BIOCHEM EXAM 4

4. What type of pathway can be either anabolic or catabolic depending on the energy conditions of the cell? a. amphipathic b. amphiprotic c. Amphibolic d. amphoteric e. hydrolytic

Amphibolic

Which chemical uncouples electron transport from ATP synthesis? a. 2,4-dinitrophenol (DNP) b. dicyclohexylcarbodiimide (DCC) c. oligomycin d. carbon monoxide (CO) e. cyanide CN-

a. 2,4-dinitrophenol (DNP)

What reactions are used to replenish citric acid cycle intermediates after they are depleted by biosynthetic pathways? a. Anaplerotic b. amphibolic c. amphoteric d. biosynthetic e. cataplerosis

a. Anaplerotic

What class of enzymes catalyzes the reaction of transferring a phosphoryl group from ATP to acceptor? a. Kinases b. phosphatases c. phosphorylases d. hydrolases e. amylases

a. Kinases

What organ controls the level of glucose in blood? a. Liver b. kidneys c. muscles d. adipose tissue e. nerve system

a. Liver

What catalyzes the reaction of ATP regeneration from ADP every time we exercise strenuously? a. creatine kinase b. nucleoside monophosphate kinase c. nucleoside diphosphate kinase d. aldolase

a. creatine kinase

What enzyme scavenges superoxide radicals by catalyzing the conversion radicals into hydrogen peroxide and molecular oxygen? a. superoxide dismutase b. catalase c. glutathione peroxidase d. glutathione-S-transferase e. tocopherol

a. superoxide dismutase

Choose the components of the citric acid cycle that can be used to synthesize amino acids. a. α-ketoglutarate and oxaloacetate b. citrate and succinyl CoA c. isocitrate and oxaloacetate d. succinate and L-malate e. succinate and fumarate

a. α-ketoglutarate and oxaloacetate

What is the main role of the proton gradient? a. ATP synthesis b. ATP release from the synthase c. coupling of ATP synthesis and respiration d. Q-cycle occurrence e. membrane charging

b. ATP release from the synthase

What is the primary role of catabolism? a. generation of complex structures from simple ones b. generation of ATP c. generation of acetyl CoA d. degradation of biomolecules e. active transport

b. generation of ATP

Approximately how many ATP or GTP equivalents will be produced from fuel molecules during one turn of the citric acid cycle? a. 6 b. 9 c. 10 d. 12 e. 38

c. 10

In animals, the carbon backbone of glucose _____ be metabolically converted and stoichiometrically utilized for synthesis of fatty acids; in animals, the carbon backbone of fatty acids _____ be metabolically converted and stoichiometrically utilized for synthesis of glucose. a. Can; can b. Can only; can only c. Can; cannot d. Cannot; can e .Cannot; cannot

c. Can; cannot

What is the function of a thioester intermediate such as the one formed from GAP? a. It speeds up the actual reaction so that more product can be made. b. The thioester shifts the equilibrium of the first stage of the reaction. c. The thioester allows the two-step reaction to be coupled so phosphorylation can proceed. d. The thioester intermediate induces a conformational change that alters enzyme specificity. e. The thioester prevents the formation of metabolically unfavorable side products

c. The thioester allows the two-step reaction to be coupled so phosphorylation can proceed.

What is the result of the reaction sequence of glycolysis, where glucose undergoes a phosphorylation, an isomerization, and a second phosphorylation? a. formation of glucose 6-phosphate b. formation of fructose 6-phosphate c. formation of fructose 1,6-bisphosphate d. isomerization of glucose 6-phosphate to fructose 6-phosphate e. isomerization of fructose 6-phosphate to glucose 6-phosphate

c. formation of fructose 1,6-bisphosphate

What is the allosteric stimulator of pyruvate kinase? a. ADP b. pyruvate c. fructose 1,6-bisphosphate d. fructose 2,6-bisphosphate e. ATP

c. fructose 1,6-bisphosphate

What molecule inhibits hexokinase activity? a. glucose b. fructose 6-phosphate c. glucose 6-phosphate d. fructose 1,6-bisphosphate e. fructose 2,6-bisphosphate

c. glucose 6-phosphate

According to the acceptor control mechanism, the rate of respiration depends on the level of what substance? a. fructose b. NADPH c. glucose d. ADP e. ATP

d. ADP

What is the ultimate product of oxidation in aerobic organisms? a. O2 b. H2O c. pyruvate d. CO2 e. lactate

d. CO2

Overconsumption of which monosaccharide may lead to obesity, fatty liver, and insulin insensitivity? a. lactose b. glucose c. galactose d. fructose e. sucrose

d. Fructose

What enzyme of the glyoxylate cycle catalyzes a condensation of acetyl CoA and glyoxylate? a. aconitase b. citratesynthase c. isocitrate lyase d. malate synthase e. malatedehydrogenase

d. malate synthase

What are the components of glyceraldehyde 3-phosphate dehydrogenase's active site? a. reactive histidine residue and NADH with cysteine b. reactive cysteine residue and NADH with histidine c. reactive histidine residue and NAD+ with cysteine d. reactive cysteine residue and NAD+ with histidine e. reactive cysteine residue and ATP with histidine

d. reactive cysteine residue and NAD+ with histidine

Metabolic processes are regulated by a. Allosteric control b. Feedback Inhibition c. Covalent modification d. A & B e. A, B & C

e. A, B & C

What is the "chemical currency" of metabolism? a. NADH b. acetyl CoA c. NADPH d. glucose e. ATP e. amylases

e. ATP

The first control site in the Krebs cycle is inhibited by: a. acetyl CoA. b. ADP. c. Mg2+. d. NAD+ . e. NADH.

e. NADH.

The first control site in the Krebs cycle is inhibited by: a. acetyl CoA. b. ADP. c. Mg2+. d. NAD+ . e. NADH.

e. NADH.

Which intermediate is found at the traditional start and finish point of the citric acid cycle? a. citrate b. isocitrate c. α-ketoglutarate d. succinate e. Oxaloacetate

e. Oxaloacetate