4.4 Anaerobic respiration

Question 1

Why glycolysis only source of ATP?

Describe regeneration of NAD from NADH (3)

Answer 1

No O2

NADH releases H
Pyruvate accepts H
NAD can take up H in glycolysis

Question 2

Plants - ethanol and CO2:

equation?
regenerated NAD?
Ethanol?

Answer 2

Pyruvate + NADH —> ethanol + CO2 + NAD
Regenerated NAD - takes up H in glycolysis
Ethanol - used in brewing industry

Question 3

Animals - lactate:

```
equation?
Occurs in?
2
Regenerated NAD?
Lactate?
(2)
~~~

Answer 3

Pyruvate + NADH —> lactate + NAD

Muscles as result of strenuous exercise
Oxygen used more rapidly than supplied
Oxygen debt occurs

Regenerated NAD - takes up H in glycolysis

Lactate - converted back to pyruvate when sufficient oxygen
Used in aerobic respiration/converted to glycogen
If not, causes cramp/muscle fatigue

Question 4

Energy yields:

In plants?
In animals?
ATP?

Answer 4

Ethanol and CO2 (in plants)
Lactate (in animals)
Little ATP (no link, Krebs, ETC - no substrate-level phosphorylation/oxidative phosphorylation)

Question 5

Define oxidative phosphorylation

Define substrate level phosphorylation

Answer 5

The indirect linking of ADP and Pi to produce ATP, using H atoms carried by coenzymes (krebs, etc)

The direct linking of ADP and Pi to produce ATP (glycolysis)