Anaerobic Respiration in mammalian muscle cells

Question 1

What are the steps of Anaerobic Respiration in mammalian muscle cells?

Answer 1

• In this pathway, reduced NAD transfers its hydrogens to pyruvate to form lactate
• pyruvate is reduced to lactate by enzyme lactate dehydrogenase
• pyruvate is the hydrogen acceptor
• the final product lactate can be further metabolised

Question 2

Why is the reduced NAD re-oxidised?

Answer 2

• So it can be re-used to accept more hydrogen atoms

Question 3

Why is pyruvate the hydrogen acceptor?

Answer 3

• It allows NAD to be regenerated (the pyruvate is reduced)
• requires the ezyme lactate dehyrogenase

Question 4

Does glycolsysis continue ?

Answer 4

• yes, it generates enough ATP to sustain muscle contraction

Question 5

What happens to the lactate ?

Answer 5

• it is carried from the muscle to the liver
• when oxygen is available, it is turned back into glucose - which can enter glycolsysis or can be stored as glycogen
• it can be converted to pyruvate and enter the link reaction of respiration

Question 6

Why is it important that the lactate is removed from the muscles quickly?

Answer 6

• it will reduce the PH of the muscle cells
• inhibit enzymes in the muscle cells
• inhibit muscle contraction (requires enzymes)