Biochemistry Of Muscle Contraction

Question 1

Describe redox reactions :oxidation and reduction

Answer 1

When a compound loses h it is oxidised

When a compound gains h it is reduced

Question 2

How do we move? : the muscle cell

Answer 2

1.the myocyte is extremely specialised
2.unlike other cells it is multi nucleated due to fusion of myo blasts during development

Question 3

How do contractile proteins constitute the sarcomere

Answer 3

1.thick and thin filaments overlap are composed of contractile proteins
2.thick -myosin
3.think- actin, tropomyosin and tropomonin

Question 4

Describe the structure of myosin

Answer 4

1.very large and abundant in muscle
2.consists of 2 large heavy chains and 4 small light chains
3.light meromyosin forms filaments spontaneously
4.heavy meromyosin forms cross bridges and s1 subfragment hydrolyses atp and binds to actin

Question 5

Describe actin

Answer 5

1.Main component of thin filaments and exists as G actin and F actin
2.

Question 6

Describe myosin isoforms and fibre type

Answer 6

1.genes encode proteins but variations in proteins can arise from one gene via rna editing
2.these variants are referred to as isoforms
3.myosin displays multiple isoforms that influences muscles and exercise performance

Question 7

How does calcium control muscle activity

Answer 7

It controls muscle contraction by permitting binding of myosin to f actin via tropomyosin and tropomonin

Question 8

How does the nervous system stimulate muscle

Answer 8

1.signals for neurons to muscles are carried out chemically in motor units.
2.as the motor neuron approaches muscle, it splits into thousands of branches ending at the neuromuscular junction