Muscle contraction

Question 1

Steps of muscle contraction in sarcoplasmic reticulum

Answer 1

sarcoplasmic reticulum releases calcium
calcium binds to troponin C, allowing tropomyosin to move, unblocking the binding sites
myosin binds to the newly released binding site releasing ADP, pulling the Z bands towards each other
ATP binds to myosin, releasing actin

Question 2

Slow contracting fibres
Red due to presence of myoglobin
Mainly used for sustained force
Major fuel = triglycerides
High mitochondrial density

Answer 2

Type 1 skeletal fibres

Question 3

Fast contraction
white colour due to absence of myoglobin
Used for sudden movement
major fuel ATP
Low mitochondrial density

Answer 3

Type II fibres

Question 4

Basic unit of muscles that gives skeletal and cardiac muscles their striated appearance. Segment between two adjacent Z-lines

Answer 4

Sarcomere

Question 5

Thin filaments that transmit the forces generated by myosin to the ends of the muscle

Answer 5

actin

Question 6

Releases calcium ion in response to depolarization

Answer 6

sarcoplasmic reticulum

Question 7

Covers the myosin-binding sites on actin

Answer 7

tropomyosin

Question 8

Binds with calcium ions

Answer 8

Troponin-C