Tag: muscle contraction

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Questions Related to muscle contraction

Multiple choice biology movement in animals types of muscles muscles muscles and their structure muscle contraction

In muscle fibres, the endoplasmic reticulum.

  1. Is known as sarcoplasmic reticulum

  2. Is poorly developed

  3. Is irregularly shaped

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  1. sarcoplasmic reticulum is a specialized type of smooth ER that regulates the calcium ion concentration in the cytoplasm of striated muscle cells. 
  3. sarcoplasmic reticulum  is a membrane-bound structure found within muscle is also known as endoplasmic reticulum of muscle. so option A is correct answer .
Multiple choice biology movement in animals types of muscles muscles muscles and their structure muscle contraction

Sarcomere is the functional unit of

  1. Contraction

  2. Relaxation

  3. Contraction and relaxation

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • The ‘A’ and ‘I’ bands are arranged alternately throughout the length of the myofibrils.
  • In the centre of each ‘I’ band, there is an elastic fibre called ‘Z’ line which bisects it. The thin filaments are firmly attached to the ‘Z’ line. 
  • The portion of the myofibril between two successive ‘Z’ lines is considered as the functional unit of contraction and is called sarcomere.
  • Hence Sarcomere is the unit of contraction.
Multiple choice biology movement in animals types of muscles muscles muscles and their structure muscle contraction

Total number of muscles in human body comes in the range of

  1. 440-550

  2. 640-850

  3. 1150-1500

  4. More than 2000
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • Muscle is a  bundle of fibrous tissue in a body that has the ability to contract, producing movement in or maintaining the position of parts of the body.
  • The total number of muscles in the human body comes in the range of 640-850.
  • So,the correct answer is '640-850'
Multiple choice biology movement in animals types of muscles muscles muscles and their structure muscle contraction

Condition of having a number of nuclei in a muscle fibre is

  1. Polykaryon

  2. Coenocytic

  3. Syncytial

  4. Endoduplication
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

  •  Syncytial or syncytium is a multinucleated cell that can result from multiple cell fusions of uninuclear cells (i.e., cells with a single nucleus), which can result from multiple nuclear divisions without accompanying cytokinesis. 
  • Syncytial is also referring to cells interconnected by the specialized membrane with gap junctions, as seen in the heart muscle cells and certain smooth muscle cells, which are synchronized electrically in an action potential. Hence, Condition of having a number of nuclei in a muscle fibre is syncytial.
So, the correct answer is 'syncytial'.

Multiple choice biology locomotion and movement locomotion in animals bones and movements muscle contraction types of muscles muscles

Upon stimulation of skeletal muscles, calcium is immediately made available for binding to troponin from :

  1. Blood

  2. Lymph

  3. Sacroplasmic reticulum

  4. Bone
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Answer is option C i.e. "Sacroplasmic reticulum"
Neurotransmitter acetylcholine generates an action potential in the sarcolemma causing the release of calcium ions into the sarcoplasm from the sarcoplasmic reticulum.
When Ca++ level increases it leads to the binding of calcium with a sub-unit of troponin on actin(thin) filaments and thereby activating the movement.

Multiple choice biology locomotion and movement locomotion in animals bones and movements muscle contraction types of muscles muscles

An iron-containing protein myoglobin is present in the

  1. Spleen

  2. Lungs

  3. Muscles

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Myoglobin is the iron and oxygen-binding protein that is found in the muscle tissue of the vertebrates and in almost all mammals. This contains heme, the pigment responsible for the red color of meat.

Therefore, the correct answer is option C.

Multiple choice biology locomotion and movement locomotion in animals bones and movements muscle contraction types of muscles muscles

What would be the result of an allele that codes for all actin molecules to be synthesized in linear chains?

  1. Immovable muscles

  2. Smooth muscle tissue

  3. Normal sarcomere structure

  4. Degeneration of muscle tissue

  5. Muscle tendons that cannot attach
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Sarcomere is the structural and functional unit of a myofibril and consists of thick myosin filaments and thin actin filaments. If the allele for actin filament continues to synthesize linear chains of the protein, sarcomere structure would be same as normal. Thus, the correct answer is option C.

Multiple choice biology locomotion and movement locomotion in animals bones and movements muscle contraction types of muscles muscles

Which of the following is the result of synthesis of actin molecule(coded by allele) in a linear chain?

  1. Immovable muscles

  2. Smooth muscle tissue

  3. Normal sarcomere structure

  4. Degeneration of muscle tissue

  5. Muscle tendons that cannot attach
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • A sarcomere is the functional unit (contractile unit) of a muscle fibre. 
  • Each sarcomere contains two types of myofilaments: thick filaments, composed primarily of the contractile protein myosin, and thin filaments, composed primarily of the contractile protein actin. Hence, Normal sarcomere structure is the result of the synthesis of actin molecule(coded by allele) in a linear chain.
So, the correct answer is 'Normal sarcomere structure'.
 
Multiple choice biology locomotion and movement locomotion in animals bones and movements muscle contraction types of muscles muscles

The binding of troponin to calcium in muscle cells exposes the binding site of

  1. Tropomyosin

  2. Myosin

  3. ATP

  4. ADP
  5. ${P} _{i}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

  • Muscle contraction thus results from an interaction between the actin and myosin filaments that generates their movement relative to one another. 
  • The molecular basis for this interaction is the binding of myosin to actin filaments, allowing myosin to function as a motor that drives filament sliding. Hence, The binding of troponin to calcium in muscle cells exposes the binding site of Myosin.
So, the correct answer is 'Myosin'.