Biology Mcqs

Collagen fibers of bone are hardened by deposition of_____________?

A. Ca & PO4
B. CaCO3
C. CaSO4
D. SiO2

Tetany is caused by__________?

A. Hypocalcemia
B. Hypercalcemia
C. Clostridum tetani.
D. Low O2 level

Which of the following statement about fatigue is correct?

A. The major event in it is accumulation of lactic acid.
B. Lactic acid accumulation turns pH in acidic range leading to muscle ache.
C. Ionic imbalance may also cause it.
D. All of these

Endoskeleton is secreted by?

A. Ectoderm.
B. Endoderm.
C. Mesoderm.
D. All of these

Ecdysone is_________________?

A. An enzyme that digest endocuticle during an arthropodal ecdysis
B. A newly formed exoskeleton in authropods
C. A hormone that regulates moulting in arthropods
D. A process that involves moulting

Which of the following statement about an arthropod exoskeleton is incorrect?

A. It permits gaseous exchange
B. It contains joints, for the same purpose as present in human skeletal system
C. It provides muscle attachment
D. Like all the other types of exoskeleton, they lack sensation

Rigor mortis i.e, stiffening of body after death results from__________?

A. Accunulation of rigid proteins molecules in sarcoplam.
B. Unavailability of ATP, which is necessary to break the link between actin and myosin.
C. Decrease in body temperature after death.
D. Death of tissue due to unavailability of O2.

Exoskeleton of a marine snail is composed of________________?

A. CaPO4
B. CaCO3
C. CaSO4
D. SiO2

Which of the following step occurs immediately after binding of Ca2+ with troponin molecule during muscle contraction.

A. Binding sites of actin get attached to the myosin head.
B. Troponin uncovers the actin binding sites.
C. Tropomyosin gets removed from the binding sites of actin filaments.
D. Ca2+ goes back inside sarcoplasmic reticulum.

What happens during muscle contraction to the length of each myosin and action filament?

A. Z- lines get closer
B. A band becomes short
C. 1 band elongates
D. There is no change in sarcomere