anaerobic respiration

Question 1

what cannot take place in the absence of oxygen and why

Answer 1

as no water can be made which mean that the electrons cannot leave the respiratory chain so no hydrogen can be released from nadh so all nad is in the nadh form

Question 2

why is it a problem if nad is in its reduced form

Answer 2

some of the enzymes required for glycolsis cannot work or those required for krebs cycle

Question 3

how does anaerobic overcome this proble

Answer 3

add another step that regenerates nad allowing glycolysis to continue and generate some atp

Question 4

how does anaerobic respiration take place in plants

Answer 4

the pyruvate accepts an hydrogen released from the nadh to reform nad and loses a co2 forming ethanol

Question 5

how does anaerobic respiration take place in animals

Answer 5

the pyruvate converted to lactic acid by the reduced nadh reducing pyruvate to reform nad for glycolysis

Question 6

when is producing lactate useful

Answer 6

allows energy to be produced even when oxygen levels cannot be met for example running away from a predator

Question 7

what is the reaction like in anaerobic animals

Answer 7

the reaction is reversible so energy remaining in the lactate can be retrieved when oxygen is available and oxidised into pyruvate

Question 8

what happens when oxygen is present with lactate

Answer 8

the lactate is oxidised back into pyruvate and then can enter the krebs cycle and produce more atp

Question 9

what about the reversibility of anaerobic reaction in plants

Answer 9

reaction is irreversible as it form a two carbon compound which means the energy stored by ethanol cannot be retrieved by the cells