Acetyl CoA and ETC PART 1 AND 2

Question 1

Acetyl CoA

Answer 1

Acetyl ESTER of Coenzyme A

Question 2

Key substance in numerous other biological pathways

Answer 2

Acetyl Coenzyme A

Question 3

Acetyl CoA

Answer 3

A thioester

Question 4

The metabolically ACTIVE FORM OF CARBOXYLIC ACID is the corresponding ACYL-CoA thioester, in which the thioester linkage is a

Answer 4

High-energy bond

Question 5

Straight chain hydrocarbon

Answer 5

Acyl

Question 6

-COOH

Answer 6

Carboxylic acid

Question 7

STAGE 3

Answer 7

Citric acid cycle

Question 8

Citric acid cycle

Answer 8

• operates under AEROBIC conditions only
• Oxidizes the two-carbon acetyl group in acetyl CoA to 2CO2
• Produces REDUCED COENZYMES NADH and FADH2 and 1 ATP directly

Question 9

In the citric acid cycle,

Answer 9

• Acetyl (2C) bonds to oxaloacetate (4C) to form citrate (6C)
• Oxidation and decarboxylation reactions convert citrate to OXALOACETATE
• Oxaloacetate bonds with another acetyl to REPEAT THE CYCLE

Question 10

Citrate to form

Answer 10

Alpha ketoglutarate

Question 11

Alpha ketoglutarate to form

Answer 11

Succinyl CoA

Question 12

Succinyl CoA to form

Answer 12

Oxaloacetate

Question 13

1. Citrate
2. Isocitrate
3. a-ketoglutarate
4. Succinyl CoA
5. Succinate
6. Fumarate
7. Malate
8. Oxaloacetate

Answer 13

Tricarboxylic Acid Cycle

Question 14

Combines with the TWO-CARBON ACETYL group to form CITRATE

Answer 14

Oxaloacetate

Question 15

Isomerizes to isocitrate

Answer 15

Citrate

Question 16

Has a TERTIARY -OH group converted to a SECONDARY -OH in isocitrate that can be oxidized

Answer 16

Citrate

Question 17

Enzyme of citrate to isocitrate

Answer 17

Aconitase

Question 18

Reaction 1: Formation of CITRATE
Reaction 2: Isomerization to ISOCITRATE
Reaction 3: Oxidative Decarboxylation (isocitrate)
Reaction 4: Oxidative Decarboxylation (a-ketoglutarate
Reaction 5: Hydrolysis (Succinyl CoA)
Reaction 6: Dehydrogenation (Succinate)
Reaction 7: Hydration of Fumarate
Reaction 8: Dehydrogenation (Malate)

Question 19

Isocitrate

Answer 19

• Undergoes DECARBOXYLATION (carbon removed as CO2)
• Oxidizes the -OH to a KETONE releasing H+ and 2e-
• Provides H to reduce coenzyme NAD+ to NADH

Question 20

a-ketoglutarate

Answer 20

• Undergoes DECARBOXYLATION to form SUCCINYL CoA
• Produces a 4-CARBON compound bonds to CoA
• Provides H+ and 2e- to reduce NAD+ to NADH

Question 21

Succinyl CoA

Answer 21

• Undergoes HYDROLYSIS of the thioester bond
• Provides ENERGY to add phosphate to GDP and form GTP, a high energy compound

Question 22

Succinate

Answer 22

• Undergoes DEHYDROGENATION
• Loses 2 H and forms a DOUBLE BOND
• Provides 2H to reduce FAD to FADH2

Question 23

Fumarate

Answer 23

• Undergoes HYDRATION
• Adds WATER to the double bond
• is converted to MALATE

Question 24

Malate

Answer 24

• Undergoes DEHYDROGENATION
• Forms OXALOACETATE with a C=O double bond
• Provides 2H that reduce NAD+ to NADH + H+

Question 25

Summary of citric acid cycle

Answer 25

- An acetyl group bonds with OXALOACETATE to form CITRATE - 2 DECARBOXYLATIONS remove 2 CARBONS as 2CO2 - 4 OXIDATIONS provide HYDROGEN for 3NADH and 1 FADH2 - A direct phosphorylation forms GTP (ATP)

Question 26

How many of each are produced in one turn of the citric acid cycle?

Answer 26

2 CO2 3 NADH 1 FADH 1 GTP