Download Cellular Respiration Part 3

Cellular Respiration Part 3
Krebs Cycle – Pages 96 to 97
Chemically Grooming Pyruvate
• 3 steps to Krebs Cycle
▫ Carbon atom is removed (3C to 2C) and released
as CO2
▫ 2C compound is oxidized while NAD+ is reduced
to NADH
▫ Coenzyme A joins with 2C to form acetyl co-A
Fig. 9-10
CYTOSOL
MITOCHONDRION
NADH + H+
NAD+
2
1
Pyruvate
Transport
protein
3
CO2
Coenzyme A
Acetyl
CoA
Krebs Cycle (Citric Acid Cycle)
• Called the Citric Acid Cycle because Citric Acid (citrate)
is the 1st molecule formed in the cycle
• Called the Krebs Cycle after Hans Krebs – the researcher
who discovered it
• Occurs in the matrix of the mitochondria
• Involves 2 electron carriers – NADH and FADH2
• The cycle oxidizes organic fuel derived from pyruvate,
generating 1 ATP, 3 NADH, and 1 FADH2 per turn
Fig. 9-11
Pyruvat
e
CO2
NAD+
CoA
NADH
+ H+
Acetyl CoA
CoA
CoA
Citric
acid
cycle
2 CO2
FADH2
3 NAD+
3 NADH
FA
D
+ 3 H+
ADP
+
ATP
Pi
Summary of Krebs Cycle
• 2C of acetyl Co-A joins with 4C of OAA to form
6C citrate; Co-A is recycle
• Thru a series of energy extracting reactions
2CO2, 3NADH, 1FADH2 + 1 ATP are produced
per turn
• Remaining 4C molecule is rearranged to form
OAA
Fig. 9-12-8
Acetyl CoA
Products for 1
turn including
grooming:
4 NADH
1 FADH2
1 ATP
3 CO2
CoA—SH
NADH
+H
NAD
H2O
1
+
+
8
Oxaloacetate
2
Malate
Citrate
Isocitrate
NAD
H2O
+
Citric
acid
cycle
7
Fumarate
6
3
CO2
CoA—
SH
4
CoA—
SH
5
FADH2
NAD
FAD
+
Succinate
GTP
Pi
GDP
ADP
ATP
NADH
+ H+
Succinyl
CoA
NADH
+
H+
-Ketoglutarate
CO2
Products for
1 glucose
including
grooming:
8 NADH
2 FADH2
2 ATP
6 CO2