Science (English Medium) इयत्ता १२ - CBSE Question Bank Solutions for Biology

Answer the following question.
Why is there a fear amongst the guardians that their adolescent wards may get trapped in drug/alcohol abuse?

If a regular dose of drug or alcohol is not provided to an addicted person, he shows some withdrawal symptoms. List any four such withdrawal symptoms.

“Prevention is better than cure”. Comment.

Drugs and alcohol give short-term 'high' and long-term ‘damages’, Discuss.

Why do some adolescents start taking drugs. How can this be avoided?

In your locality, if a person is addicted to alcohol, what kind of behavioural changes do you observe in that person? Suggest measures to over come the problem.

What is apomixis?

How does a degenerate code differ from an unambiguous one?

Answer the following question.
Explain ‘addiction’ and dependence’ in respect of drug/alcohol abuse in youth.

Answer the following question.
Describe the structure and function of a t-RNA molecule. Why is it referred to as an adapter molecule?

Anticodon is an unpaired triplet of bases in an exposed position of ______.

Amino acid acceptor end of tRNA lies at ______.

Which RNA carries the amino acids from the amino acid pool to mRNA during protein synthesis?

The phenomenon observed in some plants wherein parts of the sexual apparatus are used for forming embryos without fertilization is called ______.

Are pollination and fertilization necessary in apomixis? Give reasons.

Are parthenocarpy and apomixis different phenomena? Discuss their benefits.

Assertion: Apomictic embryos are genetically identical to the parent plant.

Reason: Apomixis is the production of seeds without fertilization.

What is the importance of apomixis?

Which one of the following is a stop codon?

(a) UAG

(b) UAC

(c) AUG

(d) UCA

State what is apomixis. Comment on its significance. How can it be commercially used?