The thin filaments of a muscle fibre are made up of

• actin, troponin, tropomyosin

• actin, troponin

• myosin, troponin

• actin, tropomyosin

Which one of the following is not a mammalian character?

• Presence of milk producing glands

• Skin is unique in possessing hair

• Presence of external ears called pinnae

• Homodont type of dentition

Which of the following pairs is correctly matched?

• Cartilaginous joint - Skull bones

• Hinge joint - Between vertebrae

• Fibrous joint - Between phalanges

• Gliding joint - Between zygapophyses of the successive vertebrae

Assertion: On stimulation, a muscle cell releases calcium ions (Ca²⁺) from sarcoplasmic
reticulum.

Reason: By reacting with a protein complex, Ca uncover active sites on the actin filaments

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

Achondroplasia is a disease related with the defect in the formation of

• membrane

• cartilage

• mucosa

• none of these

Total number of bones in the hind limb of a man is

• 21

• 23

• 27

• 30

An example of stretch reflex triggered by passive muscle movement is the

• tendon reflex

• ipsilateral reflex

• flexor reflex

• patellar reflex

Which of the following is a transparent tissue

• Tendon

• Hyaline cartilage

• Fibrous cartilage

• All of these

The H-zone in the skeletal muscle fibre is due to

• the central gap between actin filaments extending through myosin filaments in the A-band

• extension of myosin filaments in the central portion ofthe A-band

• the absence of myofibrils in the central portion of A-band

• the central gap between myosin filaments in the A-band.

Select the correct option regarding A, B and C.

• A-Tropomyosin-runs close to F-actin throughout its length

• B-Troponin-complex protein distributed at regular interval of tropomyosin

• C-F actin-polymer of monomeric G-actin helically bound to each other

• None of these