Biology Mcqs

Which one of the following forms the blk of exoskeleton of an arthropod?

A. Epicuticle
B. Procuticle
C. Ectocuticle
D. None of these

If a cross section of a sarcomere is seen, each myosin is surrounded by how many actin molecules:

A. 9
B. 5
C. 6
D. 7

Which of the following statement is incorrect about Molluscans?

A. They are surrounded by single or double pieces of hard skeleton.
B. Their shell grows as the animal grows.
C. They have hydrostatic skeleton.
D. They move by tube feet

The most important function of troponin is___________?

A. To bind with actin
B. To bind with tropomyosin.
C. To bind with Ca2+ ions.
D. All of these

In an annelids, the contraction of circular muscle results in___________?

A. Lengthening of the body.
B. Shortening of the body.
C. Widening of body
D. Thinning of body

Which of the following animal has a hydrostatic skeleton?

A. Earthworm
B. Round worm
C. Tape worm
D. worm

A smallest contractile unit of muscle contraction called sarcomere is the area between two:

A. H- zone
B. M- Line
C. Z- Line
D. A band

Gibberellins is an example of_________________?

A. Growth inhibitor
B. Growth stimulator
C. Growth hormone
D. None of these

Which of the following statements is incorrect about skeletal muscle fibers?

A. They are multinucleated.
B. They are 10 – 100 ?m in diameter & surrounded by sarcolemma
C. They contain O2 storing molecules called hemoglobin.
D. Their cytoplasm contains high concentration of carbohydrates

Easty is controlled by_____________?

A. Gibberellins
B. Abscisins
C. Auxins
D. Cytokinins