Home
Class 12
BIOLOGY
During muscle contraction, what could be...

During muscle contraction, what could be the correct sequence ?
A. Release of calcium ions into the sarcoplasm.
B. Release of Acetylcholine.
C. Sliding of actin filaments over each other.
D. Break down of ATP to form a cross bridge.

A

(a) A-D-B-C

B

(b) A-B-D-C

C

(c) B-A-C-D

D

(d) B-A-D-C

Text Solution

AI Generated Solution

The correct Answer is:
To determine the correct sequence of events during muscle contraction, we can break down the process into a series of steps: 1. **Release of Acetylcholine (B)**: The process begins when an action potential arrives at the neuromuscular junction. This triggers the release of the neurotransmitter acetylcholine from the motor neuron. Acetylcholine binds to receptors on the muscle cell membrane (sarcolemma), leading to depolarization. 2. **Release of Calcium Ions (A)**: The depolarization of the sarcolemma generates an action potential that travels along the T-tubules. This action potential stimulates the sarcoplasmic reticulum to release calcium ions into the sarcoplasm. 3. **Breakdown of ATP to Form a Cross Bridge (D)**: The released calcium ions bind to troponin, causing a conformational change that moves tropomyosin away from the actin binding sites. This allows myosin heads to attach to actin filaments. ATP is then broken down to ADP and inorganic phosphate, which provides the energy needed for the myosin heads to form cross bridges with actin. 4. **Sliding of Actin Filaments Over Each Other (C)**: Once the cross bridges are formed, the myosin heads pivot, pulling the actin filaments toward the center of the sarcomere. This sliding action leads to muscle contraction. Putting these steps in order, we have: - B: Release of Acetylcholine - A: Release of Calcium Ions - D: Breakdown of ATP to Form a Cross Bridge - C: Sliding of Actin Filaments Over Each Other Thus, the correct sequence is B, A, D, C. **Final Answer**: The correct sequence during muscle contraction is BADC.
Promotional Banner

Similar Questions

Explore conceptually related problems

The steps involved in the mechanism of muscle contraction are given below. Arrange the steps in proper sequential order and select the correct option. I. Release of calcium ions in the sarcoplasm. II. Signal sent by the CNS via a motor neuron. III. Binding of calcium with a subunit of troponin on actin filaments. IV. Generation of the action potential in the sarcolemma. V. Binding of myosin head to the exposed active sites on actin to form a cross-bridge. VI. Inward pulling of ‘Z’ line attached to actin causing shortening of the sarcomere. VII. Pulling of the attached actin filaments towards the centre of 'A' band. VIII. Release of neurotransmitter acetylcholine and generation of the action potential in the sarcolemma.

Go through the following statements During muscle contraction, the width of A-band remains constant while I-band shortens. During muscle contraction, the Ca^(2+) released from the SR bind to the troponin component of thin filament The process of muscle contraction is faster in smooth muscle as they have a well developed sarcoplasmic reticulum. The red muscle fibres have abundant mitochondria, low glycogen and poorly formed sarcoplasmic reticulum.

Assertion: on stimulation, a muscle cell releases calcium ions (Ca^(2+)) from sarcoplasmic reticulum. Reason: By reacting with a protien complex, Ca^(2+) uncover active sites on the actin filaments.

Given below are the steps involved in parturition. Arrange them in proper sequence and select the correct option. I. The induction of mild uterine contractions is called foetal ejection reflex. II. Stronger uterine contractions causing the further release of oxytocin. III. Origination of signals from the fully developed foetus and placenta. IV. Release of oxytocin from maternal pituitary V. Expulsion of baby from the birth canal (a) III , IV , I , II , V (b) III, I , IV , II , V (c) I, III , II , IV ,V (d) II , IV , III, I,V

Assertion :- Skeletal muscle fibre is synctium as the sarcoplasm contains many nuclei. Reason :- The sarcoplasmic reticulum of the muscle fibre is the store house of calcium ions. (a) If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion . (b) If both Assertion & Reason are True but Reason is not a correct explanation of the Assertion (c) If Assertion is True but the Reason is False. (d) If both Assertion & Reason are false.

Figure shows two block A and B , each having a mass of 320 g connected by a light string passing over a smooth light pulley. The horizontal surface on which the block A can slide is smooth. The block A is attached to spring constant 40 N//m whose other end is fixed to a support 40 cm above the horizontal surface. Initially, the spring is vertical and unstretched when the system is released to move. Find the velocity of the block A at the instant it breaks off the surface below it. Take g = 10 m//s^(2) .

Read the following statements regarding muscle contraction (i) One ATP utillised for making and breaking of the cross bridge. (ii) The sarcomere lies between 2 Z-lines (iii) Troponin blocks the active sites in resting stage (iv) Ca^(++) ions help in unmasking active sites on HMM Choose the correct option

Identify the wrong statements (a) The substrate binds to active site of enzyme and not fitting into active site (b) The binding of substrate induces the enzyme to alter its shape (c ) Chemical bonds of substrate break down not to form now enzyme product complex (d) The enzyme releases the products of the reaction and run through catalytic cycle once again