SOLVED

61) The molecule on which an enzyme acts is commonly referred to as: A) reactant B) substrate C) hydrolate D) active site E) actor 62) Choose the INCORRECT statement about metabolism. A) Catabolism is when substances are broken down. B) Anabolism is the derivation of energy from substances. C) Metabolites are substances involved in metabolism. D) Endergonic reactions are nonspontaneous. E) Metabolism is the totality of an organism deriving energy from matter and excreting excess. 63) Find a mismatch enzyme – substrate pair. A) amylases – starch B) amylase – polysaccharides C) lipase – fats and oils D) pepsin – diglycerides E) trypsin and chymotripsin – polypeptides 64) Living cells are unable to convert glucose-6P i into which of the following? A) glycogen B) glucose C) coenzyme A D) polysaccharide stored in liver E) it may be metabolized 65) By definition, exergonic reaction has: A) ΔG= positive value B) ΔG= negative value C) ΔH= positive value D) ΔH= negative value E) ΔS = positive value 66) Find a mismatch in the following body part – food metabolism pairs: A) mouth – starch B) small intestine – polysaccharides C) small intestine – fats and oils D) stomach – proteins E) stomach – polypeptides 67) Which of the following represents an INCORRECT breakdown sequence for that food? A) carbohydrates – polysaccharides – coenzyme A B) starch – maltose and dextrins – maltose – glucose C) protein – polypeptides – small peptides – amino acids D) fats and oils – glycerol, glycerides, and fatty acids – fatty acids to CO2 and water E) fats and oils – glycerol, glycerides, and fatty acids – glycerol to triose phosphate 68) Apart from bringing the reactants close together, how does the binding of substrates in the active site of the enzyme serve to catalyze a reaction? A) Binding lowers the activation energy of the reaction. B) Enzymes provide energy upon substrate binding to drive the reaction. C) Binding of the substrate maintains the optimal temperature for the reaction. D) Binding maintains the optimal pH for enzyme activity. E) Binding lowers the energy of the products increasing the reaction rate. 69) Many insecticides contain compounds which inhibit the enzyme acetylcholine esterase which is essential for respiration and other vital functions in insects. These compounds exert their inhibitory effects by covalently bonding to active site amino acid side chains. What would be the most likely explanation for the inhibitory effects of these compounds? A) Bonding of these compounds denatures the enzyme disrupting its secondary and tertiary structure. B) Bonding changes the primary structure of the enzyme profoundly affecting the activity of the enzyme. C) These compounds compete for the active site of the enzyme where they bind covalently and block the subsequent binding of substrate molecules. D) Covalent bonding of these compounds changes the pI of the enzyme which causes it to become less soluble and precipitate. E) Bonding of these compounds raises the activation energy of the reaction catalyzed by the enzyme. 70) Which of the following combinations make up the nucleic acid, RNA? A) ribose and the bases A, G, U, C B) ribose and the bases A, G, T, C C) deoxyribose and the bases A, G, T, C D) deoxyribose and the bases A, G, U, C