NCERT Solutions for Class 11 Biology Chapter 20

Chapter 20 Biology Class 11 – Locomotion and Movement introduces students to new concepts of Human Physiology, and that is why many students find it to be a difficult chapter. The practise questions at the end of the chapter can help students get a better understanding of the concepts. But, how will students get to know if they have answered a question correctly?

The NCERT Solutions for Class 11 Biology Chapter 20 by Extramarks help students by providing the correct and reliable answers to the questions. The solutions are prepared by the subject matter experts, so students can rely on them for accuracy. 

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

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

The NCERT Solutions for Class 11 Biology Chapter 20 are excellent reference material for students who are preparing for their Class 11 examinations and have doubts that come up, particularly in Chapter 20. 

Since all the NCERT textbook questions are answered in Chapter 20 Biology Class 11 NCERT Solutions by Extramarks, students do not have to look out for other solutions to prepare for their exams.

NCERT Solutions of Locomotion and Movement Class 11 

Chapter 20 Biology Class 11 – Locomotion and Movement is a chapter from the Human Physiology Unit (Unit V). Occurrences of various forms of locomotion in unicellular organisms and in human bodies are discussed in this chapter along with the different types of muscle movements, skeletal structure, and joint movement of the human body. Disorders of the muscle and skeleton system are covered in this chapter as well. Colourful diagrams are bound to incite student’s interest.

This chapter imparts information about voluntary and involuntary action of muscles, and disorders like arthritis. It gives in-depth explanations of the functions of joints and bones.

When solving questions given at the end of the chapter, students can refer to NCERT Solutions for Class 11 Biology Chapter 20 by Extramarks.

NCERT Solutions of Chapter 20 Biology Class 11- Marks Distribution

Chapter 20 – Locomotion and Movement is one of the seven chapters in Unit V of CBSE Biology Class 11. Unit V has a weightage of 18 marks in the final examinations. A 20% weightage is given to this unit in NEET.

Benefits of NCERT Solutions for Class 11 Biology Locomotion and Movement 

NCERT Solutions Class 11 Biology Chapter 20 provided by Extramarks comprise all the questions that are a part of the Chapter 20 Biology Class 11 – Locomotion and Movement. Here is how these solutions will aid students in scoring better in their exams. 

  • All the questions from the textbook are answered and all answers are framed in a way that is simple and understandable.
  • Students can access the solutions online and offline.
  • The solutions are curated by subject matter experts, which ensures 100 per cent accuracy.
  • Diagrams and examples are given in the answers to explain them in a better way to students.

Related Questions

Question: Which statement is correct for muscle contraction?

  1. Length of two Z-line increases
  2. Length of H-zone decreases
  3. Length of the A-band remains constant
  4. Length of A- band decreases

Answer: 4. Length of the A-band remains constant.

Explanation: During muscle contraction, thick filaments have thin filaments dropping over them. Muscular contraction is initiated due to a signal sent by the central nervous system through the motor neuron. The combining of calcium ions with troponin results in muscle contraction. During this contraction, the Z-lines draw closer together and the sarcomere shortens. A-band’s length remains constant while the H-zone narrows and I-bands shorten. Muscle contraction is terminated by muscle relaxation. Muscle relaxation is basically the muscle fibres’ restoration to their low tension-producing rate. 

Question: The dark colour of the breast muscles of a bird of flight is due to the high concentration of

  1. Mitochondria
  2. Myoglobin
  3. Haemoglobin
  4. Both myoglobin and mitochondria

Answer: 2) Myoglobin

Explanation: Oxygen-carrying protein called myoglobin is incorporated in the muscle fibres of the breasts of birds. Oxygen received from red blood cells is transported by the myoglobin to the muscle cells’ mitochondria. Here this oxygen is utilised in cellular respiration for producing energy. A high concentration of myoglobin in the breast muscles of birds is what causes these muscles to be a dark colour. 

Question: The smallest functional unit of the striated muscle is called as

  1. Myosin
  2. Fibril
  3. Sarcomere
  4. Sarcoplasm

Answer: 3) Sarcomere

Explanation: The smallest or basic unit of striated muscle tissue is Sarcomere. Sarcomeres can only be found in striated muscles. Striated muscles consist of skeletal muscles and cardiac muscle cells. Striated muscles are different as compared to smooth muscles with sarcomeres. While striated muscles are repeating units between two Z-lines, sarcomeres enable them to contract. The creation of force and contraction are the functions of these muscles.

Question: Which of the following is a locomotory organ in the snail?

  1. Outer shell
  2. Muscular foot
  3. Muscular rings
  4. All of the above

Answer: 2) Muscular foot

Explanation: Utilising muscle contractions in their foot muscles, snails deform a layer of mucus beneath them in order to propel themselves. This type of unique locomotion enables snails to move through obstacles (including being able to climb steep inclines). A snail’s locomotory organ is its muscular foot. 

Question: An example of amoeboid movement is

  1. Limbs
  2. Leucocytes
  3. Trachea
  4. None of the above

Answer: 2) Leucocytes

Explanation: A characteristic feature of every living organism is movement. Cells in the human body display different types of movement which are as follows:

Ciliary Movement: This movement is exhibited by reproductive cells like sperms and ova. 

Amoeboid movement: Amoeboid movement is exhibited by the leukocytes or leucocytes in the human blood.

Muscular movement: Muscle tissues present inside digestive organs, heart, and blood vessels aid in the movement of substances throughout the body. Therefore, leukocytes are an example of amoeboid movement.

Question: The main advantage of bipedal locomotion is:

  1. Availability of hands for other uses
  2. Increased speed
  3. Better body balance
  4. Reduced weight

Answer: 1) Availability of hands for other uses

Explanations: A terrestrial locomotion that has an organism moving about on its legs or two rear limbs is called bipedal locomotion. This form of locomotion leaves the forelimbs free for other tasks and purposes. 

Question: The movement of the whole animal from one place to another place is called

  1. Skeletal movement
  2. Non-skeletal movement
  3. Movement
  4. Locomotion

Answer: 4) Locomotion

Explanation: The movement of a part of the body resulting in a change in location and position of the organism is called locomotion. Jumping, running, walking, crawling, flying, slithering, climbing, etc. are movements carried out by multicellular organisms. Therefore, a whole animal’s movement from one place to another is known as locomotion. 

FAQs (Frequently Asked Questions)

  • A red muscle fibre is smaller and thinner than a white muscle fibre. 
  • Red muscle fibre contains more mitochondria than white muscle fibre. 
  • The amount of myoglobin in red muscle fibre is more than that of white muscle fibre. This comparatively more quantity of myoglobin in red muscle fibre is what gives it red colour while the less quantity in white muscle fibre is the reason for its white colour. 
  • Energy is provided by white muscle fibre through anaerobic respiration while red muscle fibre does so by aerobic respiration. 

The different types of muscles in existence are as follows:

Visceral muscles

The inner walls of hollow visceral organs in the human body see the presence of visceral muscles. These muscles look smoother than skeletal muscles which is why they are called non-striated muscles or smooth muscles. These are also called involuntary muscles. Examples of these types of muscles include reproductive tracts, alimentary canal, etc. 

Skeletal muscles 

The primary functions of skeletal muscles involve changes in posture and locomotory actions. These muscles are linked with the human body’s skeletal attributes. Their appearance is stripped when one views them under a microscope which is why they are called striated muscles. These muscles are generally under the nervous system’s control so they are called voluntary muscles. 

Cardiac muscles

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