Anatomy of a Myofibril

Question 1

What is the SARCOMERE?

Answer 1

Basic Contractile Unit of Myofibril made of Protein Filaments

Question 2

What is ACTIN?

Answer 2

• Thin Contractile Protein filament
• Contains binding-sites on Troponin and Tropomyosin

Question 3

What is MYOSIN?

Answer 3

• Thick Contractile Protein filament
• With Myosin Heads that bind to form Cross-Bridges

Question 4

Describe the ROLE of TROPONIN

Answer 4

• Allows Ca2+ to bind onto it
• Interacting with Tropomyosin to unblock Myosin-Head binding sites
• Allows for a Cross-Bridge to start Contraction Process

Question 5

Describe the ROLE of TROPOMYOSIN

Answer 5

• Globular Protein that blocks Myosin-head binding sites on Actin
• Prevents Cross-Bridge formation so no Contraction