5.6 Anaerobic respiration

Question 1

(lactate) in lactate fermentation pyruvate is converted to what?

Answer 1

lactate

Question 2

(lactate) no O2 means that the electron chain backs up, why?

Answer 2

no O2 to act as the final electron acceptor

Question 3

(lactate) if the electron chain backs up what happens to hydrogen?

Answer 3

it stops dissociating from reduced NAD

Question 4

(lactate) because hydrogen stops dissociating there are no free coenzymes to accept hydrogens, so what other processes stop?

Answer 4

oxidative decarboxylation of pyruvate

krebs cycle

Question 5

(lactate) glycolysis would stop if it weren’t for what?

Answer 5

lactate fermentation

Question 6

(lactate) in what does lactate fermentation occur?

Answer 6

mammals and bacteria

Question 7

(lactate) 1. in mammals pyruvate can act as what?

Answer 7

the final electron acceptor taking the hydrogen from reduced NAD

Question 8

(lactate) 1. what enzyme catalyses pyruvate taking the hydrogen from reduced NAD?

Answer 8

Lactate dehydrogenase

Question 9

(lactate) 2. Pyruvate is converted to what? and what is regenerated?

Answer 9

lactate

NAD

Question 10

(lactate) 3. lactic acid is converted back to what in the liver?

Answer 10

glucose

Question 11

(lactate) 3. lactic acids conversion to glucose requires what and what does this create?

Answer 11

O2

O2 debt which causes heavy breathing

Question 12

(lactate) 4. lactic acid is removed from where?

Answer 12

the bloodstream

Question 13

(lactate) 4. why is lactic acid removed?

Answer 13

to prevent a drop in pH

Question 14

(alcohol) where does alcoholic fermentation occur?

Answer 14

in yeast and plant cells

Question 15

(lactate) is lactate fermentation reversible?

Answer 15

yes

Question 16

(alcohol) 1. is alcohol fermentation reversible?

Answer 16

no

Question 17

(alcohol) 2. Pyruvate is first converted to what?

Answer 17

ethanal

Question 18

(alcohol) 2. pyruvates conversion to ethanal is catalysed by what?

Answer 18

pyruvate decarboxylase

Question 19

(alcohol) 3. ethanal can accept a hydrogen from what?

Answer 19

reduced NAD

Question 20

(alcohol) 3. when ethanal accepts a hydrogen what does it become?

Answer 20

ethanol

Question 21

(alcohol) 4. regenerated NAD can do what? allowing what to continue?

Answer 21

continue as a coenzyme allowing glycolysis to continue

Question 22

(alcohol) 4. ethanol is what?

Answer 22

toxic to yeast

Question 23

(investigation respiration in yeast) why would the flask be sealed?

Answer 23

to ensure anaerobic conditions

Question 24

(investigation respiration in yeast) glucose and yeast placed in conical flask, what does glucose act as?

Answer 24

respiratory substrate

Question 25

(investigation respiration in yeast) a stained water drop is added to the capillary tube what is it used to calculate?

Answer 25

its movement & diameter of tube is used to calculate the increased vol of gas, and rate of respiration

Question 26

(investigation respiration in yeast) why would the rate of respiration eventually plateau?

Answer 26

no more glucose left
yeast killed (ethanol is toxic)