Multiple Choice Questions

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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


B.

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

Nucleus is the controlling centre of a cell as it contains chromosomes and genes. Chromosomes contain the DNA which by transcription prepare RNA which in turn leads to the formation of proteins by translation. These proteins regulate the various metabolic processes going in the cell. Besides this, nucleus contains genetic information for reproduction, development & behaviour of an organism.

Nuclear membrane is double layered, semipermeable and is perforated by minute, circular nuclear pores. The pore controls the passage of macromolecules like tRNAs, mRNAs, ribosomal proteins, enzymes etc. during different processes of transcription, translation etc.


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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 : 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


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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