Locomotion and MovementNEET Zoology · Class 11 · NCERT Chapter 8

Solution

- Cartilaginous joint: between the vertebrae, not the frontal and parietal bones.
- Pivot joint: between the atlas and axis vertebrae, not the third and fourth cervical vertebrae.
- Hinge joint: between the humerus and the ulna, not the humerus and pectoral girdle.
- Gliding joint: between the carpals, which allows sliding movements. Option (d) is correct.

Solution

Stimulation of a muscle fiber by a motor neuron occurs at the neuromuscular junction, where neurotransmitters are released to trigger muscle contraction. NCERT XI chapter Locomotion and Movement describes this process, so option (a) is correct.

Solution

Production of body heat is the function of adipose tissue.

Solution

Fibrous joint are immovable joints where two bones are connected with the help of fibrous connective tissue.

Solution

Tonus → low level activity of muscles at rest to maintain posture Spasm → Sudden involuntary muscle contraction Fatigue → Decline in muscle activity Tetanus → Sustained muscle contraction in response to successive stimuli

Solution

Smaller animals have higher BMR related with sustained energy production and delayed muscle fatigue. www.vedantu.com 72

Solution

Calcium ions bind to troponin, causing a conformational change that removes the tropomyosin blockage from the active sites on actin, allowing myosin to bind. NCERT XI chapter Locomotion and Movement explains this mechanism of muscle contraction, so option (c) is correct.

Solution

During muscular contraction, the ‘H’ zone disappears, the ‘I’ band reduces in width, myosin hydrolyzes ATP releasing ADP and Pi, and Z-lines attached to actins are pulled inwards. The ‘A’ band does not widen, so option (a) is correct.

Solution

- Cartilaginous Joint (A) is found between adjacent vertebrae in the vertebral column (II).
- Ball and Socket Joint (B) is found between the humerus and pectoral girdle (IV).
- Fibrous Joint (C) is found between flat skull bones (I).
- Saddle Joint (D) is found between the carpal and metacarpal of the thumb (III).

Solution

Sarcoplasmic reticulum stores calcium ions, and the striated appearance is due to the arrangement of actin and myosin proteins, making statements B and C correct. The M line is not the functional unit of contraction; the sarcomere is, so statement D is incorrect. Option (c) is the correct choice.

Solution

The correct answer is option (2) as Figure (a) represents skeletal muscle fibres which are closely attached to skeletal bones. In a typical muscle such as triceps and biceps, striated muscle fibres are bundled together in a parallel fashion. Figure (b) represents smooth muscle fibres which are present in the wall of internal organs such as the blood vessels, stomach and intestine. Figure (c) represents cardiac muscle fibres which are exclusively present in the heart.

Solution

The correct answer is option no. (4) as • Fibrous joints do not allow any movement. This type of joint is shown by the flat skull bones which fuse end-to-end with the help of dense fibrous connective tissues in the form of sutures. • Cartilaginous joint is present between the adjacent vertebrae in the vertebral column and this permits limited movements. • Hinge joint is a type of synovial joint present in knee, help in locomotion • Ball and socket joint is also a type of synovial joint present between humerus and pectoral girdle and allows rotational movement.

Solution

Water vascular system in Echinoderms helps in locomotion, capture and transport of food and respiration.

Excretory system is absent in echinoderms. Excretion takes place through general body surface.