Frequently Asked Questions

NCERT Solutions Class 11 Biology Chapter 17 - Locomotion and Movement

NCERT Solutions for Class 11 Biology Chapter 17 (Locomotion and Movement) explain how muscles, bones, and joints work together to produce movement and help the body change its position. The chapter covers the types of movement, the structure of muscle fibres, the sliding filament theory, the human skeletal system, different types of joints, and common muscular and skeletal disorders. Students can understand the difference between movement and locomotion and learn how these processes take place in the human body.

NCERT Solutions for Class 11 Biology Chapter 17 by ALLEN provide clear explanations of important topics such as sarcomeres, actin and myosin filaments, the role of calcium ions and ATP in muscle contraction, and the classification of bones and joints. Students can also learn about the axial and appendicular skeleton, different types of muscles, and disorders such as arthritis, osteoporosis, and muscular dystrophy. These solutions follow the concepts covered in NCERT Class 11 Biology Chapter 17 and help students prepare for school exams and NEET.

1.0NCERT Solutions for Class 11 Biology Chapter 17 Locomotion and Movement: Key Concepts

Class 11 Biology Chapter 17, Locomotion and Movement, explains how muscles, bones, and joints work together to produce movement and help the body maintain its posture. The chapter covers different types of movement, muscle structure, the mechanism of muscle contraction, the human skeletal system, types of joints, and common muscular and skeletal disorders.

Types of Movement: Understand amoeboid movement through pseudopodia, ciliary movement in the respiratory tract, and muscular movement in body parts such as limbs, jaws, and the tongue.
Types of Muscles: Learn about skeletal, smooth (visceral), and cardiac muscles, including their structure, location, and functions.
Structure of Muscle Fibres: Understand the structure of muscle fibres, sarcomeres, and the contractile proteins actin and myosin.
Mechanism of Muscle Contraction: Learn about the sliding filament theory and the roles of calcium ions and cross-bridges in muscle contraction.
Human Skeletal System: Study the 206 bones of the adult human skeleton, divided into the axial skeleton (skull, vertebral column, ribs, and sternum) and the appendicular skeleton (limbs and girdles).
Types of Joints: Understand fibrous, cartilaginous, and synovial joints, along with examples such as hinge, pivot, and ball-and-socket joints.
Disorders of the Muscular and Skeletal Systems: Learn about myasthenia gravis, muscular dystrophy, tetany, arthritis, osteoporosis, and gout.

2.0NCERT Solutions Class 11 Biology Chapter 17 - Locomotion and Movement: Detailed Solutions

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

Ans.

Structure of a sarcomere showing Z lines, A band, I band, H zone, primary and secondary myofilaments, and cross bridges.

Define sliding filament theory of muscle contraction.

Ans. According to sliding filament theory of muscle contraction, the actin and myosin filaments slide past each other with the help of crossbridges to reduce the length of the sarcomeres.

Describe the important steps in muscle contraction.

Ans. The important steps in muscle contraction are:

(i) A nerve impulse reaches the neuromuscular junction and causes the release of acetylcholine (ACh). (ii) ACh generates an action potential in the sarcolemma, which spreads through the muscle fibre. (iii) This stimulates the release of $Ca^{2 +}$ ions into the sarcoplasm from the sarcoplasmic reticulum. (iv) $Ca^{2 +}$ binds to troponin, causing a change in the position of the tropomyosin and exposing the active sites on actin. (v) The myosin heads bind to actin and form cross-bridges. (vi) Using energy from ATP, the myosin heads pull the actin filaments towards the centre of the sarcomere. (vii) The Z-lines move closer, shortening the sarcomere and causing muscle contraction. (viii) When stimulation stops, $Ca^{2 +}$ is pumped back into the sarcoplasmic reticulum, the active sites are covered again, and the muscle relaxes.

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.

Ans.

(a) True (b) False - H-Zone of striated muscle fibres represents only thick filaments. (c) True (d) False - There are 12 pairs of ribs in man. (e) True

Write the differences between: (a) Actin and Myosin (b) Red and White muscles (c) Pectoral and Pelvic girdle

Ans.

(a)

Actin filaments (Thin myofilaments)	Myosin filaments (Thik myofilaments)
Found in both A and I bands.	Found only in A band of sarcomere.
Cross bridges absent, hence have smooth surface.	Cross bridges present, hence have rough surface.
Free at one end and are joined to Z-line by other end.	Free at both the ends.
Consist of 3 proteins : actin, tropomyosin and troponin.	Consist of 2 proteins : myosin and mearomyosin.
Slide into H-zone during muscle contraction.	Do not slide during muscle contraction.

(b)

Red muscle fibres	White muscle fibres
They are thin.	They are much thicker.
They contain abundant mitochondria, low glycogen content and poorly formed sarcoplasmic reticulum.	They are poor in mitochondria, and have abundant glycogen granules and well-formed sarcoplasmic reticulum.
They are dark red as they contain abundant pigment myoglobin.	They are light in colour as they have very little myoglobin.
Their myoglobin $O_{2}$ as oxymyoglobin that releases $O_{2}$ for oxidation during muscle contraction.	hey have little or no store of oxygen.
They get energy for contraction by aerobic respiration.	They get energy for contraction mainly by anaerobic respiration.

