8. Iron deficiency in a cell can adversely affect electron transport at which of the following sites:
(A) Cytochrome b and cytochrome c.
(B) Coenzyme Q and FADH₂.
(C) NADH and FADH₂.
(D) Coenzyme Q and NADH.
(E) All sites in electron transport are affected.

4. Both water and glucose share an -OH that can serve as a substrate for a reaction with the terminal phosphate of ATP catalyzed by hexokinase. Glucose, however, is about a million times more reactive as a substrate than water. The best explanation is that: (A) Glucose has more -OH groups per molecule than does water. (B) The larger glucose binds better to the enzyme; it induces a conformational change in hexokinase that brings active-site amino acids into position for catalysis. (C) The -OH group of water is attached to an inhibitory H atom, while the glucose -OH group is attached to С. (D) Water and the second substrate, ATP, compete for the active site resulting in a competitive inhibition of the enzyme. (E) Water normally will not reach the active site because it is hydrophobic.

5. Which of the following is     not correct     concerning 2,3-bisphosphoglycerate (BPG)? (A) It binds at a distance from the heme groups of hemoglobin. (B) It binds with lower affinity to fetal hemoglobin than to adult hemoglobin. (C) It increases the affinity of hemoglobin for oxygen. (D) It is an allosteric modulator. (E) It is normally found associated with the hemoglobin extracted from red blood cells.

6. A monoclonal antibody differs from a polyclonal antibody in that monoclonal antibodies: (A) are labeled with chemicals that can be visualized. (B) are produced by cells from the same organism that produced the antigen. (C) are synthesized by a population of identical, or "cloned," cells. (D) are synthesized only in living organisms. (E) have only a single polypeptide chain that can recognize an antigen.

7. Which of the following statements of electron transport chain is     not true    ? (A) Complex I contains copper ions. (B) The final reduced species in the electron transport chain in mitochondria is H2O. (C) The P/O ratio refers to the number of moles of ATP produced for each mole of oxygen atoms consumed in electron transport. (D) Cytochrome c is a macromolecule which is loosely bound to the outer surface of the inner mitochondrial membrane. (E) None of the above.

9. Which one of the following statements about glycolysis is     correct    : (A) Conversion of glucose to glyceraldehyde-3-phosphate is an exergonic reaction. (B) Conversion of glucose-6-phosphate to fructose-6-phosphate is a cleavage reaction. (C) Conversion of glyceraldehyde-3-phosphate to give 1,3-bisphosphoglycerate is a dehydration reaction. (D) Conversion of dihyroxyacetone phosphate to glyceraldehyde-3-phosphate is an isomerization reaction. (E) Conversion of 2-phosphoglycerate to give phosphoenolpyruvate is an oxidation reaction.

10. Which one of the following is     not     associated with the oxidation of substrates by the citric acid cycle? (A) CO2 production. (B) Pyridine nucleotide oxidation. (C) Flavin reduction. (D) Lipoic acid present in some of the enzyme systems. (E) All of the above are involved.

11. Which one is     not     related with cardiovascular disease? (A) Cholesterol. (B) Caveolin. (C) Avastin. (D) HMG-CoA reductase. (E) Lovastatin.

12. Joseph intended to donate his blood after a meal, but was found with a milky blood. Which plasma lipoprotein might be responsible for this phenomenon? (A) Chylomicrons. (B) VLDL. (C) LDL. (D) HDL. (E) ACAT.

13. The compound that consists of deoxyribose linked by an N-glycosidic bond to N-1 of cytosine is: (A) a deoxyribonucleoside. (B) a purine nucleotide. (C) a pyrimidine nucleotide. (D) deoxycytidine monophosphate. (E) cytidine.

14. Deamination of the nucleotide base adenine yields nucleotide base: (A) xanthine. (B) inosine. (C) uracil. (D) hypoxanthine. (E) xanthylate.