Courses
Courses for Kids
Free study material
Offline Centres
More
Store Icon
Store

NCERT Solutions for Class 11 Biology Chapter 20 - Locomotion And Movement

ffImage
Last updated date: 22nd Jul 2024
Total views: 798.6k
Views today: 11.98k

NCERT Solutions for Class 11 Biology Chapter 20 - Locomotion and Movement

CBSE students who are preparing for their 11th year’s final examinations will often find difficulties in one of the chapters of Biology named Locomotion and Movement. Vedantu is here with the NCERT Solutions for Class 11 Biology Chapter 20 Locomotion and Movement which will provide the students with accurate and unambiguous answers for every textbook question. It comes with an overview of the chapter and the solutions make the students understand the concepts in a better way. 


Class:

NCERT Solutions for Class 11

Subject:

Class 11 Biology

Chapter Name:

Chapter 20 - Locomotion and Movement

Content-Type:

Text, Videos, Images and PDF Format

Academic Year:

2024-25

Medium:

English and Hindi

Available Materials:

Chapter Wise

Other Materials

  • Important Questions

  • Revision Notes



Note: Calculate your potential NEET rank based on marks with our NEET Rank Predictor by Marks!


By referring to the CBSE Class 11 Biology Chapter 20 NCERT Solutions, students will get a clear idea about the correct writing pattern of the answers from examinations’ point of view. Learn to master the art of excellent formation of answers and secure high scores in your examinations. 


Locomotion and Movement Chapter at a Glance - Class 11 NCERT Solutions


Locomotion and Movement


Locomotion and Movement

Competitive Exams after 12th Science
tp-imag
bottom-arrow
tp-imag
bottom-arrow
tp-imag
bottom-arrow
tp-imag
bottom-arrow
tp-imag
bottom-arrow
tp-imag
bottom-arrow

Access NCERT Solutions for Class 11 Biology Chapter 20 – Locomotion and Movement

1. Draw the diagram of a sarcomere of skeletal muscle showing different regions. 

Ans: The diagrammatic representation of a sarcomere is as follows:


Sarcomere


2. Define the sliding filament theory of muscle contraction. 

Ans: The sliding filament theory describes the process of muscle contraction in which the thick filaments (myosin) of muscle fibres slide past the thin filaments (actin), resulting in the shortening of the myofibril. Each muscle fibre consists of alternate light and dark bands. They contain a unique contractile protein called actin and myosin respectively. Myosin is a thick contractile protein found in the dark band and is known as the A-band or Anisotropic band. Actin is a thin contractile protein found in the light band and is known as the I-band or Isotropic band.  Each I-band is bisected by an elastic fibre known as the Z line. The thin filament (actin) is firmly attached to the Z line. The H-zone is the central portion of the thick filament (myosin) that is not overlapped by the thin filament. Sarcomere, the functional unit of contraction, is the portion of the myofibril between two successive Z lines.

During muscle contraction, the myosin heads come into close contact with the thin filaments. As a result, the thin filaments are pulled towards the centre of the sarcomere as well as the Z line attached to the actin filaments is also pulled, causing shortening of the sarcomere. The length of the A-band or anisotropic band remains constant as its original length whereas the I-band or isotropic band shortens and the H-zone disappears.


Muscle Contraction


3. Describe the important steps in muscle contraction.

Ans: During skeletal muscle contraction, the thick filament slides past the thin filament (actin) via repeated binding, releasing myosin along the filament. This entire process takes place in sequential order. 

  1. Step 1: Muscle contraction is initiated by a signal that is sent by a CNS (Central nervous system) through a motor neuron. A neuromuscular junction or motor-end plate is a junction between a motor neuron and the sarcolemma of the muscle fibre. When a signal reaches the neuromuscular junctions, Acetylcholine (a neurotransmitter) is released which results in the generation of an action potential in the sarcolemma. 

  2. Step 2: This spreads through the muscle fibres, resulting in the release of calcium ions from the sarcoplasmic reticulum into the sarcoplasm.

  3. Step 3: The increased calcium ions $\text{(C}{{\text{a}}^{\text{2+}}}\text{)}$ in the sarcoplasm leads to the activation of actin sites. Calcium ions $\text{(C}{{\text{a}}^{\text{2+}}}\text{)}$ bind with the subunit of troponin on actin filaments and thus remove the masking of active sites for myosin. Hence, active sites on actin are exposed and this allows myosin heads to attach to this site. 

