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 Ca²⁺ into sarcoplasm. C. Increase in Ca²⁺ 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

Related Formula
Increase in Ca²⁺ level arrow Binds to Troponin arrow Unmasks active sites on Actin arrow Cross-bridge formation
Core Logic

Evaluating statements regarding muscle contraction:

  • A (Correct): Motor neurons send signal from CNS to neuromuscular junction.
  • B (Correct): Action potential causes release of Ca²⁺ from sarcoplasmic reticulum into sarcoplasm.
  • C (Incorrect): Increase in Ca²⁺ binds to troponin to UNMASK active sites on actin (it activates actin for cross-bridge formation, not inactivates).
  • D (Correct): Myosin head binds to unmasked active site on actin forming a cross-bridge.
  • E (Correct): Actin filaments are pulled inward toward the center of 'A' band, causing shortening of sarcomere.
Step 1: Conclusion

Statements A, B, D, and E are correct.

Pattern Recognition

Sees: "Ca2+ inactivates actin" (False). Shortcut: Calcium unmasks active sites on actin arrow statement C is false.

Chapter Mix

Class 11 Biology: Locomotion and Movement

Reference Study Guides

Locomotion And Movement

More Locomotion and Movement Previous-Year Questions

Q158 neet_2024_05_may_morning Disorders of Muscular and Skeletal System
Match List I with List II related to muscular/skeletal system:
List IList II
(A) Tetany(I) Inflammation of joints
(B) Arthritis(II) Autoimmune disorder affecting neuromuscular junction
(C) Myasthenia gravis(III) Wild contraction in muscle due to low Ca²⁺ in body fluid
(D) Muscular dystrophy(IV) 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

Related Formula

aligned Tetany &arrow Rapid spasms / wild contractions due to low Ca²⁺ Arthritis &arrow Inflammation of joints Myasthenia Gravis &arrow Autoimmune disorder of neuromuscular junction Muscular Dystrophy &arrow Genetic progressive degeneration of skeletal muscle aligned

Core Logic

Matching each disorder with its clinical description:

  • (A) Tetany arrow Wild contraction in muscle due to low Ca²⁺ in body fluid (III)
  • (B) Arthritis arrow Inflammation of joints (I)
  • (C) Myasthenia gravis arrow Autoimmune disorder affecting neuromuscular junction (II)
  • (D) Muscular dystrophy arrow Progressive degeneration of skeletal muscle (IV)
Step 1: Result

The correct combination is A-III, B-I, C-II, D-IV.

Pattern Recognition

Sees: "Tetany Arthritis Myasthenia gravis Muscular dystrophy". Shortcut: Arthritis = Inflammation of joints (B-I); Tetany = low calcium spasms (A-III).

Chapter Mix

Class 11 Biology: Locomotion and Movement

Q168 neet_2024_05_may_morning Human Skeletal Anatomy
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

Related Formula

Human Skull = Dicondylic (2 occipital condyles), Cervical Vertebrae = 7, All 12 pairs of ribs = Bicephalic

Core Logic

Evaluating endoskeleton statements:

  • A (Incorrect): Human skull is dicondylic (possesses two occipital condyles).
  • B (Correct): Adjacent vertebrae are joined by cartilaginous joints permitting limited movement.
  • C (Correct): Almost all mammals, including humans, have 7 cervical vertebrae.
  • D (Incorrect): ALL ribs in humans are bicephalic (have two articulation heads on dorsal end).
  • E (Correct): Occipital condyles of skull articulate with atlas vertebra (1st cervical vertebra).
Step 1: Conclusion

Statements B, C, and E are correct.

Pattern Recognition

Sees: "human skull monocondylic" (False, dicondylic). Shortcut: Eliminate options containing A or D.

Chapter Mix

Class 11 Biology: Locomotion and Movement

More Locomotion and Movement Questions — neet_2024_05_may_morning

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Rankbit System
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%)