A motor unit is best described as:

(1) All the nerve fibres and muscle fibres in a single muscle bundle

(2) One muscle fibre and its single nerve fibre

(3) A single motor neuron and all the muscle fibres that it innervates

(4) It is the neuron which carries the message from muscle to CNS

Subtopic:  Excitation Contraction Coupling I | Excitation Contraction Coupling II | Sliding Filament Theory |
 63%
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Electrical excitation in a muscle fibre most directly causes:

(1) Movement of tropomyosin

(2) Attachment of the cross bridges to actin

(3) Release of Ca+2 from sarcoplasmic reticulum

(4) Splitting of ATP

Subtopic:  Excitation Contraction Coupling I |
 80%
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The energy for muscle contraction is most directly obtained from:

(1) Phosphocreatine                          

(2) ATP

(3) Anaerobic respiration                   

(4) Aerobic respiration

Subtopic:  Energy for Muscle Contraction |
 81%
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Put the following phrases in proper order to describe what occurs at the neuromuscular junction to trigger muscle contraction:

I. Receptor sites on sarcolemma.
II. Nerve impulse.
III. Release of Ca+2 from sarcoplasmic reticulum
IV. The neurotransmitter acetylcholine is released
V. Sarcomere shorten
VI. Synaptic cleft
VII. Spread of impulses over sarcolemma on T-tubules


1. II, IV, I, VI, VII, III, V           

2. II, IV, VI, I, VII, III, V

3. I, II, III, IV, V, VI, VII             

4. VII, VI, V, IV, III, II, I

Subtopic:  Excitation Contraction Coupling I |
 64%
From NCERT
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Go through the following diagram describing muscle contraction:

Now identify A to E:
(1) A - Cross bridge, B - Cross bridge formation, C - Breaking of cross bridge, D - Sliding (rotation), E - ATP

(2) A - Cross bridge, B - Cross bridge formation, C - Sliding / rotation, D - Breaking of cross bridge, E - ATP

(3) A - Cross bridge, B - Breaking of Cross bridge, C - sliding / rotation, D - Cross bridge formation, E - AMP

(4) A - Cross bridge, B - Cross bridge formation, C - Sliding / rotation, D - ADP, E - Breaking of cross bridge

Subtopic:  Sliding Filament Theory |
 72%
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The muscle band that remains unchanged during muscle contraction and relaxation of the skeletal muscle is:

(1) I                     

(2) A                    

(3) H                    

(4) Z-line

Subtopic:  Skeletal Muscle: Sarcomere |
 89%
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The compound or pigment acting as an oxygen store in skeletal muscles is:

(1) Myoglobin                                    

(2) Haemoglobin

(3) Myokinase or ATP                         

(4) Cytochrome

Subtopic:  Muscle Contraction: Other Considerations |
 88%
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I. Number of mitochondria less.
II. Number of mitochondria more
III. Sarcoplasmic reticulum is abundant
IV. Myoglobin content high
V. Sarcoplasmic reticulum moderate
VI. Aerobic muscles
VII. Depend on anaerobic respiration for energy
VIII. Less myoglobin content
A. Red muscles B. White muscles
Identify above (I to VIII) traits as characteristic of A and B types of muscles:
(1) A - I, III, VII, VIII; B - II, IV, V, VI

(2) A - II, IV, V, VI; B - I, III, VII, VIII

(3) A - I, III, IV, VII; B - II, V, VI, VIII

(4) A - II, V, VI, VIII; B - I, III, IV, VII

Subtopic:  Muscle Contraction: Other Considerations |
 85%
From NCERT
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How many bones make up the human skeleton?

(1) 948                

(2) 96                            

(3) 796                

(4) 206

Subtopic:  Human Skeleton: Introduction, Function, Parts |
 98%
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Number of bones in human axial skeleton is:

(1) 80                            

(2) 106                

(3) 206                

(4) None of these

Subtopic:  Number of Bone in Axial Skeleton |
 91%
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