NEET Exam  >  NEET Notes  >  Biology Class 11  >  NCERT Solutions: Locomotion & Movement

Locomotion & Movement NCERT Solutions | Biology Class 11 - NEET PDF Download

Q1: Draw the diagram of a sarcomere of skeletal muscle showing different regions.
Ans: The diagrammatic representation of a sarcomere is as follows:

Sarcomere of skeletal muscleSarcomere of skeletal muscle


Q2: Define sliding filament theory of muscle contraction. 
Ans: The sliding filament theory explains the process of muscle contraction during which the thin filaments slide over the thick filaments, which shortens the myofibril.
Each muscle fibre has an alternate light and dark band, which contains a special contractile protein, called actin and myosin respectively. Actin is a thin contractile protein present in the light band and is known as the I-band, whereas myosin is a thick contractile protein present in the dark band and is known as the A-band. There is an elastic fibre called z line that bisects each I-band. The thin filament is firmly anchored to the z line. The central part of the thick filament that is not overlapped by the thin filament is known as the H-zone.

Sliding filament theory of muscle contractionSliding filament theory of muscle contraction

During muscle contraction, the myosin heads or cross bridges come in close contact with the thin filaments. As a result, the thin filaments are 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.
Ans: During skeletal muscle contraction, the thick filament slides over the thin filament by a repeated binding and releases myosin along the filament. This whole process occurs in a sequential manner.

Steps in muscle contractionSteps in muscle contraction

  • 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.
  • Stage 6: This process of formation and breaking down of cross bridges continues until there is a drop in the stimulus, which causes an increase in calcium. As a result, the concentration of calcium ions decreases, thereby masking the actin filaments and leading to muscle relaxation.


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.
Ans:
(a) True
(b) False
(c) True
(d) False
(e) True

Q5: Write the difference between:
(a) Actin and Myosin
(b) Red and White muscles
(c) Pectoral and Pelvic girdle
Ans: (a) Actin and Myosin
Locomotion & Movement NCERT Solutions | Biology Class 11 - NEET

 (b) Red and White muscles
Locomotion & Movement NCERT Solutions | Biology Class 11 - NEET

 (c) Pectoral and Pelvic girdle
Locomotion & Movement NCERT Solutions | Biology Class 11 - NEET


Q6: Match Column I with Column II: 
Locomotion & Movement NCERT Solutions | Biology Class 11 - NEET

Ans:
Locomotion & Movement NCERT Solutions | Biology Class 11 - NEET

 
Q7: What are the different types of movements exhibited by the cells of human body?
Ans: Movement is a characteristic feature of living organisms. The different types of movement exhibited by cells of the human body are:

  • Amoeboid movement: Leukocytes present in the blood show amoeboid movement. During tissue damage, these blood cells move from the circulatory system towards the injury site to initiate an immune response.
  • Ciliary movement: 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.
  • Muscular movement: Muscle cells show muscular movement.


Q8: How do you distinguish between a skeletal muscle and a cardiac muscle? 
Ans:
Locomotion & Movement NCERT Solutions | Biology Class 11 - NEET
Q9:   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) atlas/axis: Pivotal joint
(b) carpal/metacarpal of thumb: Saddle joint
(c) between phalanges: Hinge joint
(d) femur/acetabulum: Ball and socket joint
(e) between cranial bones: Fibrous joint
(f) between pubic bones in the pelvic girdle: Ball and socket joint

Q10:  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.

Ans: (a) All mammals (except a few) have Seven cervical vertebra.
(b) The number of phalanges in each limb of a 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 the sarcoplasmic reticulum.
(e) 11th and 12th pairs of ribs are called floating ribs.
(f) The human cranium is made up of eight bones.

The document Locomotion & Movement NCERT Solutions | Biology Class 11 - NEET is a part of the NEET Course Biology Class 11.
All you need of NEET at this link: NEET
200 videos|414 docs|226 tests

Up next

FAQs on Locomotion & Movement NCERT Solutions - Biology Class 11 - NEET

1. How do muscles work in the process of locomotion?
Ans. Muscles work by contracting and relaxing to create movement. When a muscle contracts, it shortens and pulls on the bone it is attached to, causing movement. This contraction is powered by energy derived from ATP molecules.
2. What role do joints play in the movement of the body?
Ans. Joints are the points where two or more bones meet. They allow for movement and flexibility in the body. Different types of joints, such as hinge joints, ball and socket joints, and pivot joints, enable various types of movement like bending, rotating, and swinging.
3. How does the nervous system control movement and coordination?
Ans. The nervous system controls movement and coordination through the brain and spinal cord. The brain sends signals to the muscles via the nervous system to initiate movement, while the spinal cord helps in coordinating reflex actions and automatic movements.
4. What are the different types of locomotion seen in animals?
Ans. Animals exhibit various types of locomotion such as walking, running, flying, swimming, crawling, hopping, and slithering. Each type of locomotion is adapted to the animal's body structure and habitat.
5. How do skeletal and muscular systems work together to facilitate movement?
Ans. The skeletal system provides the framework for the body, supporting muscles and allowing for attachment points. Muscles work in conjunction with the skeletal system to move the body parts by contracting and relaxing, resulting in coordinated movement.
200 videos|414 docs|226 tests
Download as PDF

Up next

Explore Courses for NEET exam

How to Prepare for NEET

Read our guide to prepare for NEET which is created by Toppers & the best Teachers
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
10M+ students study on EduRev
Related Searches

Viva Questions

,

Locomotion & Movement NCERT Solutions | Biology Class 11 - NEET

,

Sample Paper

,

video lectures

,

study material

,

Locomotion & Movement NCERT Solutions | Biology Class 11 - NEET

,

Previous Year Questions with Solutions

,

practice quizzes

,

shortcuts and tricks

,

Locomotion & Movement NCERT Solutions | Biology Class 11 - NEET

,

past year papers

,

ppt

,

Important questions

,

Free

,

Exam

,

pdf

,

Summary

,

MCQs

,

mock tests for examination

,

Extra Questions

,

Semester Notes

,

Objective type Questions

;