Pyruvate Oxidation and Krebs

Question 1

5 Steps of pyruvate oxidation

Answer 1

1. Pyruvate molecules enter matrix w help of membrane carrier
2. Coenzyme A attaches to the acetyl group of pyruvate molecule, which oxidizes, while NAD+ is reduced and becomes NADH
3. The remaining carboxyl group is removed as waste in the form of CO2
4. Resulting product acetyl co A
5. When energy is needed acetyl-coA enters Krebs cycle to continue aerobic respiration

Question 2

Definition of Krebs cycle

Answer 2

3rd stage in cellular respiration
Cyclical series of 8 reactions in order to transfer energy from organic molecules into useable forms for cell such as ATP, NADH, and FADH2 @ the same time releasing CO2 waste

Question 3

Steps 1-4 Krebs cycle

Answer 3

1. Acetyl coA reacts with oxaloacetate to form citrate. The coA is removed
2. Citrate undergoes an isomerization to form isocitrate
3. Through redox reaction isocitrate is oxidized to become ➰ketogluterate and an NAD+ ion from the matrix is reduced, gaining electrons to form an energy coenzyme NADH
4. ➰-ketogluterate forms succinyl coA by binding with coA and being oxidized by NAD+, which is reduced to NADH, while co2 is removed

Question 4

Steps 5 Krebs cycle

Answer 4

Succinyl-coA loses its coA (major energy) to become succinate, but not before some phosphorylations take place. Phosphate from the matrix displaces the coA, GDP is phosphorylated to become GTP; then the phosphate group is transferred to ADP to create ATP

Question 5

Steps 6-8 Krebs cycle

Answer 5

6. Another ion from the matrix, FAD, oxidizes succinate, to form another energy coenzyme, FADH2. This results succinate becoming fumarate
7. Water is added to fumarate to form malate
8. Malate undergoes one more redox reaction with NAD+ to produce NADH and oxaloacetate, ready for the cycle to begin again

Question 6

What does the Krebs cycle produce ?

Answer 6

6 NADH
2ATP
2FADH(2)

For each molecule of glucose that enters