Grade 12 Biology: Muscle Contraction
This worksheet covers the fundamental principles of muscle contraction at a Grade 12 Biology level, including the sliding filament theory and the role of key proteins.
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Grade 12 Biology: Muscle Contraction
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Read each question carefully and provide detailed answers based on your understanding of muscle contraction.
1. The H-zone of a sarcomere disappears during maximal muscle contraction.
True
False
2. Calcium ions bind directly to myosin heads to initiate muscle contraction.
True
False
1. What is the primary role of ATP in muscle contraction?
To cause the release of calcium ions from the sarcoplasmic reticulum.
To provide energy for the power stroke and detachment of myosin from actin.
To bind to troponin, causing a conformational change.
To activate the motor neuron.
2. Which of the following best describes the 'sliding filament theory'?
Actin and myosin filaments shorten during contraction.
Thick and thin filaments slide past each other, causing the sarcomere to shorten.
Muscle fibers expand in diameter to generate force.
Myosin filaments actively pull on the Z-discs.
1. The functional unit of a muscle fiber is the , which extends from one Z-disc to the next.
2. During muscle contraction, the binding of calcium to causes a conformational change that moves away from the active sites on actin.
1. Briefly explain the role of the sarcoplasmic reticulum and transverse tubules in muscle excitation-contraction coupling.
2. Referring to the image above, identify two key structures involved in muscle contraction and describe their function.