Multiple Choice Questions

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Assertion : Hormone calcitonin has antagonistic effect to that of parathormone.

Reason : Calcitonin decreases blood calcium level while parathormone increases blood calcium level.

  • 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


A.

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

Calcitonin or thyrocalcitonin is secreted by parafollicular cells of thyroid stroma. It retards bone dissolution and stimulates excretion of calcium in urine. Thus, it lowers calcium level in extra cellular fluid (ECF).

Parathornone is secreted by chief cells of parathyroid gland and is also known as Collip's hormone. It maintains blood calcium level by increasing its absorption from food in intestine and its reabsorption from nephrons in the kidney. Maintenance of proper calcium level is in fact, a combined function of parathormone and calcitonin. When calcium level falls below normal, then parathormone maintains it by promoting its absorption, reabsorption and also by demineralization of bones. When blood calcium level exceeds above normal, then calcitonin hormonen increases excretion of calcium in urine.


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National bird of India is

  • Psittacula

  • Passer domesticus

  • Pavo cristatus

  • Parakeet


Specific proteins responsible for the flow of materials and information into the cell are called

  • membrane receptors

  • carrier proteins

  • integral proteins

  • none of these


Assertion : Connective tissue inside the brain is essential for conduction of nerve impulse.

Reason : Connective tissue hold together the nerve cells of brain.

  • 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


Assertion: Cytokinins increases shelf life of fruits and vegetables.

Reason : Cytokinins induce cell division.

  • 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


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Assertion : Angina pectoris means "pain in the chest".

Reason : It results due to carrying of extra blood to the heart muscle.

  • 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


Assertion : Glycolysis is the first step of respiration in which glucose completely breaks into CO2 and H2O.

Reason : In this process, there is net gain of twenty four molecules of ATP.

  • 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


Assertion : Excess of nitrates in drinking water are harmful for infants.

Reason : Nitrates are responsible for blue baby syndrome.

  • 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


Assertion : Nucleus is the controlling centre of a cell.

Reason : Pores in the nuclear envelop regulate the flow of materials in and out of the nucleus.

  • 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


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Assertion : Dark reaction occurs only at night in the stroma of chloroplast.

Reason : CO2 fixation occurs only during C3 cycle.

  • 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