NEET-UG Biology · Class 11
What happens during a contraction — NEET & JEE Questions
What happens during a contraction is a topic in Locomotion and Movement, a Class 11 Biology chapter of the NEET-UG syllabus. TestBudy holds 21 published NEET-UG questions on What happens during a contraction, each with the marking scheme of the real paper. The ideas it examines include How calcium uncovers the binding sites, Where ATP is used in the cross bridge cycle, Which bands shorten when a muscle contracts.
- questions
- 21
- shown here
- 10
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Key formulas and concepts
The ideas What happens during a contraction is examined on, as they are tagged in the syllabus tree.
- How calcium uncovers the binding sites
- Where ATP is used in the cross bridge cycle
- Which bands shorten when a muscle contracts
What happens during a contraction MCQs with solutions
10 of the 21 published questions on this topic, exactly as they appear in a test. Answers and worked solutions come with your result rather than on this page.
During contraction the H zone generally:
- A. narrows or may disappear
- B. widens
- C. becomes a Z line
- D. remains always unchanged
During contraction the I band generally:
- A. shortens
- B. becomes the A band
- C. remains exactly unchanged
- D. lengthens
During contraction the length of the A band:
- A. doubles
- B. disappears
- C. remains essentially constant
- D. shortens to zero
The ion that binds troponin to initiate skeletal-muscle contraction:
- A. chloride
- B. iron
- C. sodium
- D. calcium
According to the sliding filament theory, what happens to actin and myosin filaments during contraction?
- A. Both filaments become much shorter
- B. They slide past one another without substantially changing their own lengths
- C. Only myosin filaments disappear
- D. Actin is converted into myosin
What is the immediate role of calcium ions in initiating skeletal muscle contraction?
- A. They replace ATP on the myosin head
- B. They break down actin filaments
- C. They bind to troponin and shift tropomyosin away from actin's myosin-binding sites
- D. They directly shorten the Z lines
What happens when ATP binds to a myosin head that is attached to actin?
- A. Actin is hydrolysed
- B. The Z lines move farther apart permanently
- C. Calcium is released from troponin
- D. The myosin head detaches from actin
During skeletal-muscle contraction, calcium ions bind mainly to
- A. troponin
- B. myosin heavy chain only
- C. actin's ATPase site
- D. collagen
During contraction, which sarcomere change is expected?
- A. The I band and H zone become narrower while the A band remains constant
- B. The A band shortens while the I band remains constant
- C. All bands lengthen equally
- D. The Z lines move farther apart
A muscle fibre is stimulated but calcium cannot be released into the sarcoplasm. Which event is most directly blocked?
- A. ATP production by mitochondria
- B. Exposure of myosin-binding sites on actin
- C. Formation of thick myosin filaments
- D. Generation of the action potential in the motor neuron
Common mistakes in What happens during a contraction
Recorded against questions in this topic that are not shown above, so none of these points at an answer you can see on this page.
- Equating shortening of the sarcomere with shortening of the protein filaments.
- Assumes muscle contraction begins by shortening the actin filament itself.
- Reverses the direction of filament sliding.
- Assumes ATP alone is sufficient to trigger contraction without calcium regulation.
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