7. Answer is A. Cytochromes are protien containing iron or heme groups and function as electron transfer agents in many metabolic pathways in mitochondria and chloroplasts. It doesn\'t pump ATP, It doesn\'t has sulfur groups and it doesn\'t reduce oxygen to water. 8. Answer is B. Pyruvate to is converted to acetyl-coA by pyruvate dehydrogenase complex. First Pyruvate is decarboxylated by pyruvate dehydrogenase with help from TPP. Then dihydrolipoyl transacetylase with cofactor lipoamide oxidizes hydroxyethyl- to acetyl- and then transfers acetyl- to CoA, forming acetyl-CoA. Finally dihydrolipoyl dehydrogenase oxidizes the thiol groups of the dihydrolipoamide back to lipoamide reducing NAD to NADH. 9. Answer is E. The strongest oxidizing agent is oxygen, the oxidation of reduced NADH by oxygen has potential difference of 1.136 V; the electron flow will be from the most negative system, which is the couple NAD+/NADH, to the least negative system which is the couple O2/H2O. Thus the oxidation of the reduced form, NADH,oxygen is a spontaneous and a slow reaction, unless enzymes are present to catalyze the reaction. Solution 7. Answer is A. Cytochromes are protien containing iron or heme groups and function as electron transfer agents in many metabolic pathways in mitochondria and chloroplasts. It doesn\'t pump ATP, It doesn\'t has sulfur groups and it doesn\'t reduce oxygen to water. 8. Answer is B. Pyruvate to is converted to acetyl-coA by pyruvate dehydrogenase complex. First Pyruvate is decarboxylated by pyruvate dehydrogenase with help from TPP. Then dihydrolipoyl transacetylase with cofactor lipoamide oxidizes hydroxyethyl- to acetyl- and then transfers acetyl- to CoA, forming acetyl-CoA. Finally dihydrolipoyl dehydrogenase oxidizes the thiol groups of the dihydrolipoamide back to lipoamide reducing NAD to NADH. 9. Answer is E. The strongest oxidizing agent is oxygen, the oxidation of reduced NADH by oxygen has potential difference of 1.136 V; the electron flow will be from the most negative system, which is the couple NAD+/NADH, to the least negative system which is the couple O2/H2O. Thus the oxidation of the reduced form, NADH,oxygen is a spontaneous and a slow reaction, unless enzymes are present to catalyze the reaction..

1. 7. Answer is A.
Cytochromes are protien containing iron or heme groups and function as electron transfer agents
in many metabolic pathways in mitochondria and chloroplasts. It doesn't pump ATP, It doesn't
has sulfur groups and it doesn't reduce oxygen to water.
8. Answer is B.
Pyruvate to is converted to acetyl-coA by pyruvate dehydrogenase complex. First Pyruvate is
decarboxylated by pyruvate dehydrogenase with help from TPP. Then dihydrolipoyl
transacetylase with cofactor lipoamide oxidizes hydroxyethyl- to acetyl- and then transfers
acetyl- to CoA, forming acetyl-CoA. Finally dihydrolipoyl dehydrogenase oxidizes the thiol
groups of the dihydrolipoamide back to lipoamide reducing NAD to NADH.
9. Answer is E.
The strongest oxidizing agent is oxygen, the oxidation of reduced NADH by oxygen has
potential difference of 1.136 V; the electron flow will be from the most negative system, which
is the couple NAD+/NADH, to the least negative system which is the couple O2/H2O. Thus the
oxidation of the reduced form, NADH,oxygen is a spontaneous and a slow reaction, unless
enzymes are present to catalyze the reaction.
Solution
7. Answer is A.
Cytochromes are protien containing iron or heme groups and function as electron transfer agents
in many metabolic pathways in mitochondria and chloroplasts. It doesn't pump ATP, It doesn't
has sulfur groups and it doesn't reduce oxygen to water.
8. Answer is B.
Pyruvate to is converted to acetyl-coA by pyruvate dehydrogenase complex. First Pyruvate is
decarboxylated by pyruvate dehydrogenase with help from TPP. Then dihydrolipoyl
transacetylase with cofactor lipoamide oxidizes hydroxyethyl- to acetyl- and then transfers
acetyl- to CoA, forming acetyl-CoA. Finally dihydrolipoyl dehydrogenase oxidizes the thiol
groups of the dihydrolipoamide back to lipoamide reducing NAD to NADH.
9. Answer is E.
The strongest oxidizing agent is oxygen, the oxidation of reduced NADH by oxygen has
potential difference of 1.136 V; the electron flow will be from the most negative system, which
is the couple NAD+/NADH, to the least negative system which is the couple O2/H2O. Thus the
oxidation of the reduced form, NADH,oxygen is a spontaneous and a slow reaction, unless
enzymes are present to catalyze the reaction.