Home
Class 12
BIOLOGY
Assertion : Nucleus is the controlling c...

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.

A

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

B

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

C

If assertion is true but reason is false

D

If both assertion and reason are false.

Text Solution

Verified by Experts

The correct Answer is:
B
Nucleus is the controlling centre of a ceil 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.
Doubtnut Promotions Banner Mobile Dark
|

Similar Questions

Explore conceptually related problems

Nucleus is known as brain of the cell. Give reason for your answer.

Assertion (A): Nucleus is not located in the centre of a plant cell unlike an animal cell. Reason (R ): Plant cells possess chloroplasts that are not present in an animal cell.

Knowledge Check

  • The flow of molecules in and out of a cell is regulated by

    A
    cell membrane
    B
    mitochondria
    C
    golgi body
    D
    nucleus

  • Assertion. Nucleus controls metabolism as well as heredity. Reason. There is usually a single nucleus in a cell.

    A
    If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
    B
    If both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
    C
    If Assertion is true but Reason is false.
    D
    If both Assertion and Reason are false.

  • Assertion: Nucleus controls the metabolic activitie of cytoplasm. Reason: Nucleus synthesizes enzymes and send them to cytoplasm to control the activities.

    A
    If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion.
    B
    If both Assertion & Reason are True but Reason is not a correct explanation of the Assertion.
    C
    If Assertion is True but the Reason is False.
    D
    If both Assertion & Reason are false.

    • Similar Questions

    Explore conceptually related problems

    Assertion (A) : Nucleus of the atom does not contain electrons, yet it emits beta- particles in the form of electrons. Reason (R): In the nucleus , protons and neutrons exchange mesons frequently.

    Assertion :- Morphology of chromosomes is most studied during metaphase of cell division. Reason :- Complete disintegration of nuclear envelope marks the start of metaphase, second phase of mitosis.

    Assertion (A) : Nucleus of the atom does not contain electrons,yet it ewmits beta -particles in the form electrons Reason (R ) : In the nucleus, protons and neutrons exchange mesons frequently

    Assertion :- Nucleus is the organised structure remains surrounded by continuous membrane. Reason:- Nuclear membrane is permeable so no need of discontinuities.

    Read the statements below regarding the nucleus of a cell. Identify them as true or false and select the correct combination option. I. The nucleus displays an elaborate nucleoprotein fiber called chromatin during the interphase of the cell cycle. II. The space between the parallel membranes of the nuclear envelope is called the nucleoplasm. III. Nucleus was discovered first by Flemming. IV. The nuclear pores within the nuclear envelope are formed by the fusion of both membranes. {:("No.",I,II,III,IV),(1,"True","True","False","False"),(2,"True","False","False","False"),(3,"True","True","False","False"),(4,"True","False","False","True"):}

    Home
    Profile