Question

Which of the following is correct regarding changes in noscle fibre from relaxed to contracted state in the given fyur?? Comacted Two sarcom 1a) The length of the thick and thin myofilaments has changed. b) length of both anisotropic and isotropic band has changed. The myosin cross-bridges move on the surface of actin and the thin and thick myofilaments slide past each other. Length of the sarcomere remains same.

Name: Problem 37, Chapter 20: Objective NCERT at your FINGERTIPS: Biology
Uploaded: 2021-10-28T06:55:50-08:00
Duration: 2 min 55 s
Channel: Qudsiya Anis

   Which of the following is correct regarding changes in noscle fibre from relaxed to contracted state in the given fyur??
Comacted
Two sarcom
1a) The length of the thick and thin myofilaments has changed.
b) length of both anisotropic and isotropic band has changed. The myosin cross-bridges move on the surface of actin and the thin and thick myofilaments slide past each other.
Length of the sarcomere remains same.

Objective NCERT at your FINGERTIPS: Biology

NCERT 11th Edition

Chapter 20, Problem 37

Instant Answer

Solved by Expert Qudsiya Anis

10/28/2021

Step 1

The first statement says that the length of the thick and thin myofilaments has changed. This is incorrect because during muscle contraction, the thick and thin myofilaments slide past each other, but their length does not change. Show more…

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Which of the following is correct regarding changes in noscle fibre from relaxed to contracted state in the given fyur?? Comacted Two sarcom 1a) The length of the thick and thin myofilaments has changed. b) length of both anisotropic and isotropic band has changed. The myosin cross-bridges move on the surface of actin and the thin and thick myofilaments slide past each other. Length of the sarcomere remains same.

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Key Concepts

Sliding Filament Theory

The sliding filament theory describes how muscle contraction occurs when the actin (thin) filaments slide over the myosin (thick) filaments. This process is driven by the cyclic attachment and movement of myosin cross-bridges along actin, and it explains that while the filaments themselves remain constant in length, their sliding results in the shortening of the overall muscle fiber.

Sarcomere Structure and Band Changes

The sarcomere is the basic contractile unit of a muscle fiber, defined by distinct regions such as the A band and I band. During contraction, the thin filaments slide over the thick filaments, leading to a decrease in the length of the I band and the overall sarcomere, while the A band remains largely unchanged. This understanding is fundamental in differentiating changes in band lengths from the actual lengths of the filaments during muscle contraction.

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