Biotechnology: Principles and Processes — BIOLOGY STD 12 Science — Question

With the help of a diagram explain the structure of DNA.

Explain the surgical method of contraception with the help of a labelled diagram.###Write the name of a surgical contraceptive method and explain it which can be adopted by the male member of the couple.

Enumerate the different measures for control and prevention of drug/ alcohol abuse among adolescent.

Why are colour blindness and thalassemia categorised as Mendelian disorders? Write the symptoms of these diseases seen in people suffering from them.

Describe in detail the human reproductive system.

Describe the structure of a young anther as seen in a transverse section.

You have studied the story of Pepper moths in England. Had the industries been removed, what impact could it have on the moth population? Discuss.

Explain with the help of one example how genetically modified plants can:

1. Reduce usage of chemical pesticides.
2. Enhance nutritional value of food crops.

1. Explain the role of regulatory gene, operator, promoter and structural genes in lac operon, when E.coli is growing in a culture medium with the source of energy as lactose.
2. Mention what would happen, if lactose is withdrawn from the culture medium.

OR

Describe how the lac operon operates both in the presence and absence of an inducer in E.coli.

There is only one possible sequence of amino acids when deduced from a given nucleotide. But multiple nucleotide sequences can be deduced from a single amino acid sequence. Explain this phenomenon.