Lecture 26: Citric Acid Cycle

Question 1

pyruvate enters the citric acid cycle after glycolysis if __ condition present

Answer 1

aerobic

Question 2

pyruvate is converted to __ in preparation for the citric acid cycleq

Answer 2

acetyl CoA

Question 3

in the citric acid cycle, acetyl CoA is transformed in energy precursors __ and __

Answer 3

NADH and FADH2

Question 4

electron transport from the energy precursors leads to the ___ to produce ATP

Answer 4

phosphorylation of ADP

Question 5

the main function of the citric acid cycle is to harvest __ from carbon fuels

Answer 5

high-energy electrons

Question 6

the citric acid cycle is the central pathway for ___ all metabolic fuels

Answer 6

oxidizing

Question 7

t/f citric acid cycle connects carbohydrate, fat, and protein metabolism

Answer 7

true

Question 8

most of the energy made from substrate oxidation in the citric acid cycle is stored in __

Answer 8

reduced electron carriers: NADH and FADH2

Question 9

how many (net) ATP are made per glucose in the citric acid cycle?

Answer 9

2

Question 10

how many ATP are made after the ETC for on glucose?

Answer 10

34

Question 11

another important role of the citric acid cycle is the production of intermediate compounds important in the making of things like __ and __

Answer 11

amino acids and fatty acids

Question 12

in eukaryotes, glycolysis occurs in the __

Answer 12

cytoplasm

Question 13

in eukaryotes, the Krebs cycle occurs in the

Answer 13

mitochondria

Question 14

in eukaryotes the ETC takes place in the __

Answer 14

inner crystal of the mitochondria

Question 15

in prokaryotes, all steps of metabolism occur in __ and __

Answer 15

cytoplasm and PM

Question 16

why is the Krebs cycle called a cycle?

Answer 16

b/c the starting material oxaloacetate is regenerated at the end of the cycle

Question 17

what is the first product of the Krebs cycle?

Answer 17

citric acid

Question 18

why is the Krebs cycle referred to as the trim-carboxylic acid cycle?

Answer 18

citric acid contains three carboxylic acid groups

Question 19

3C pyruvate is converted to 2 carbon that is linked to the coenzyme by the enzyme __

Answer 19

pyruvate dehydrogenase

Question 20

t/f pyruvate processing is a redox reaction

Answer 20

true

Question 21

what are the co-products of pyruvate processing?

Answer 21

CO2 and NADH

Question 22

coenzyme A is a __ molecule

Answer 22

high energy carrier

Question 23

t/f CoA carriers acetyl in both catabolic and anabolic processes

Answer 23

true

Question 24

the attachment of CoA to acetyl allows the acetyl to attach to

Answer 24

oxaloacetate

Question 25

from one citric acid cycle the following products are made:

Answer 25

1 ATP
3 NADH (+1 NADH from pyruvate oxidation)
1 FADH 
2 CO2
regenerated oxaloacetate

Question 26

how many rounds of the Krebs cycle,e are needed to completely oxidize one molecule of glucose?

Answer 26

2

Question 27

in an efficient cell, as many as __ ATP can be produced by cell respiration

Answer 27

38