Question

Nucleus is the controlling centre of a cell. 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

Answer 1

Answer: (B)

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

Answer 2

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. Nuc l e a r membr ane i s doubl e l aye r ed, 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.