Page 980 - Fundamentals of anatomy physiology

Chapter 25 Metabolism and Energetics 967

Figure 25–4 The Citric Acid Cycle.

Pyruvate

NAD Coenzyme A

CO2 NADH
Acetyl-CoA Coenzyme A

4-carbon Citrate
6-carbon

H CO2 H NADH ELECTRON TRANSPORT SYSTEM
5-carbon
CITRIC
2H ACID H NADH

CYCLE CO2 Pyruvate

4-carbon

ATP (by GTP) NAD C

FADH2 NADH C O
C OO–

NADH CO2

a An overview of the citric acid cycle, Acetyl-CoA C C CoA Coenzyme A
showing the distribution of carbon, O
hydrogen, and oxygen atoms through
one complete turn C OO– C OO–
C
OC HO C C OO–
C
NADH C OO– C C OO–
NAD C OO–
Oxaloacetate
Citrate C O O–
C C
HO C
C O O–
C OO–
HO C Isocitrate
C
C OO– NAD

Malate

H2O CITRIC C OO– NADH 25
ACID +
CYCLE
CO2

C OO– C
C
C O C
C C OO–
C OO–

Fumarate α –Ketoglutarate

Coenzyme A + NAD

FADH2

FAD C OO– Coenzyme A H2O C OO– NADH + CO2
GDP C
C C
C CO
C OO–

Succinate CoA
GTP Succinyl-CoA

b A detailed view of the citric acid cycle, ADP ATP
showing the changes in the carbon chain