Define sliding filament theory of muscle | Class 11 Biology Chapter Locomotion and Movement, Locomotion and Movement NCERT Solutions

Welcome to the NCERT Solutions for Class 11 Biology - Chapter Locomotion and Movement. This page offers a step-by-step solution to the specific question from Exercise 1, Question 2: . With detailed answers and explanations for each chapter, students can strengthen their understanding and prepare confidently for exams. Ideal for CBSE and other board students, this resource will simplify your study experience.

Question 2:

Define sliding filament theory of muscle contraction.

Answer:

The sliding filament theory explains the process of muscle contraction during which the thin filaments slide over the thick filaments, which shortens the myofibril.

Each muscle fibre has an alternate light and dark band, which contains a special contractile protein, called actin and myosin respectively. Actin is a thin contractile protein present in the light band and is known as the I-band, whereas myosin is a thick contractile protein present in the dark band and is known as the A-band. There is an elastic fibre called z line that bisects each I-band. The thin filament is firmly anchored to the z line. The central part of the thick filament that is not overlapped by the thin filament is known as the H-zone.

During muscle contraction, the myosin heads or cross bridges come in close contact with the thin filaments. As a result, the thin filaments are pulled towards the middle of the sarcomere. The Z line attached to the actin filaments is also pulled leading to the shortening of the sarcomere. Hence, the length of the A- band remains constant as its original length and the I-band shortens and the H-zone disappears.

Relaxed Sarcomere

 


Study Tips for Answering NCERT Questions:

NCERT questions are designed to test your understanding of the concepts and theories discussed in the chapter. Here are some tips to help you answer NCERT questions effectively:

  • Read the question carefully and focus on the core concept being asked.
  • Reference examples and data from the chapter when answering questions about Locomotion and Movement.
  • Review previous year question papers to get an idea of how such questions may be framed in exams.
  • Practice answering questions within the time limit to improve your speed and accuracy.
  • Discuss your answers with your teachers or peers to get feedback and improve your understanding.

Latest Blog Posts

Stay updated with our latest educational content and study tips

Understanding Procrastination and Why Students Delay Studying | How To Fix It

One of the challenging things students face nowadays is procrastination. It hinders productivity, making it difficult for students to score well. We often associate procrastination as just being lazy. But there’s more to it. Various studies have shown that procrastination stems from negative feelings such as stress and anxiety. Oftentimes, when we start, we think […]

Read More

Effective Tips to Avoid Nervous Breakdown during CBSE Board Exam

The CBSE Board Exam is a crucial milestone for millions of students across India. The Central Board of Secondary Education is famous for its imparting quality education and knowledge which reaches out to a large share of students. Also, it is important to know that, the CBSE board takes a slight unconventional route, since it […]

Read More

HSSC CET Haryana 2025: Admit Card, Exam Dates, Fees, and More

Haryana government issued a notification on 31st December 2024 through its Gazette notification No. 42/119/2019-5HR-II for CET Haryana 2024. The Common Eligibility Test (CET) for Haryana is a significant opportunity for candidates seeking government jobs in Group C and Group D posts. Below is a comprehensive summary of the key information you need to know […]

Read More

Why Sleep is Crucial for Memory Retention and Learning?

Sacrificing your sleep to study more is doing more damage than you think. While it may seem like utilizing every hour of the day for study leads to better outcomes, the reality is quite the opposite. Lack of proper rest can negatively impact your brain, especially when it comes to sleep and memory retention. You’ll […]

Read More

Add Comment

Welcome to the NCERT Solutions for Class 11 Biology - Chapter . This page offers a step-by-step solution to the specific question from Excercise 1 , Question 2: Define sliding filament theory of muscle contraction.....