HAP #25 - Sliding Filament Theory and ATP

The contractile unit of a muscle:

• sarcomere

• motor unit

• fascicle

• myofibril

The energy needed to perform a muscle contraction comes directly from

• ATP

• Oxygen

• Glucose

• Calcium

The neurotransmitter stored in the axon terminal identified as #3

• Calcium Ion (Ca²⁺)

• Protein Channel

• Acetylcholine

• Synaptic Cleft

Do the lengths of the thick and thin filaments change during contraction?

• Yes

• No

What state is the sarcomere in #1

• Relaxed
• Contracting
• Fully Contracted
• None of the above

What state is the sarcomere in #2

• Relaxed
• Contracting
• Fully Contracted
• None of the above

Calcium:

• causes ATP binding to actin

• increases the action potential along the sarcolemma

• binds to proteins on myosin

• triggers the binding of myosin to actin

What is a crossbridge?

• Where myosin binds to actin

• Where the calcium crosses into the cytoplasm

• Where calcium binds with troponin

• None of the answers are correct.

Calcium binds to ___of the troponin-tropomyosin complex.

• troponin

• tropomyosin

• actin

• myosin

Place the following events in sequence:

A) Your arm moves

B) An impulse travels along a nerve

C) You decide you want to move your arm.

• A B C

• C B A

• C A B

• A C B