  4. Step 4: The myosin head now attaches to the exposed site of actin to form a cross-bridge by utilizing energy from ATP hydrolysis. The actin filaments are pulled towards the centre of the A-band. The Z line attached to the actin filaments is also pulled, causing shortening of the sarcomere, i.e., the contraction of the muscle occurs. It is clear from the above steps, that during contraction, the length of the A-band or anisotropic band remains constant as its original length whereas the I-band or isotropic band gets reduced.

  5. Step 5: After muscle contraction, the myosin head goes back to its relaxed state, releasing ADP and inorganic phosphate (Pi). A new ATP molecule binds and detaches myosin, thus the cross-bridges are broken.

  6. Step 6: This process of formation and breaking down is repeated causing further sliding. This process continues until the calcium ions are pumped back to the sarcoplasmic cisternae. Hence, the calcium ions concentration decreases. This results in masking the actin filaments and leading to muscle relaxation.


4. Write true or false. If false, change the statement so that it is true. 

  1. Actin is present in the thin filament.

  2. H-zone of striated muscle fibre represents both thick and thin filaments.

  3. The human skeleton has 206 bones. 

  4. There are 11 pairs of ribs in man.

  5. The sternum is present on the ventral side of the body.

Ans: 

  1. True

  2. False. The H-zone of striated muscle fibre represents only a thick filament.

  3. True

  4. False. There are 12 pairs of ribs in a man.

  5. True


5. Write the difference between: 

  1. Actin and Myosin 

  2. Red and White muscles

  3. Pectoral and Pelvic girdle

Ans:

  1. The difference between Actin and Myosin are: -


Actin

Myosin


Actin is a thin contractile protein.

Myosin is a thick contractile protein.


It is present in the light bands and is called an I-band or isotropic band.

It is present in the dark bands and is called an A-band or anisotropic band.


It has a smooth surface.

It has a rough surface.


It does not form cross-bridges.

It forms cross-bridges. 


It consists of troponin and tropomyosin.

It consists of meromyosin (myosin monomer).


  1. The difference between red and white muscle fibres are: -


Red Muscle Fibre

White Muscle Fibre


Red muscle fibres are thinner and smaller than white muscle fibres.

White muscle fibres are thicker and larger than red muscle fibres. 


They are red in colour because they possess large amounts of myoglobin. 

They are white in colour because they possess small amounts of myoglobin. 


They have mitochondria in large numbers. 

They have a comparatively smaller number of mitochondria. 


They carry out a slow rate of contractions for a long period. 

They carry out a fast rate of contraction for a short duration. 


They provide energy by performing aerobic respiration.

They provide energy by performing anaerobic respiration


  1. The difference between pectoral and pelvic girdles are: -


Pectoral Girdle

Pelvic Girdle


The pectoral girdle is situated in the shoulder (pectoral region).

The pelvic girdle is situated in the hip (pelvic region).


It is composed of two bones: - Clavicle or collar bones and scapula or shoulder bone.

It is composed of three bones: - the upper ileum, inner pubic, and ischium.


It helps in the articulation of upper limbs.

It helps in the articulation of lower limbs.


It performs functions like lifting, holding etc.

It performs functions like walking, standing, jumping, running etc.


6. Match Column I with Column II:


Column I


Column II


Smooth Muscle


Myoglobin


Tropomyosin


Thin Filament


Red muscle


Sutures


Skull


Involuntary


Ans: 


Column I


Column II


Smooth Muscle


Involuntary


Tropomyosin


Thin filament


Red muscle


Myoglobin


Skull


Sutures


7. What are the different types of movements exhibited by the cells of the human body?

Ans: Movement is a characteristic property of all living organisms. Cells in the human body exhibit various types of movement, which are as follows:

  1. Amoeboid Movement: This type of movement is exhibited by some specialised cells like leucocytes (White blood cells) and macrophages (immune cells) present in the blood. These blood cells move from the circulatory system to the injury site during tissue damage to initiate an immune response.

  2. Ciliary Movement: This type of movement is exhibited by reproductive cells such as sperms and ova. Ciliary movement facilitates the passage of the ova through the fallopian tube towards the uterus.

  3. Muscular Movement: This type of movement is exhibited by muscle cells which are caused by the contraction of the myofibril of the muscle cells.


8. How do you distinguish between a skeletal muscle and a cardiac muscle?

Ans: The difference between a skeletal muscle and a cardiac muscle are:


Skeletal Muscle 

Cardiac Muscle


Skeletal muscles are attached to the bones and skins.

The heart is the only organ with cardiac muscles.


They are voluntary muscles as their activities are under the voluntary control of the nervous system.

They are involuntary muscles as their activities are not directly controlled by the nervous system. They are controlled by the central nervous system, endocrine system and different chemicals.


