Sliding Filament

What two proteins are needed for muscle contraction in the human body?

• tropin & tropymosin

• actin $ Calcium

• actin & myosin

• ATP & Calcium

Where are the actin and myosin filaments in every one of your muscle fibers located?

• endomysium

• perimysium

• Epimysium

• Sarcomere

Name what this is in your mucles?

• sarcomere

• sarcoplasmic reticulum

• mitochondria

• tublules

Name the structure labeled #5 in diagram.

• endomysium

• epimysium

• perimysium

• myofibril

Explain the sliding filament theory of muscle contraction.

• Actin filaments slide over myosin filaments, shortening the sarcomere and causing muscle contraction.

• Myosin filaments slide over actin filaments, lengthening the sarcomere and causing muscle relaxation.

• Actin and myosin filaments remain stationary, and the sarcomere changes length.

• Myosin filaments dissolve, allowing actin filaments to contract.

Tags

DOK Level 2: Skill/Concept

Which events occur during stage 2 of the Sliding Filament Theory? (Select 2)

• Calcium exposes the active site on the actin for the myosin to attach

• Myosin attaches to actin and a cross-bridge forms

• New ATP attaches to myosin head causing the myosin head to release from the actin

• Myosin head reloads for next stroke

Which events occur during stage 1 of the Sliding Filament Theory? (Select 2)

• Calcium ions are released from the sarcoplasmic reticulum

• Nerve impulse reaches the muscle cell and starts the contraction cycle

• ATP splits into ADP & Pi

• New ATP attaches to myosin head causing the myosin head to release from the actin

What is the role of ATP in the sliding filament theory?

• ATP binds to actin, causing it to slide over myosin.

• ATP provides the energy for myosin heads to detach from actin and reattach for another cycle.

• ATP is not involved in the sliding filament theory.

• ATP binds to calcium ions, facilitating muscle contraction.

Tags

DOK Level 2: Skill/Concept

Which events occur during stage 3 of the Sliding Filament Theory? (Select 2)

• Actin is pulled toward the M-line

• Myosin attaches to actin and a cross-bridge forms

• New ATP attaches to myosin head causing the myosin head to release from the actin

• ADP & Pi are released

Which of the following statements regarding the sliding filament model is false?

• The sarcomere shortens.

• The A band remains constant in length.

• Actin and myosin do not shorten during contraction.

• Both actin and myosin myofilaments shorten during contraction.