Anaerobic Respiration

Question 1

What are the 2 types of anaerobic respiration (fermentation)

Answer 1

Ethanol fermentation
Lactate fermentation

Question 2

Products of ethanol fermentation

Answer 2

Ethanol, NAD, and CO2

Question 3

Products of lactate fermentation

Answer 3

Lactate & NAD

Question 4

What is different about anaerobic conditions compared to in aerobic

Answer 4

oxygen cannot act as the final electron acceptor
No ATP produced
Reduced NAD & FAD can’t be oxidised by electron carrier
-> Krebs cycle eventually stops, as does link reaction

Question 5

In anaerobic respiration, oxygen cannot act as the final electron acceptor
What does this mean in terms of what can’t occur

Answer 5

(So oxidative phosphorylation can’t occur [e- + H+ + O2 -> H2O])
-> therefore the protons involved in oxidative phosphorylation can’t react & accumulate in the matrix

Question 6

In anaerobic respiration, reduced NAD & FAD can’t be oxidised by electron carrier
What does this mean

Answer 6

The coenzymes aren’t available for dehydrogenation

Question 7

What process from aerobic respiration is unaffected in anaerobic respiration & still occurs?

Answer 7

Glycolysis, as there are other ways for it to happen

Question 8

What do we need for ATP to be produced in anaerobic conditions

Answer 8

For reduced NAD to be re-oxidised
So ATP can be procured by glycolysis
-> the lactate pathway (mammals) & ethanol pathway (fungi & plants) = metabolic pathways for the re-oxidation of reduced NAD: these occur in the cell cytoplasm

Question 9

How does the ethanol pathway allow glycolysis to occur?

Answer 9

Question 10

How does the lactate pathway allow glycolysis to occur?

Answer 10

Question 11

Ethanol Vs lactate fermentation

Answer 11

Question 12

After lactate is produced in fermentation, how can it enter the Krebs cycle

Answer 12

Via the link reaction:
- then it’s oxidised to pyruvate
- then converted to glucose & glycogen, & stored in the liver

Question 13

What is oxygen debt

Answer 13

Extra oxygen is required to oxidise lactate to pyruvate therefore animals breathe dearer & faster during exercise

Question 14

Hydrogen acceptor in mammals vs yeast

Answer 14

Mammals = pyruvate
Yeast = ethanol

Question 15

Why does lactate have to be metabolised & removed

Answer 15

Otherwise pH in muscle cells = lowered
& action of enzymes in glycolysis / muscle contraction is inhibited

Question 16

The yield of anaerobic respiration is 2 ATP,
It’s much lower as…

Answer 16

Question 17

Oxidative vs substrate level phosphorylation

Answer 17