Questions 1-15 (4 pts. each): Multiple choice 1. When hexokinase phosphorylates glucose to glucose-6-phosphate A) the reaction is endergonic B)two ATPs are used C)the phosphorylated glucose can no longer leave the cell D) the glucose-6-phosphate can then rearrange to galactose-6-phosphate E) None of the above 2. The enzyme triosephosphate isomerase has histidine and glutamic acid sidechains in its active site, both of which help catalyze the conversion of DHAP to GAP. Which of the following statements is true? A) The enzyme catalyzes the conversion of DHAP to GAP but not the conversion of GAP to DHAP B) The histidine acts as a base abstracting a proton from the carbon of the substrate and the glutamic acid acts as an acid protonating the oxygens. C) The histidine is phosphorylated at the active site. D) The glutamic acid acts as a base abstracting a proton from the carbon of the substrate and the histidine acts as an acid protonating the oxygens. E) None of the above 3. The enzyme 3-phosphoglycerate kinase catalyzes one of the ATP-generating steps in glycolysis. Using Table 15.1 (on the front page), determine the AG°” (under standard conditions) A) +30.5 kJ/mol B)30.5 kJ/mol C) +18.9 kJ/mol D) 18.9 kJ/mol E)-0 kJ/mol 4. In glycolysis, if glucose is labeled at the carbon 6 position (see page 1 for numbering of carbons in glucose) A) B) C) D) E) the carbon with the OH on it in DHAP is labeled the carbon with the -O on it in GAP is labeled both the carbon with the-O on it in DHAP and the carbon with the OH on it in GAP are labeled the carbon with the low-energy phosphate on it in 1,3 BPG is labeled the label is lost before pyruvate is 5. When pyruvate labeled at the carbonyl carbon (carbon 2) is reacted with pyruvate carboxylase in luconeogenesis A) the label is released as CO2 B)the label ends up as the carbon that is phosphorylated in PEP C)the label becomes one of the two carboxyl groups in oxaloacetate D) the label becomes the acetyl group in acetyl CoA E) he label becomes the methyl group in acetyl CoA