The cells of the skeletal muscles are straight, cylindrical, non-branched and multinucleated.

The cells of the cardiac muscles are cylindrical, branched and uni-nucleated.


They do not have intercalated discs.

Intercalated discs connect the cells and aid in the coordination or synchronization of the heartbeat.


They have a high energy requirement.

They have an intermediate energy requirement.


They contract rapidly and are fatigued easily in a short period of time.

They contract rapidly but do not fatigue easily.


They help in movement and locomotion.

They help in the contraction and relaxation of the heart.


     

Skeletal Muscle


Cardiac Muscle


9. Name the type of joint between the following: 

  1. Atlas/axis

  2. carpal/metacarpal of the thumb

  3. between phalanges 

  4. femur/acetabulum 

  5. between cranial bones 

  6. between pubic bones in the pelvic girdle

Ans.

  1. Atlas/axis: Pivot joint is present in between atlas and axis.

  2. carpal/metacarpal of thumb: The saddle joint is located between the carpal and metacarpal of the thumb.

  3. between phalanges: Hinge joint is present in between phalanges.

  4. femur/acetabulum: Ball and socket joint is present in between the head of femur and acetabulum.

  5. between cranial bones: Fibrous joint is present in between cranial bones.

  6. between pubic bones in the pelvic girdle: Ball and socket joint is present in between pubic bones in the pelvic girdle.


10. Fill in the blank spaces: 

  1. All mammals (except a few) have __________ cervical vertebrae. 

  2. The number of phalanges in each limb of a human is __________. 

  3. Thin filament of myofibril contains 2 ‘F’ actins and two other proteins namely __________ and __________. 

  4. In a muscle fibre $\text{(C}{{\text{a}}^{\text{2+}}}\text{)}$ is stored in __________.

  5. __________ and __________ pairs of ribs are called floating ribs. 

  6. The human cranium is made of __________ bones.

Ans.

  1. All mammals (except a few) have seven cervical vertebrae. 

  2. The number of phalanges in each limb of a human is 14

  3. The thin filament of myofibril contains 2 ‘F’ actins and two other proteins namely troponin and myosin.

  4. In a muscle fibre $\text{(C}{{\text{a}}^{\text{2+}}}\text{)}$ is stored in the sarcoplasmic reticulum.

  5. $\text{1}{{\text{1}}^{\text{th}}}$ and $\text{1}{{\text{2}}^{\text{th}}}$ pairs of ribs are called floating ribs. 

  6. The human cranium is made of eight bones.


NCERT Solutions for Class 11 Biology Chapter 20 - Locomotion and Movement

The PDF for Class 11 bio ch 20 NCERT Solutions is now available on the official site of Vedantu. Download the PDF and get access to all the CBSE Class 11 Biology Chapter 20 NCERT Solutions for free. The PDF serves as an outstanding source for all the students who are worried about scoring well in that particular chapter. All the answers are written by expert biologists who have done a great job in using simple sentences for a complex subject like Biology. By downloading the PDF, students won’t have to waste their time looking for answers on various sites. All the questions and answers are gathered together inside the PDF to make it convenient for the students.


NCERT Solutions of Locomotion and Movement Class 11

Chapter 20 of the NCERT Biology book Class 11 is Locomotion and Movement, which is one of the chapters of Unit 5, Human Physiology. The chapter deals with various forms of locomotion that take place in the human body as well as inside unicellular organisms. Various types of muscle movements, joint movements and the skeleton structure of the body are some of the important topics covered in this chapter. The chapter also makes the students aware of the disorders of skeleton and muscle system of the body. Use of colourful diagrams attract the interest of students and make learning more fun. 

Information regarding disorders like arthritis is also given in this chapter. Concepts related to voluntary and involuntary action of muscles, detailed explanations about various functions of bones and joints are also provided in this chapter. Class 11 bio ch 20 NCERT Solutions will provide accurate and to the point answers concerning all these topics.


NCERT Solutions of Chapter 20 Biology Class 11- Marks Weightage

Overall the whole 5th unit consists of seven chapters. Locomotion and Movements is the 20th chapter of the CBSE Biology syllabus of Class 11. The 5th unit is one of the most important units as it carries 18 marks for final examinations. Every chapter that comes under this unit has a great potential to score maximum marks. Moreover, considering the 20 percentage weightage allotted to the 5 units for NEET examinations, students must start preparing from the NCERT Solutions for Class 11 Biology Locomotion and Movement beforehand.


