Test: Locomotion & Movement - 2 - NEET MCQ

Pivot joint: Between atlas and axis called atlanto-axial joint.

Topic in NCERT: Joints

Line in NCERT: "pivot joint (between atlas and axis)"

Muscle fibres have properties of excitability, elasticity and contractility but conductivity is not present in muscles fibers. These fibres help in movement of different body parts.

Topic in NCERT: Muscle properties

Line in NCERT: "muscles possess excitability, contractility, extensibility and elasticity."

Hip bone or pelvic girdle consists of two coxal bones. Each coxal bone is formed by the fusion of three bones- ilium, ischium and pubis
Line in NCERT: Pelvic girdle consists of two coxal bones (Figure 17.10). Each coxal bone is formed by the fusion of three bones – ilium, ischium and pubis. At the point of fusion of the above bones is a cavity called acetabulum to which the thigh bone articulates. The two halves of the pelvic girdle meet ventrally to form the pubic symphysis containing fibrous cartilage.

Each ‘F’ actin is a polymer of monomeric ‘G’ (Globular) actins.

Topic in NCERT: Mechanism of muscle contraction

Line in NCERT: Each actin (thin) filament is made of two ‘F’ (filamentous) actins helically wound to each other. Each ‘F’ actin is a polymer of monomeric ‘G’ (Globular) actins
Each myosin (thick) filament is also a polymerised protein. Many monomeric proteins called Meromyosins (Figure 17.3b) constitute one thick filament. Each meromyosin has two important parts, a globular head with a short arm and a tail, the former being called the heavy meromyosin (HMM) and the latter, the light meromyosin (LMM). The HMM component, i.e.; the head and short arm projects outwards at regular distance and angle from each other from the surface of a polymerised myosin filament and is known as cross arm. The globular head is an active ATPase enzyme and has binding sites for ATP and active sites for actin.
"utilising the energy from atp hydrolysis, the myosin head now binds to the exposed active sites on actin to form a cross bridge (figure 17.4)."

Humans possess 26 vertebrae in the vertebral column. These vertebrae are divided into five different regions, namely the cervical (7), thoracic (12), lumbar (5), sacral (1-fused) and coccygeal (1-fused) regions.

Topic in NCERT: Skeletal system

Line in NCERT: "the vertebral column is differentiated into cervical (7), thoracic (12), lumbar (5), sacral (1-fused) and coccygeal (1-fused) regions starting from the skull."

• A: Light band present on the myofibril is called I-band or isotropic band. It consists of only actin filaments.
• B: Sarcoplasm is enclosed by sarcolemma which contains many nuclei.
• C: Myofibril is made up of two types of myofilaments which are thick and thin.
• D: Sarcolemma is the plasma membrane of muscle fibre.
• E: Nucleus
• F: Dark band present on the myofibril is called A-band or anisotropic band.

So, the correct answer is 'A- light band, B- sarcoplasm, C- myofibril, D- sarcolemma, E- nucleus, F- dark band'.

Topic in NCERT: Myofibrils

Line in NCERT: "each myofibril has alternate dark and light bands on it."

The label x is H-zone, y is I band and z is A band.

Topic in NCERT: H zone

Line in NCERT: "the central part of thick filament, not overlapped by thin filaments is called the 'h' zone."
Diagram in NCERT:

Statement 1: Each pectoral girdle has two pairs of bones: a pair of clavicles and a pair of scapulae. The pectoral girdle, also known as the shoulder girdle, is a skeletal structure that connects the upper limb to the axial skeleton.
Statement 2: The head of the humerus bone articulates with the glenoid cavity of the pectoral girdle.
Hence both are correct.

Topic in NCERT: Pectoral girdle

Line in NCERT: "each half of pectoral girdle consists of a clavicle and a scapula." "below the acromion is a depression called the glenoid cavity which articulates with the head of the humerus to form the shoulder joint."

Tetany is caused due to rapid spasms (wild contractions) in muscle due to low Ca++ inbody fluid.

Topic in NCERT: Muscle disorders

Line in NCERT: "tetany: rapid spasms (wild contractions) in muscle due to low ca++ in body fluid."

The chemical energy is converted into mechanical energy during muscle contraction and the chemical is a neurotransmitter. In a contracted muscle, volume remains the same and a contracted muscle becomes shorter and thicker.

Topic in NCERT: Muscle contraction

Line in NCERT: "muscle contraction is initiated by a signal sent by the central nervous system (cns) via a motor neuron. a motor neuron alongwith the muscle fibres connected to it constitute a motor unit. the junction between a motor neuron and the sarcolemma of the muscle fibre is called the neuromuscular junction or motor-end plate. a neural signal reaching this junction releases a neurotransmitter (acetyl choline) which generates an action potential in the sarcolemma."

Hip bone is called as innominate bone, kneebone is called as patella, collarbone is called as clavicle and immovable joint is called suture.

Statement i) is correct. Lactic acid does accumulate in muscle cells during vigorous exercise when there is insufficient oxygen available to completely break down glucose aerobically. The process by which glucose is converted to lactic acid without oxygen is called anaerobic respiration, which provides energy quickly to the muscles.

Statement ii) is also correct. Since lactic acid is formed by anaerobic respiration, it does not require oxygen. This process is beneficial during intense exercise when the demand for energy is high, but the supply of oxygen is limited.

Statement iii) is incorrect. Oxygen debt (or oxygen deficit) refers to the amount of oxygen required after physical exercise to convert accumulated lactic acid back into glucose and to restore muscle ATP and creatine phosphate levels. This is not about the reduction of oxygen consumption during exercise but rather the additional oxygen required after exercise to recover.

Therefore, the correct answer is B: only statement i) and ii) are correct.

Line in NCERT : Repeated activation of the muscles can lead to the accumulation of lactic acid due to anaerobic breakdown of glycogen in them, causing fatigue.

Myasthenia gravis is an auto immune disorder affecting neuromuscular junction leading to fatigue, weakening and paralysis of skeletal muscle.
Topic in NCERT : DISORDERS OF MUSCULAR AND SKELETAL SYSTEM
Line in ncert : ​​​​​​​Myasthenia gravis: Auto immune disorder affecting neuromuscular junction leading to fatigue, weakening and paralysis of skeletal muscle

• The light bands contain actin and is called Isotropic band, whereas the dark band called ‘A’ or Anisotropic band contains myosin.
• Actin filaments are thinner as compared to the myosin filaments, hence are commonly called thin and thick filaments respectively.
• In the centre of each ‘I’ band is an elastic fibre called ‘Z’ line which bisects it.

Topic in NCERT: Structure of contractile proteins

Line in NCERT: "the thin filaments are firmly attached to the 'z' line."

- The Assertion is true because red fibres do indeed have a high content of myoglobin, which gives them a reddish appearance.

- The Reason is false because red fibres primarily rely on aerobic metabolism due to their high myoglobin and mitochondrial content, not anaerobic metabolism.

- Since the Assertion is true and the Reason is false, Option B is correct as both statements are true, but the Reason does not correctly explain the Assertion.
Line in NCERT: Muscle contains a red coloured oxygen storing pigment called myoglobin. Myoglobin content is high in some of the muscles which gives a reddish appearance. Such muscles are called the Red fibres. These muscles also contain plenty of mitochondria which can utilise the large amount of oxygen stored in them for ATP production. These muscles, therefore, can also be called aerobic muscles