NCERT Solutions for Class 11 Biology Chapter 20 Locomotion and Movement

 

NCERT solutions for class 11 biology chapter 20 locomotion and movement: Movement is one of the significant features of all living beings as animals and plants exhibit a wide range of movements. You know that human beings can move their eyelids, limbs, jaws, tongue, etc and some of the movements result in a change of place or location. In the solutions for NCERT class 11 biology chapter 20 locomotion and movement, you will get questions related to such topics like locomotion and movements of our body part. Some voluntary motions like walking, running, climbing, swimming, flying are some forms of locomotory movements. Locomotory structures need not be different from those affecting other types of movements. For example, in Paramoecium, cilia help in the movement of food through cytopharynx and in locomotion as well. The methods of locomotion that are performed by animals vary with their habitats and the demand of the situation which you need to learn in deep as you will get related questions and solutions in NCERT solutions for class 11 biology chapter 20 locomotion and movement. However, locomotion generally takes place for the search of food, shelter, mate, suitable breeding grounds, favorable climatic conditions or to escape from enemies/predators. If you are looking for an answer from any other chapter even from any other class then go with NCERT Solutions, there you will get all the answers.

Here are the important topics of CBSE NCERT solutions for class 11 biology chapter 20 locomotion and movement mentioned below:

20.1 Types of Movement

20.2 Muscle

20.2.1 Structure of Contractile Proteins

20.2.2 Mechanism of Muscle Contraction

20.3 Skeletal System

20.4 Joints

20.5 Disorders of Muscular and Skeletal System

You will also get interesting things to read in this chapter like repeated stimulation of muscles which leads to fatigue, don't miss them out as in NCERT solutions for class 11 biology chapter 20 locomotion and movement you will get related questions along with their answers.

After going through the solutions for NCERT class 11 biology chapter 20 locomotion and movement, you must be able to understand all the answers the following questions:

CBSE NCERT solutions for class 11 biology chapter 20 locomotion and movement- Solved Exercise Questions-

Q2. Define sliding filament theory of muscle contraction.

Answer:

Sliding filament theory of muscle contraction

1.The sliding filament theory was mainly proposed to explain the process of muscle contraction. This theory proposes that during muscle contraction the thin filaments slide over the thick filaments leading to shortening of the myofibrils.

2. Each muscle fibre possesses alternate light and dark bands, which contains a specialised contractile protein known as actin and myosin respectively.

3. Actin refers to a thin contractile protein present in the light band and is known as the I-band, on the other hand, myosin is a thick contractile protein present in the dark band and is known as the A-band.

4. An elastic fibre called z line bisects each I-band. to this z line, the thin filament is firmly anchored.  The central part of the thick filament that is not overlapped by the thin filament is known as the H-zone.

5. During muscle contraction, the myosin heads or cross bridges come in close contact with the thin filaments causing the thin filaments to be 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 band remains constant as its original length and the I-band shortens and the H-zone disappears.

Q3. Describe the important steps in muscle contraction.

Answer:

The process of muscle contraction includes the following events 

1. Depolarisation of Sarcolemma- In this event, a signal is sent by the central nervous system through a motor neuron and it reaches the neuromuscular junction or motor end plate. The neuromuscular junction refers to the junction between a motor neuron and the sarcolemma of the muscle fibre. The receiving of the signal by neuromuscular junction causes the acetylcholine which is a neurotransmitter to release and set the action potential in the sarcolemma.

2. Release of Calcium Ions- This step includes the transmission of the action potential by sarcolemma to the sarcoplasmic reticulum to release calcium ions in the sarcoplasm.

3. Conformational Changes in Actin Filaments- The calcium ions thus released binds to the troponin and tropomyosin on active filaments changing the three-dimensional shape of the actin–troponin-tropomyosin complex. This causes the active site for myosin which is found on the actin filament to be exposed. 

4. Activation of Myosin Heads- Later on, the myosin heads also get activated and they release energy by the hydrolysis of ATP resulting in the binding of myosin heads to the active sites present on the actin filaments. This leads to the formation of actin-myosin cross-bridge.

5. Sliding of Actin Filaments over Myosin- After the formation of cross-bridges, the myosin head rotates to pull the actin filament towards the centre of the A-band, i.e. the H-zone. The Z-line attached to the actin filaments is also pulled inwards resulting in the contraction of the sarcomere. During contraction, the I-band shortens, while the A-band retains its length. This causes the muscles to contract. 

