25. Which step of the mitochondrial electron transport chain does rotenone inhibit?
(A) NADH → coenzyme Q
(B) Cyt b → Cyt c1
(C) Cyt c1 → Cyt c
(D) Cyt c → Cyt (a+a3)
(E) Cyt c → O₂

21. The binding change mechanism of ATP synthesis predicts that each 360-degree rotation of the γ subunit can generate how many ATP molecules? (A) 1 (B) 2 (C) 3 (D) 4 (E) 5

22. What is the net charge of the following peptide at pH 7.0?Tyr-Glu-Ser-Arg-Met-Thr-Asp-Asn-Tyr-His (A) +2 (B) +1 (C) 0 (D) -1 (E) -2

23. Which of the following molecules can generate the highest yield of ATP in the process from glycolysis to lactate? (A) sucrose (B) fructose (C) glucose 6-phosphate (D) dihydroxyacetone phosphate (E) glyceraldehyde 3-phosphate

24. Which method is used to predict the amino acid sequence of tryptic fragments by bioinformatic approaches? (A) sodium dodecyl sulfate polyacrylamide gel electrophoresis (B) Edman degradation (C) tandem mass spectrometry (D) two-dimensional polyacrylamide gel electrophoresis (E) gel-filtration chromatography

26. Regarding the chemiosmotic theory of the respiratory chain, which statement is TRUE? (A) Oxidative phosphorylation occurs in the outer mitochondrial membrane. (B) The proton (H+ ) concentration is the same on both sides of the inner mitochondrial membrane. (C) ATP synthase plays no role in the chemiosmotic theory. (D) Mitochondrial inner memebrane is permeable for proton. (E) ATP synthesis is related to proton-motive force.

27. Which of the following sets of amino acids are directly involved in the biosynthesis of creatine? (A) tyrosine, glycine, and glutamine (B) glutamate, cysteine, and glycine (C) glycine, arginine, and methionine (D) aspartate, glycine, and cysteine (E) proline, alanine, and leucine

28. Hydropathy plot is commonly used for ______. (A) predicting the quaternary structure of membrane proteins (B) measuring the water content of native proteins (C) estimating the actual molecular weight of membrane proteins (D) predicting whether a known protein amino acid sequence contains a membrane-spanning segment (E) analyzing protein secondary structure

29. What substance(s) can affect the concentration of calcium ions inside the cell, an important secondary messenger? (A) Phosphatidylcholine and phospholipase A (B) Phosphatidylcholine and phospholipase C (C) Phosphatidylinositol and phospholipase A (D) Phosphatidylinositol and phospholipase C (E) Calmodulin

30. Which statement is TRUE? (A) A higher Km value indicates a higher substrate specificity. (B) A higher Km value indicates a higher substrate affinity. (C) The unit for Km is M-1 s -1 . (D) kcat is the specificity constant. (E) kcat/Km is a measure of enzyme efficiency.

31. Which description about interaction between species is NOT true? (A) Predation: An individual of one species, the predator, kills and eats an individual of the other, the prey. (B) Parasitism: The parasite obtains its nourishment from a second organism, its host. (C) Competition: Indivisuals of different species each use a limited resourse, reducing the survival or reproductin of both individuals. (D) Commensalism: Members of both species benefit from the interaction. (E) Herbivory: An herbivore eats part of a plant or alga.