Pyruvate Oxidation & Kreb's Cycle

Question 1

What kind of active transport moves pyruvate into the mitochondrial matrix

Answer 1

secondary activet transport

Question 2

oxidation of pyruvate generates what?

Answer 2

CO2
acetyl coenzyme A (acetyl-COA)
NADH

Question 3

where does pryuvate oxidation occurs

Answer 3

mitochondria in eukaryotes
cytosol in prokaryotes

Question 4

For each 3 carbon pyruvate molecule what is lost/formed

Answer 4

1 CO2
1 NADH
1 Acetyl-COA

Question 5

pyruvate oxidation removes ___ from pyruvate and oxides the remaining 2C fragment to an ________

Answer 5

CO2; acetyl group

Question 6

Carbon products of pyruvate oxidation are oxidized to ___ in the _____

Answer 6

CO2; citric acid cycle

Question 7

how many reactions are in the kreb’s cycle

Answer 7

8

Question 8

what are the products of the kreb’s cycle

Answer 8

CO2
3 NADH
1 FADH2
1 ATP (substrate-level phosphorlyation)

Question 9

What happens in step 1 of the Kreb’s cycle? (condensation)

Answer 9

2-carbon acetyl group carried by COA is transferred to oxaloacetate to form citrate by citrate synthase

Question 10

What happens in step 3 of the Kreb’s cycle? (first oxidation)

Answer 10

isocitrate is oxidized to alpha-ketoglutarate and one carbon is lost as CO2 and NAD+ is reduced to NADH and H+ by isocitrate dehydrogenase

Question 11

What happens in step 4 of the Kreb’s cycle? (second oxidation)

Answer 11

alpha-ketoglutarate is oxidized to succinyl COA and one carbon is lost as CO2 and NAD+ is reduced to NADH and H+ by alpha-ketoglutarate dehydrogenase

Question 12

What happens in step 5 of the Kreb’s cycle? (substrate-level phosphorylation)

Answer 12

COA is released from succinate and this produces energy which is used to convert GDP to GTP and ADP to ATP by succinyl-CoA synthetase

Question 13

What happens in step 6 of the Kreb’s cycle? (third oxidation)

Answer 13

succinate is oxidized to fumarate. 2 electrons and 2 protons are removed and transferred to FAD to make FADH2 by succinate dehydrogenase

Question 14

What happens in step 7 of the Kreb’s cycle? (hydration reaction)

Answer 14

fumarate is converted to Malate by adding H2O by fumarase

Question 15

What happens in step 8 of the Kreb’s cycle? (fourth oxidation)

Answer 15

malate is oxidized to oxaoacetate, reducing NAD+ to NADH and H+ (can re-enter cycle) by malate dehydrogenase

Question 16

What happens in step 2 of the Kreb’s cycle? (isomerization)

Answer 16

citrate is rearranged to isocitrate by aconitase

Question 17

Glucose has been oxidized to

Answer 17

6 CO2
4 ATP
10 NADH
2 FADH2

Question 18

For Each Acetyl-COA entering….

Answer 18

2 CO2
3 NAD+ to 3 NADH
1 FAD to FADH2
1 ATP
regenerates oxaloacetate