NEET · Biology —

Locomotion and Movement appeared 3 times across 1 year — 3.3% of Biology. This question is from Mechanism of Muscle Contraction.

Year 2024 Total
Questions 3 3
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Choose the correct statements regarding muscle contraction. A. A motor neuron carries a signal sent by the Central Nervous System (CNS) to the sarcolemma of the muscle fibre. B. The neural signal generates an action potential which causes the release of Ca⁺⁺ into sarcoplasm. C. Increase in Ca⁺⁺ inactivates the actin for breaking cross bridges. D. Actin binds to the myosin head to form a cross bridge. E. Shortening of sarcomere takes place, by pulling actin filaments towards the centre of 'A' band. Choose the correct answer from the options given below :

Solution & Explanation

Core Logic

Statements A, B, D and E are correct while statement C is incorrect. A neural signal reaching the neuromuscular junction releases a neurotransmitter (Acetylcholine) which generates an action potential in the sarcolemma. This spreads through the muscle fibre and causes the release of Ca⁺⁺ into the sarcoplasm. This Ca⁺⁺ binds to the subunit of troponin on actin filaments and thereby removes the masking of active sites for myosin on actin, facilitating the FORMATION of a cross bridge (not breaking them). Thus, increase in Ca⁺⁺ activates actin, contrary to statement C.

Pattern Recognition

Calcium binding to troponin exposes myosin-binding sites. This initiates the sliding filament mechanism. Calcium does not break cross-bridges; ATP does.

Chapter Mix

Class 11 Biology: Locomotion and Movement

Reference Study Guides

Locomotion And Movement

More Locomotion and Movement Previous-Year Questions

Q158 neet_2026_03_may_morning Disorders of Muscular and Skeletal System
Match List I with List II related to muscular/skeletal system:
List IList II
A. TetanyI. Inflammation of joints
B. ArthritisII. Autoimmune disorder affecting neuromuscular junction
C. Myasthenia gravisIII. Wild contraction in muscle due to low Ca⁺⁺ in body fluid
D. Muscular dystrophyIV. Progressive degeneration of skeletal muscle
Choose the correct answer from the options given below:
  • A. A-III, B-I, C-II, D-IV
  • B. A-IV, B-III, C-II, D-I
  • C. A-I, B-II, C-III, D-IV
  • D. A-III, B-II, C-I, D-IV

Solution

Core Logic

Arthritis is an inflammation of joints (B arrow I). Tetany is rapid spasms (wild contractions) in muscle due to low Ca⁺⁺ in body fluids (A arrow III). Muscular dystrophy is progressive degeneration of skeletal muscle mostly due to genetic disorder (D arrow IV). Myasthenia gravis is an autoimmune disorder affecting neuromuscular junction leading to fatigue, weakening and paralysis of skeletal muscle (C arrow II).

Step 1: Final Conclusion

Hence, A-III, B-I, C-II, D-IV is the correct match.

Pattern Recognition

Connect 'autoimmune' directly to Myasthenia gravis. Connect 'genetic/progressive degeneration' to Muscular dystrophy. Connect 'low calcium/spasms' to Tetany.

Chapter Mix

Class 11 Biology: Locomotion and Movement

Q168 neet_2026_03_may_morning Skeletal System
Which of the following statements are correct with reference to human endoskeleton? A. Human skull is monocondylic. B. The joint between any two adjoining vertebrae is a cartilaginous joint. C. In human beings, the number of cervical vertebrae is seven. D. All ribs except the last 2 pairs are bicephalic. E. The occipital bone of skull is articulated with atlas vertebra. Choose the correct answer from the options given below:
  • A. A, B and D only
  • B. B and E only
  • C. B, C and E only
  • D. C, D and E only

Solution

Core Logic

(A) Incorrect: Human skull is dicondylic. The skull region articulates with the superior region of the vertebral column with the help of two occipital condyles. (B) Correct: The joint present between the adjacent vertebrae of vertebral column is cartilaginous joints. (C) Correct: There are 7 cervical vertebrae in almost all mammals including human beings. (D) Incorrect: All ribs of humans are bicephalic, i.e., they have two articulation surfaces on their dorsal end. (E) Correct: The occipital bone of the skull articulates with the atlas vertebra via occipital condyles, forming the atlanto-occipital joint.

Step 1: Final Conclusion

The correct statements are B, C, and E.

Pattern Recognition

Humans are dicondylic. All ribs are bicephalic dorsally. 7 cervical vertebrae is a defining mammalian trait.

Chapter Mix

Class 11 Biology: Locomotion and Movement

More Locomotion and Movement Questions — neet_2026_03_may_morning

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JEE Physics: Waves (+15.5%) | Electrostatics: Concentric Shells (-29.7%) | Modern Physics: Photoelectric Clones (+34.2%) | Mathematics: Definite Integrals (+18.1%) | Chemistry: Coordination Splitting (-11.4%) | JEE Physics: Waves (+15.5%) | Electrostatics: Concentric Shells (-29.7%) | Modern Physics: Photoelectric Clones (+34.2%) | Mathematics: Definite Integrals (+18.1%) | Chemistry: Coordination Splitting (-11.4%)