4.2 (b) Flashcards
(12 cards)
1
Q
At the end of glycolysis
A
- 2 pyruvate is produced
- contains 75% of energy from glucose
2
Q
Pyruvate Oxidation
A
- Pyruvate must pass thru the inner and outer mitochondrial
membranes - Can cross out
- In order to cross inner membrane
- a pyruvate-specific membrane carrier is needed
an acetyl-
group temporarily bonded to a sulfur atom on Coenzyme A
(CoA)
* Acetyl-CoA complex is formed
3
Q
Pyruvate Oxidation - PT 2
IMAGE
A
- Converting pyruvate —> actyle group Reqiures decarboxylation rxn
(carboxyl group removed and CO2 forms as waste)
- Makes up 1/3 of Co2 removed as waste
- Followed by the oxidation of remaining 2 carbon molecules producing
an acetyl group
This dehydrogenation rxn trans fers 2e- and a proton to
NAD+ , forming NADH and releasing one proton into
sol’n
* Acetyl group reacts with sulphur atom of
Coenzyme A (CoA), forming the high-energy
Acetyl-CoA
4
Q
The Citric Acid Cycle
A
- 8 enzyme catalyst rxn
- Oxidation of acetyl groups to CO2
- Synthesis of ATP, NADH and FAD (the reduced form
is FADH2) - For each Acetyl-CoA (and there are two) that enters
- 3 NADH (therefore 6 NADH)
- 1 FADH2 (therefore 2 FADH2
) - 1 ATP (via substrate-level phosphorylation) (therefore 2 ATP)
5
Q
Step 1
A
oxaloacetate —> citrate
6
Q
Step 2
A
Citrate —> isomer isovcitrate
7
Q
Step 3
A
-isocitrate becomes oxidised
- Co2 released
- NAD reduced to NADH
8
Q
Step 4
A
- Co2 released
- NAD reduced to NADH
9
Q
Step 5
A
- The release of CoA from
Succinyl CoA produces
Succinate - Energy released converts
GDP to GTP, which in turn
converts ADP to ATP (via
substrate-level
phosphorylation) - Only ATP made
10
Q
Step 6
A
- FAD —> FADH
11
Q
Step 7
A
Fumarate—> malate with water added
12
Q
Step 8
A
- NAD —> NADH
- Malate is oxidized to
oxaloacetate, - Oxaloacetate can
react with acetyl-CoA
to re-enter the cycle
