MS Sliding Filiment Theory

Question 1

Define actin

Answer 1

The filament which has binding site for myosin head

Question 2

Define myosin

Answer 2

Thick filament with a head that binds to actin

Question 3

Define tropomyosin

Answer 3

A fibre that is moved in the presence of calcium ions

Question 4

Define myofibrils

Answer 4

long muscle fibres made of many sarcomeres

Question 5

Define sacromere

Answer 5

The part of the muscle that changes shape

Question 6

Define troponin

Answer 6

A protein that causes the movement of tropomyosin which uncovers the binding site on actin

Question 7

Define sarcoplasmic reticulum

Answer 7

A network of smooth ER that sits around the muscle containing sarcoplasm

Question 8

Define ATP (adenosine triphosphate)

Answer 8

Energy source for detaching/ repositioning the myosin head

Question 9

Define ADP (adenosine diphosphate)

Answer 9

Bound to the myosin head

Question 10

What does the sliding filament theory state

Answer 10

That the two proteins - actin and myosin - slide past each other inward when the muscle contracts which shortens the muscle

Question 11

What is sacromeres

Answer 11

The ‘stripes’ on cardiac and skeletal muscle, each sacromere contains two proteins

Question 12

Describe what the protein actin is

Answer 12

Thin fibres with a tropomyosin fibre wrapped around them and another protein called toponin at regular intervals

Question 13

Describe what the protein myosin is

Answer 13

Thick fibres with globular heads that move

Question 14

Describe the structure of a muscle fibre

Answer 14

Made up of a large number of myofibrils which are wrapped in smooth ER membrane - the sarcoplasmic reticulum