(c)

Red muscle fibres	White muscle fibres
It lies on the postero-lateral aspect of the upper region of the thorax.	It is located in the lower part of the trunk.
It consists of 2 dissimilar bones : scapula and clavicle.	It consists of 2 similar bones, innominate.
It provides articulation to the arm bones.	It provides articulation to the bones of the leg.

6. 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

Sol:(a)-(iv), (b)-(ii), (c)-(i), (d)-(iii)

What are the different types of movements exhibited by the cells of human body? Ans. Cells of the human body exhibit three main types of movements, namely, amoeboid, ciliary and muscular. Some specialised cells in our body like macrophages and leucocytes in blood exhibit amoeboid movement. It is effected by pseudopodia formed by the streaming of protoplasm (as in Amoeba). Cytoskeletal elements like microfilaments are also involved in amoeboid movement. Ciliary movement occurs in most of our internal tubular organs which are lined by ciliated epithelium. The coordinated movements of cilia in the trachea help us in removing dust particles and some of the foreign substances inhaled along with the atmospheric air. Passage of ova through the female reproductive tract is also facilitated by the ciliary movement. Movement of our limbs, jaws, tongue, etc, require muscular movement. The contractile property of muscles are effectively used for locomotion and other movements by human beings and majority of multicellular organisms. Locomotion requires a perfect coordinated activity of muscular, skeletal and neural systems. In this chapter, you will learn about the types of muscles, their structure, mechanism of their contraction and important aspects of the skeletal system.
How do you distinguish between a skeletal muscle and a cardiac muscle?

Ans. We can distinguish between a skeletal muscle and a cardiac muscle on the basis of the features discussed in the following table:

Skeletal or striated muscle	Cardiac muscle
They are present in the limbs, body walls, tongue, pharynx and beginning of oesophagus.	They are present in wall of the heart, pulmonary veins and superior vena cava.
Fibres unbranched.	Fibres branched.
Multinucleate	Uninucleate
Light and dark bands present.	Faint light and dark bands present.
Nerve supply from central nervous system.	Nerve supply from the brain and autonomic nervous system.
Very rapid contraction.	Rapid contraction.
They soon get fatigued	They never get fatigued.
Voluntary	Involuntary

9. Name the type of joint between the following: (a) atlas/axis (b) carpal/metacarpal of thumb (c) between phalanges (d) femur/acetabulum (e) between cranial bones (f) between pubic bones in the pelvic girdle

Ans.

(a) Pivot joint (b) Saddle joint (c) Hinge joint (d) Ball and socket joint (e) Fibrous joint (f) Cartilaginous joint

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 two '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.

Ans.

(a) 7 (b) 14 (c) tropomyosin, troponin (d) sarcoplasmic reticulum (e) 11th and 12th (f) 8

3.0NCERT Class 11 Biology – Chapter-Wise Solutions & Explanations

Get chapter-wise NCERT Solutions for Class 11 Biology with easy answers to all textbook questions. Learn important topics, revise each chapter, and prepare well for your Biology exams.

Chapter Number	Chapterwise NCERT Solutions
Chapter 1	The Living World
Chapter 2	Biological Classification
Chapter 3	Plant Kingdom
Chapter 4	Animal Kingdom
Chapter 5	Morphology of Flowering Plants
Chapter 6	Anatomy of Flowering Plants
Chapter 7	Structural Organisation in Animals
Chapter 8	Cell: The Unit of Life
Chapter 9	Biomolecules
Chapter 10	Cell Cycle and Cell Division
Chapter 11	Photosynthesis in Higher Plants
Chapter 12	Respiration in Plants
Chapter 13	Plant Growth and Development
Chapter 14	Breathing and Exchange of Gases
Chapter 15	Body Fluids and Circulation
Chapter 16	Excretory Products and their Elimination
Chapter 18	Neural Control and Coordination
Chapter 19	Chemical Coordination and Integration

4.0Key Features of NCERT Solutions for Class 11 Biology Chapter 17

Sarcomere Structure and Muscle Contraction: Understand the A band, I band, H zone, and Z line, and learn how these parts change during muscle contraction according to the sliding filament theory.
Human Skeletal System: Learn about the 206 bones in the adult human skeleton and their division into the axial and appendicular skeletons, with their main parts and locations.
Role of Calcium Ions and ATP: Understand how calcium ions expose the active sites on actin and how ATP helps myosin detach from actin during muscle contraction.
Red and White Muscle Fibres: Compare red and white muscle fibres based on myoglobin content, mitochondria, and sarcoplasmic reticulum to understand their structure and functions.
Prepared by ALLEN Expert Faculty: Study the anatomical terms, muscle structures, and physiological processes explained by ALLEN subject experts according to the concepts covered in NCERT Class 11 Biology Chapter 17.
Types of Joints in the Human Body: Understand the classification of fibrous, cartilaginous, and synovial joints based on their structure and range of movement, with suitable examples.
Complete NCERT Exercise Solutions: Find clear answers to NCERT textbook questions on locomotion and movement to understand important concepts and prepare for school and competitive exams.