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IMPORTANT
Earn 100
The given figure shows an actin (thin) filament. Identify the labelled parts A, B and C and select the correct option.
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Important Questions on Locomotion and Movement
MEDIUM
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IMPORTANT
Fill up the blanks in the following sentence by selecting the correct option.
The thin filaments of myofibril contain __(i)__ actin and two filaments of __(ii)__ protein along with __(iii)__ protein for masking binding site for myosin.
| (i) | (ii) | (iii) | |
|---|---|---|---|
| (a) | 1F | troponin | tropomyosin |
| (b) | 1F | tropomyosin | troponin |
| (c) | 2F | troponin | tropomyosin |
| (d) | 2F | tropomyosin | troponin |
MEDIUM
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IMPORTANT
Actin binding sites are located on
MEDIUM
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IMPORTANT
The given figure is related to the myosin monomer (meromyosin). Identify the parts labelled from A to C and select the correct option.
MEDIUM
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IMPORTANT
Which of the following statements are correct regarding muscle proteins?
(i) Actin is a thin filament and is made up of two F-actins
(ii) The complex protein, tropomyosin is distributed at regular intervals on the troponin
(iii) Myosin is a thick filament which is also a polymerised protein
(iv) The globular head of meromyosin consists of light meromyosin (LMM)
MEDIUM
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IMPORTANT
Which of the following statements about the molecular arrangement of actin and myosin in myofibrils is/are incorrect?
(i) Each actin (thin filament) is made of 2F (filamentous) actins.
(ii) F-actin is the polymer of G (globular) actin.
(iii) 2F-actins are twisted into a helix.
(iv) Two strands of tropomyosin (protein) lie in the grooves of F-actin.
(v) Troponin molecules (complex proteins) are distributed at regular intervals on the tropomyosin.
(vi) Troponin forms the head of the myosin molecule.
(vii) The myosin is a polymerised protein.
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Which one of the following options shows the next stage of muscle contraction after the stage given in question?
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During muscular contraction, which of the following events occur?
(i) H-zone disappears
(ii) A-band widens
(iii) I-band reduces in width
(iv) Width of A-band is unaffected
(v) M-line and Z-line come closer
MEDIUM
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IMPORTANT
The figures given here represent three different conditions of sarcomeres. Identify these conditions and select the correct option.
| A | B | C | |
|---|---|---|---|
| (i) | Contracting | Relaxed | Maximally contracted |
| (ii) | Relaxed | Contracting | Maximally contracted |
| (iii) | Maximally contracted | Contracting | Relaxed |
| (iv) | Relaxed | Contracted | Contracting |
