AIIMS 2009
- Exam
- AIIMS
- Year
- 2009
- Subject
- Botany
- Chapter
- Cell - The Unit of Life
AIIMS 2009 · Botany · Cell - The Unit of Life
Assertion : Nucleus is the controlling centre of a cell. Reason:...
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.
Options
- AIf both assertion and reason are true and reason is the correct explanation of assertion
- BIf both assertion and reason are true but reason is not the correct explanation of assertion
- CIf assertion is true but reason is false
- DIf both assertion and reason are false.
Correct answer
B. If both assertion and reason are true but reason is not the correct explanation of assertion
Step-by-step solution
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.