🔬 Biology · Locomotion and Movement · NEET

The basic contractile (functional) unit of a striated muscle fibre is the:

Answer: sarcomere.

A sarcomere
B neuron
C nephron
D alveolus

Correct answer: A. sarcomere

Explanation: The sarcomere, between two Z-lines, is the functional unit of muscle contraction.

Structure of a sarcomere showing thick myosin filaments and thin actin filaments with the Z line, M line, A band, I band and H zone labelled

A sarcomere (Z line to Z line): during contraction the I band and H zone shorten as thin filaments slide over thick, while the A band stays the same length. Image: SlothMcCarty, CC BY-SA 3.0, via Wikimedia Commons.

Concept context

Types of movement, muscle contraction, skeletal system, joints, and disorders. Important for Class 11 and NEET.

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The basic contractile (functional) unit of a striated muscle fibre is the:

Concept context

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