5.3- Citric Acid Cycle Cell Respiration

Pyruvate decarboxylation:

• if oxygen is present, pyruvate is converted into acetyl CoA in the mitochondrial matrix

- Per molecule of glucose:

• 2 Pyruvate ➞ 2 Acetyl CoA+ 2 NADH + 2 CO2

• Process happens 2x

Is Pyruvate decarboxylation aerobic or anaerobic

• Aerobic

Purpose of Pyruvate decarboxylation:

• Synthesis of acetyl-CoA

Citric Acid Cycle produces ATP via…

• Substrate level phosphorylation

Where is the Citric Acid Cycle taking place?

• Mitochondrial Matrix

Citric Acid Cycle Summarized

Acetyl CoA from pyruvate decarboxylation merges with oxaloacetate to form citrate ➞ citrate undergoes 7 more steps, forming different intermediates ➞ oxaloacetate is reformed ➞ cycle repeats.

How many times does the cycle occur

• Cycle occurs twice per glucose molecule.

What does each cycle produce

- 1 GTP/ATP, 3 NADH, and 1 FADH2

- 2 CO2 are also produced per cycle.

• This is the CO2 exhaled during respiration.

One glucose molecule yields

6 NADH, 2FADH2, 2 ATP, and 4 CO2, from the CAC

NADH, FADH2 molecules that function as…

high energy electron carriers.

During glycolysis and CAC, glucose is stripped..

of high energy electrons and these carriers are reduced as they

gain the electrons:

• NAD+ ➞ NADH

• FAD ➞ FADH2

NADH and FADH2 then shuttle glucose’s electrons to the

ETC to create ATP.