Anaerobic respiration

Question 1

Describe what happens in the absence of oxygen

Answer 1

-Oxygen missing, can’t be final electron acceptor in oxidative phosphorylation. ETC ceases
-Chemiosmosis stops as a result, proton gradient reduces
-NADH and FADH can’t unload H+, therefore NAD and FAD not regenerated
-Krebs and link cycle stops as they are dependent on NAD and FAD
-Glycolysis can still take place, but less NAD produced.

Question 2

Name the two types of fermentation

Answer 2

Ethanol fermentation- yeast and plants
Lactate fermentation- mammals

Question 3

Where does the fermentation occur?

Answer 3

Cytoplasm

Question 4

Describe ethanol fermentation

Answer 4

Pyruvate—> Ethanol +CO2
-Decarboxylated by pyruvate decarboxylase
-Reduced by 2NADH, making 2NAD too
-not reversible

Question 5

Describe lactate fermentation

Answer 5

Pyruvate—->lactate
-Reduced by 2NADH, making 2NAD too
-lactate carried from muscle tissue to liver by the blood
-converted back to glucose, but needs oxygen to do so
-creates oxygen debt

Question 6

Define Obligate anaerobes

Answer 6

-can only synthesise in presence of oxygen
-die when too much oxygen, so live in low oxygen

Question 7

Define Facultative anaerobes

Answer 7

-Can live with or without oxygen
-can do both anaerobic and aerobic respiration

Question 8

How is the rate of O2 and CO2 exchange (respiration) measured for animals?

Answer 8

-Respirometer
-pressure changes measured by distance moved by fluid in manometer- shows CO2 produced
-change in CO2 ppm/ change in time= rate of respiration