DIFFERENCES BETWEEN MYOSIN AND ACTIN FILAMENTS
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Myosin filaments (primary filaments)
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Actinfilaments (secondary filaments)
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1.
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Found only in A-band of sarcomere.
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1.
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Found in both A and I-bands.
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2.
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Thicker (0.01 mm) but longer (4.5 mm) than actin filaments.
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2.
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Thinner (0.005 mm) but shorter (2-2.6 mm)
than myosin filaments.
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3.
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More molecular weight.
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3.
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Less, molecular weight.
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4.
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Cross bridges present, hence have rough
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4.
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Cross bridges absent, hence have smooth
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surface.
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surface.
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5.
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Fewer than actin filaments.
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5.
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More numerous than myosin filaments, six of
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6.
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Free at both the ends.
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6.
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them surround each myosin filament.
Free at one end and are joined to Z-line by other end.
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7.
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Consist of 2 proteins: myosin and meromysm.
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7.
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Consist of 3 proteins: actin, tropomyosin and troponin.
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8.
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Do not slide during muscle contraction.
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8.
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Slide into H-zone during muscle contraction.
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