Q. No.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
1. (i), (iii), (iv) and (v) 2. (i), (ii) and (v) 3. (ii), (iv) and (v) 4. (i), (ii) and (iii)
(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
Which of the following is true for the labelled parts in the figure below?
1. A - Z-line - located at centre of I - band
2. B - Thin filament - occurs in A-band only
3. C - Thick filament - confined to I-band
4. D - H-zone - located at centre of M-line
The H-Zone in the skeletal muscle fibre is due to
1. the central gap between actin filaments extending through myosin filaments in the A-band
2. extension of myosin filaments in the central portion of the A-band
3. the absence of myofibrils in the central portion of A-band
4. the central gap between myosin filaments in the A-band
An example of stretch reflex triggered by passive muscle movement is the
1. tendon reflex
2. ipsilateral reflex
3. flexor reflex
4. patellar reflex
In old age, stiffness of joints is due to the
1. hardening of bones
2. inefficiency of muscles
3. decrease in synovial fluid
4. enlargement of bones
Skeletal muscles appear striated due to presence of two characteristic proteins in alternating dark and light bands. Which of the following is a correct match of the protein with its light refractive property and colour?
| Protein | Colour | Property | |
| 1. | Myosin | Light | Anisotropic |
| 2. | Actin | Dark | Anisotropic |
| 3. | Myosin | Dark | Isotropic |
| 4. | Actin | Light | Isotropic |
Which one of the following item gives its correct total number?
1. Floating ribs in humans - 4
2. Amino acids found in proteins -16
3. Types of diabetes - 3
4. Cervical vertebrae in humans - 8
Sliding filament theory can be best explained as
1. when myofilaments slide pass each other, actin filaments shorten while myosin filaments do not shorten
2. actin and myosin filaments shorten and slide pass each other
3. actin and myosin filaments do not shorten but rather slide pass each other
4. when myofilaments slide pass each other, myosin filaments shorten while actin filaments do not shorten
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R):
| Assertion (A): | Osteoporosis is common in post-menopausal women. |
| Reason (R): | The small intestine in post-menopausal women is unable to absorb divalent cations such as calcium. |
In the light of the above statements choose the correct answer from the options given below:
| 1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
| 3. | (A) is true but (R) is false. |
| 4. | Both (A) and (R) are false. |
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