Q4. Write true or false. If false change the statement so that it is true.

             (a) Actin is present in thin filament
             (b) H-zone of striated muscle fibre represents both thick and thin filaments.
             (c) Human skeleton has 206 bones.
             (d) There are 11 pairs of ribs in man.
             (e) Sternum is present on the ventral side of the body.

Answer:

(a) Actin is present in thin filament

True statement
 

(b) H-zone of striated muscle fibre represents both thick and thin filaments.

False statement. H -zone of striated muscle fibre is the central part of the thick filament that is not overlapped by the thin filament.
            

(c) Human skeleton has 206 bones

True statement.
          

(d) There are 11 pairs of ribs in man.

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

(e) Sternum is present on the ventral side of the body.

True statement

Q5. Write the difference between :

(a) Actin and Myosin

Answer:

The differences between actin and myosin are as follows:

Actin 

Myosin

Actin refers to the thin contractile protein

Myosin refers to the thick contractile protein

Actin is found in light bands called isotropic bands

Myosin is found in dark bands called anisotropic bands

Q5. Write the difference between :

(b) Red and White muscles

Answer:

Red muscle fibre

White muscle fibre

These are thin and smaller in size

These are thick and larger in size

Due to the presence of myoglobin, they are red in colour               

Due to the presence of only a small amount of myoglobin, they are white in colour

These carry out slow and sustained contractions

These carry out fast contractions for shorter durations. 

Q5. Write the difference between :

(c) Pectoral and Pelvic girdle

Answer:

Pectoral girdle

Pelvic girdle

Skeletal support where forelimbs are attached

Askeletal support where hindlimbs are attached

It includes two bones i.e. clavicle and scapula

It includes three bones i.e.ileum, pubis and ischium

Solutions for NCERT class 11 biology chapter 20 locomotion and movement:

Q6. Match Column I with Column II :

            Column I                       Column II
            (a) Smooth muscle       (i) Myoglobin
            (b) Tropomyosin           (ii) Thin filament
            (c) Red muscle             (iii) Sutures
            (d) Skull                        (iv) Involuntary

Answer:

The correct matching is as follows: a- iv, b- ii, c- i, d- iii

              Column I                       Column II
            (a) Smooth muscle        (iv) Involuntary
            (b) Tropomyosin            (ii) Thin filament
            (c) Red muscle              (i) Myoglobin
            (d) Skull                         (iii) Sutures

Q7. What are the different types of movements exhibited by the cells of human body

Answer:

The different types of movements exhibited by the cells of the human body are as follows: 

1. Amoeboid movement - The leucocytes present in the blood show amoeboid movement. During tissue damage, these blood cells move in an amoeboid manner (by forming temporary pseudopodia)  from the circulatory system towards the site of injury to initiate an Immune response.

2. Ciliary movement- The reproductive cells such as sperms and ova show ciliary movement. The passage of ova through the fallopian tube towards the uterus is facilitated by this movement. 

3. Muscular movement- The muscle cells of the human body show muscular movement. These contract and relax to bring about the movement. E.g. Movements of limbs, tongue and jaws are examples of muscular movements.

Q8. How do you distinguish between a skeletal muscle and a cardiac muscle ?

Answer:

The differences between skeletal muscles and cardiac muscles are as follows: 

Skeletal muscle

Cardiac muscle

 The function of skeletal muscles is voluntary.

Cardiac muscles function involuntarily.

The cells of these muscles are unbranched

The cells of these muscles are branched

INtercalated discs between the cells are absent

Intercalated discs between the cells are present

These consists of alternate light and dark bands

These possess bands that are fainted

These are voluntary in nature

These are involuntary in nature

They help in locomotory actions and body posture

Cardiac muscles help in movements of the heart

Q9. Name the type of joint between the following:-

(a) atlas/axis

Answer:

   (a) atlas/axis possess pivotal joint

Q9. Name the type of joint between the following:-

(b) carpal/metacarpal of thumb

Answer:

(b) carpal/metacarpal of thumb possess saddle joint

CBSE NCERT solutions for class 11 biology chapter 20 locomotion and movement:

Q9. Name the type of joint between the following:-

(c) between phalanges

Answer:

between phalanges hinge joint

Q9.Name the type of joint between the following:-

(d) femur/acetabulum

Answer:

femur/acetabulum possess ball and socket joint.

