Sliding Filament Theory

Describe the role of calcium ions in muscle contraction.

• They bind to troponin, causing a conformational change that allows myosin to bind to actin.

• They provide energy for the contraction process.

• They break down ATP to release energy.

• They transport oxygen to the muscle fibers.

Tags

DOK Level 2: Skill/Concept

Which of the following best describes the power stoke?

• actin's troponin pulls on the myosin filament

• myosin heads pull on binding sites of the actin filament

What state is the sarcomere in

• Relaxed

• Contracting

• Fully Contracted

• None of the above

What state is the sarcomere in #2

• Relaxed

• Contracting

• Fully Contracted

• None of the above

As calcium binds to actin the myosin heads are allowed to bind to the actin forming a cross-bridge and begin to slide over mysoin.

• True

• False

Looking at the figure what molecule will allow the myosin head to detach from actin.

• ADP

• Myosin

• ATP

• Creatine Phosphate

Looking at the figure which one is a fully contracted muscle?

• A

• B

• C

• All are contracted

When ATP binds to the myosin head the myosin head then _____________.

• completes a power stroke

• attaches to actin

• rotates

• detaches from actin

Actin is the ...

• Thick Filament within a Muscle Fibre

• Thin Filament within a Muscle Fibre

• Protein that covers myosin-binding sites

• Molecule that causes muscle contraction

Myosin is the ...

• Thin Filament of a muscle fibre

• Segment of a muscle fibre

• A molecule that changes shape when bound with Calcium Ions

• Thick Filament of a muscle fibre