Sliding Filament Theory of Muscle Contraction

Front

What is the primary function of the sarcoplasmic reticulum in muscle cells?

Back

The sarcoplasmic reticulum stores calcium ions, which are released during muscle contraction.

Front

What role does troponin play in muscle contraction?

Back

Troponin binds calcium ions, causing a conformational change that allows tropomyosin to move away from actin binding sites, enabling muscle contraction.

Front

What happens to the length of the sarcomere during muscle contraction?

Back

The sarcomere shortens as actin filaments slide over myosin filaments.

Front

Which filament slides inward during muscle contraction?

Back

Actin filaments slide inward toward the center of the sarcomere.

Front

What molecule provides the energy necessary for muscle contraction?

Back

ATP (adenosine triphosphate) provides the energy for muscle contraction and relaxation.

Front

What is the role of myosin in muscle contraction?

Back

Myosin heads bind to actin filaments and pull them, causing muscle contraction.

Front

Define the sliding filament theory of muscle contraction.

Back

The sliding filament theory states that muscle contraction occurs when actin filaments slide past myosin filaments, shortening the sarcomere.

Front

What is the function of tropomyosin in muscle contraction?

Back

Tropomyosin blocks the binding sites on actin filaments, preventing contraction until calcium binds to troponin.

Front

How does calcium ion concentration affect muscle contraction?

Back

Increased calcium ion concentration leads to muscle contraction by enabling the interaction between actin and myosin.

Front

What is the significance of the M line in a sarcomere?

Back

The M line is the center of the sarcomere where myosin filaments are anchored.