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 3: . 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.
Describe the important steps in muscle contraction.
During skeletal muscle contraction, the thick filament slides over the thin filament by a repeated binding and releases of myosin head along the filament. This whole process occurs in a sequential manner.
Step 1:
Muscle contraction is initiated by signals that travel along the axon and reach the neuromuscular junction or motor end plate. Neuromuscular junction is a junction between a neuron and the sarcolemma of the muscle fibre. As a result, Acetylcholine (a neurotransmitter) is released into the synaptic cleft by generating an action potential in sarcolemma.
Step 2:
The generation of this action potential releases calcium ions from the sarcoplasmic reticulum in the sarcoplasm.
Step 3:
The increased calcium ions in the sarcoplasm leads to the activation of actin sites. Calcium ions bind to the troponin on actin filaments and remove the tropomyosin, wrapped around actin filaments. Hence, active actin sites are exposed and this allows myosin heads to attach to this site.
Step 4:
In this stage, the myosin head attaches to the exposed site of actin and forms cross bridges by utilizing energy from ATP hydrolysis. The actin filaments are pulled. As a result, the H-zone reduces. It is at this stage that the contraction of the muscle occurs.
Step 5:
After muscle contraction, the myosin head pulls the actin filament and releases ADP along with inorganic phosphate. ATP molecules bind and detach myosin and the cross bridges are broken.
Step 6:
This process of formation and breaking down of cross bridges continues until there is a drop in the stimulus.As a result, the concentration of calcium ions decreases, thereby masking the actin filaments and leading to muscle relaxation.
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:
Stay updated with our latest educational content and study tips
Online gaming has rapidly become one of the most popular pastimes among children. Whether it’s multiplayer mobile games , PC adventures or console challenges , kids are spending more time than ever in the virtual world . On the surface, gaming seems entertaining and even educational – improving hand- eye coordination , teamwork and problem […]
Read MoreKids today are surrounded by screens from the moment they wake up . Whether it’s smart classrooms, online lessons or video games with friends technology has quietly become a part of everything they do. It’s amazing how much they can learn, explore and create with just a tap or a click. But it also brings […]
Read MoreThe internet is full of entertaining apps, games and movies for kids of all ages. However not everything online is safe. Hidden among these entertaining platforms are internet frauds that target children with phony gifts, free game currencies or friendly looking people. As a parent, you may believe that scammers only target adults; yet children […]
Read MoreDid you know? The average teenager spends 7 – 8 hours daily on screens . That’s almost like working a full – time job in front of a screen – except kids aren’t earning a paycheck; instead they’re often trading sleep, focus and health for digital time. In today’s world, screens are everywhere – TV, […]
Read MoreWelcome 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 3: Describe the important steps in muscle contraction.....
Comments
its easy to understand