine and phosphatidylethanolamine are examples of phospholipids with a sphingosine backbone.
d. All the above are true.
e. Only a and b are true.
f. Only a and c are true.

Answer 118

a. Sphingolipids, in general, are highly represented in the membranes of tissues in the central nervous system.