Benefits of NCERT Solutions for Class 11 Biology Locomotion and Movement

The PDF provided by Vedantu has covered all the ch 20 bio Class 11 NCERT Solutions to help the students secure outstanding results in their examinations. The solutions will benefit the students to a very great extent because of the following points:

  • All the answers to the textbook questions are available in simple language.

  • The precise summary of the chapter helps the students review every topic before the examinations.

  • Experienced Biology teachers are the ones providing all the accurate answers with the help of various examples. 

  • The PDF can be accessed online as well as offline after downloading. 

  • Diagramatic explanation helps the students understand the body structure easily.

  • By referring to the Locomotion and Movement Class 11 NCERT Solutions, students are guaranteed to score excellent marks and achieve the highest scores in their examinations.

FAQs on NCERT Solutions for Class 11 Biology Chapter 20 - Locomotion And Movement

1. Write about the Different Types of Movement Exhibited By the Cells of the Human Body.

One of the essential characteristics of the human body is the movements. Every second of the day, we make different kinds of movements. Three different types of movements performed by the cells of the human body are as follows;

  • Amoeboid Movement - Leukocytes present in our body are responsible for making amoeboid movement. In case of damaged tissues, these blood cells move from the circulatory system towards the injury to initiate the immune response.

  • Ciliary Movement - this movement is shown by the reproductive cells like sperms and ova.

  • Muscular Movement - muscular movements are performed by the muscle cells.

2. Write the Differences Between Red and White Muscle Fibre.

  • Compared to the white muscle fibre, red muscle fibre is smaller and thin.

  • Red muscle fibre contains a considerable amount of myoglobin which is responsible for its red colour. On the other hand, the less amount of myoglobin present inside the white muscle fibre is responsible for its white colour.

  • As compared to the white muscle fibre, more mitochondria can be found in red muscle fibre.

  • Red muscle fibre provides energy by performing aerobic respiration, whereas white muscle fibre performs anaerobic respiration to produce energy.

3. What are the topics covered in Class 11 Biology Chapter 20?

The topics covered in class 11 Biology Chapter 20 are:

  • Types of movements

  • Muscles

  • Skeletal system 

  • Joints 

  • Disorder of skeletal and muscular systems.

It is important for the students to be thorough with all these topics in order to be able to answer all the questions asked from this particular chapter. In order to attain this, they can refer to the NCERT solutions by Vedantu and practice all the exercises that this chapter offers. Regular practice and revision are very important to be able to remember the concepts.

4. What are the different types of muscles?

There are three different types of muscles. These are,


Skeletal Muscles

They are closely linked with the skeletal attributes of the human body. When viewed under the microscope, their appearance is stripped, therefore they are also referred to as the striated muscles. They are also known as voluntary muscles, as their activities are usually under the control of the nervous system. Their primary function involves locomotory actions and the changes of the body postures.


Visceral Muscles

They are seen present in the inner walls of the hollow visceral organs of the human body, for example, the alimentary canal, reproductive tracts, etc. They have a smooth appearance, as opposed to skeletal muscles. Therefore, they are termed smooth muscles or nonstriated muscles. They are also known as involuntary muscles.


Cardiac Muscles

These are the muscles present in the heart. They are striated in appearance and involuntary in function.

5. What are the disorders associated with the muscular and skeletal systems?

Some disorders associated with the muscular and skeletal systems are as follows,


Myasthenia Gravis

This is an autoimmune disease that affects the neuromuscular junction. This may lead to fatigue, weakening, and ultimately to the paralysis of skeletal muscle.


Arthritis 

This results in the inflammation of joints.


Gout

This leads to the inflammation of joints as a result of the accumulation of uric acid crystals.


Muscular Dystrophy

This is the progressive degeneration of skeletal muscles. Its main reason involves a genetic disorder. 


To know more about them, visit Vedantu.

6. Are NCERT Solutions available for class 11 Biology Chapter 20?

Yes, the NCERT solutions can be easily accessed for Class 11 Biology Chapter 20. Students can download these solutions from the website of Vedantu. These solutions will help the students to attain a better grasp of the topics that the chapter offers. The various exercises are devised in order to prepare the students for the exams. These solutions are planned by the experts to meet the needs of the students. Every question has a detailed answer that helps the students to retain what they have studied. 

7. How to prepare for class 11 Biology Chapter 20?

The student needs to read the chapter thoroughly first. While reading they should mark all the important words and definitions. This will help them to access important points whenever required. Apart from this, it is also important that they make their own revision notes so that they are able to remember what they are studying. For the subject of Biology, it is very important to learn and retain all the important biological names. Therefore, it is important that the student practices all the important names, time and again.