19. Which of the following is (are) NOT found as covalently attached anchors in lipid-linked proteins?
(A) isoprenoid groups
(B) fatty acids
(C) cholesterol and other sterols
(D) glycosylphosphatidyl inositol groups
(E) All of the above are found as covalently attached anchors in lipid-linked proteins.

15. A researcher is analyzing the immune response of a patient following the patient's exposure to an unknown agent while out of the country. The patient's blood is found to have a high proportion of lymphocytes with CD8 surface proteins. What is the likely cause? (A) The patient encountered a bacterial infection which elicited CD8 marked T cells. (B) The disease must have been caused by a multicellular parasite, such as can be encountered in polluted water sources. (C) The CD8 proteins would be discharged from these lymphocytes to lyse the infected cells. (D) The CD8 proteins marked the surfaces of cytotoxic 'T cells to attack virus-infected host cells. (E) CD8 marks the surface of cells that accumulate after the infection is over and signal patient recovery.

16. What is the name of the protein that is used to form the initial glycogen primer? (A) phosphoporin (B) glucokinase (C) glycoporin (D) glycogenin (E) pyrophorin

17. Which of the following pairs of amino acids could form electrostatic interactions by their side chains? (A) Serine and phenylalanine (B) Glutamic acid and arginine (C) Alanine and glutamine (D) Leucine and cysteine (E) Histidine and Isoleucine

18. In humans, gluconeogenesis: (A) can result in the conversion of protein into blood glucose. (B) helps to reduce blood glucose after a carbohydrate-rich meal. (C) is activated by the hormone insulin. (D) is essential in the conversion of fatty acids to glucose. (E) requires the enzyme hexokinase.

20. Aspirin inhibits the synthesis of which of the following sets of eicosanoids? (A) Prostaglandin E2 and leukotriene A4 (B) Thromboxane A2 and leukotriene C4 (C) Prostaglandin F2 and thromboxane A2 (D) Prostaglandin A2 and 5-hydroperoxyeicosatetraenoic acid (E) Thromboxane A2 and 5-hydroperoxyeicosatetraenoic acid

21. In which metabolic pathway does glucose-6-phosphate dehydrogenase play a key role? (A) glycogenesis (B) glycolysis (C) gluconeogenesis (D) glycogenolysis (E) pentose phosphate pathway

22.Which of the following explains are the enzyme effects? (A) Enzymes release products very rapidly (B) Enzymes can lower product energy (C) An enzyme stabilizes the transition state of the reaction (D) An enzyme can convert a normally endergonic reaction into an exergonic reaction (E) An enzyme lowers the energy of activation only for the forward reaction

23. Enzymes are biological catalysts that enhance the rate of a reaction by: (A) decreasing the activation energy. (B) decreasing the amount of free energy released. (C) increasing the activation energy. (D) increasing the amount of free energy released. (E) increasing the energy of the transition state.

24. To determine the isoelectric point of a protein, first establish that a gel: (A) contains a denaturing detergent that can distribute uniform negative charges over the protein's surface. (B) exhibits a stable pH gradient when ampholytes become distributed in an electric field. (C) is washed with an antibody specific to the protein of interest. (D) neutralizes all ionic groups on a protein by titrating them with strong bases. (E) relates the unknown protein to a series of protein markers with known molecular weights, Mr.

25 Which of the following lipids can be formed by the methylation of phosphatidylethanolamine? (A) Phosphatidylinositol (B) Phosphatidylcholine (C) Phosphatidylserine (D) Sphingomyelin (E) Lysophosphatidylcholine