AM1 - Sliding Filament Theory

What starts a muscle contraction?

• Release of Calcium Ions

• Attachment of Myosin-Heads

• An Action Potential

• Release of ADP

True or False: Calcium Ions bind to Troponin which causes tropomyosin to move, exposing the binding sites on actin.

• True

• False

___are the thin filaments in a sarcomere.

• troponin

• tropomyosin

• actin

• myosin

___are thick filaments in a sarcomere.

• actin

• myosin

• troponin

• tropomyosin

______ are proteins that cover the myosin binding site on the actin.

• troponin-tropomyosin

• sarcomere

• sarcolemma

• sarcoplasmic reticulum

___forms a crossbridge with actin.

• actin

• myosin

• calcium

• ATP

___slides inward during muscle contraction.

• actin

• myosin

Contractile unit of a muscle.

• sarcomere

• motor unit

• fascicle

• myofibril

What is the structure that stores the Calcium in the muscle cell.

• Sarcoplasm

• Sarcolemma

• Myoglobin

• Sarcoplasmic Reticulum

What happens immediately after the action potential?

• Calcium is released from the sarcoplasmic reticulum

• ADP is released from the sarcoplasmic reticulum

• Phosphate is released from the myosin head

• Myosin heads release from the binding sites on actin