Q9. Name the type of joint between the following:-

(e) between cranial bones

Answer:

between cranial bones fibrous joints are present

Q9. Name the type of joint between the following:-

(f) between pubic bones in the pelvic girdle

Answer:

between pubic bones in the pelvic girdle ball and socket joints are present.

10. Fill in the blank spaces:

              (a) All mammals (except a few) have __________ cervical vertebra.
              (b) The number of phalanges in each limb of human is __________
              (c) Thin filament of myofibril contains 2 ‘F’ actins and two other proteins namely __________ and                            __________.
              (d) In a muscle fibre Ca++ is stored in __________
              (e) __________ and __________ pairs of ribs are called floating ribs.
              (f) The human cranium is made of __________ bones.

Answer:

              (a) All mammals (except a few) have seven cervical vertebra.
              (b) The number of phalanges in each limb of human is 14.
              (c) Thin filament of myofibril contains 2 ‘F’ actins and two other proteins namely troponin and tropomyosin.
              (d) In a muscle fibre Ca++ is stored in sarcoplasmic reticulum. 
              (e)  11th and 12th pairs of ribs are called floating ribs.
              (f) The human cranium is made of eight bones.

If you are facing any issue in understanding the answers of the above questions, then don't worry and again go through that NCERT Book and try to understand all the concepts of every topic and then write the answers of all these questions by your own and then compare them with NCERT solutions for class 11 biology chapter 20 locomotion and movement. You will see that your knowledge, as well as the understanding of these concepts, will increase and you will be able to explain the answers in a better way.

NCERT Solutions for class 11 Biology

Chapter 1

NCERT solutions for class 11 biology chapter 1 the living world

Chapter 2

Solutions of NCERT for class 11 biology chapter 2 biological classification

Chapter 3

CBSE NCERT solutions for class 11 biology chapter 3 plant kingdom

Chapter 4

NCERT solutions for class 11 biology chapter 4 animal kingdom

Chapter 5

Solutions for NCERT class 11 biology chapter 5 morphology of flowering plants

Chapter 6

CBSE NCERT solutions for class 11 biology chapter 6 anatomy of flowering plants

Chapter 7

NCERT solutions for class 11 biology chapter 7 structural organisation in animals

Chapter 8

Solutions for NCERT Class 11 Biology Chapter 8 Cell: The Unit of Life

Chapter 9

CBSE NCERT Solutions for Class 11 Biology Chapter 9 Biomolecules

Chapter 10

NCERT Solutions for Class 11 Biology Chapter 10 Cell Cycle and Cell Division

Chapter 11

Solutions for NCERT Class 11 Biology Chapter 11 Transport in Plants

Chapter 12

CBSE NCERT Solutions for Class 11 Biology Chapter 12 Mineral Nutrition

Chapter 13

NCERT Solutions for Class 11 Biology Chapter 13 Photosynthesis in Higher Plants

Chapter 14

Solutions for NCERT Class 11 Biology Chapter 14 Respiration in Plants

Chapter 15

CBSE NCERT Solutions for Class 11 Biology Chapter 15 Plant Growth and Development

Chapter 16

NCERT Solutions for Class 11 Biology Chapter 16 Digestion and Absorption

Chapter 17

Solutions for NCERT Class 11 Biology Chapter 17 Breathing and Exchange of Gases

Chapter 18

CBSE NCERT Solutions for Class 11 Biology Chapter 18 Body Fluids and Circulation

Chapter 19

NCERT solutions for class 11 biology chapter 19 excretory products and their elimination

Chapter 20

Solutions for NCERT class 11 biology chapter 20 locomotion and movement

Chapter 21

CBSE NCERT solutions for class 11 biology chapter 21 neural control and coordination

Chapter 22

NCERT solutions for class 11 biology chapter 22 chemical coordination and integration

NCERT Solutions for Class 11- Subject wise

NCERT solutions for Class 11 Maths

Solutions for NCERT Class 11 Chemistry

CBSE NCERT solutions for Class 11 Physics

What are the benefits of the solutions for NCERT class 11 biology chapter 20 locomotion and movement:

  • NCERT is the base of your learning.
  • You will get all the answers to this chapter and it will help you to score good marks in the exam.
  • NCERT solutions for class 11 biology chapter 20 locomotion and movement will also help you with competitive exams like NEET.
  • It will also boost your knowledge with understanding.
  • CBSE NCERT solutions for class 11 biology chapter 20 locomotion and movement will also help you in your 12th board exam.
 

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