Question Bank [2022] — BIOLOGY STD 12 Science — Question

What is the basic principle of vaccination? How do vaccines prevent microbial infections? Name the organism from which hepatitis B vaccine is produced.

The generative cell of a 2-celled pollen divides in the pollen tube but not in a 3-celled pollen. Give reasons.

The base sequence in one of the strands of DNA is TAGCATGAT

1. Give the base sequence of its complementary strand.
2. How are these base pairs held together in a DNA molecule?
3. Explain the base complementarity rules. Name the scientist who framed this rule.

Explain the significance of satellite DNA in DNA fingerprinting technique.

Why is predation important and required in a community with rich biodiversity? Explain with the help of suitable examples.
OR
What is 'predation"? Explain with the help of suitable examples, why it is required in a community with rich biodiversity.

Eco RI is used to cut a segment of foreign DNA and that of a vector DNA to form a recombinant DNA. Show with the help of schematic diagrams.

1. The set of palindronic nucleotide sequence of base pairs the Eco RI will recognise in both the DNA segments. Mark the site at which Eco RI will act and cut both the segments.
2. Sticky ends formed on both the segments where the two DNA segments will join later to form a recombinant DNA.

What is Jhum cultivation?

Explain three main functions of free antibodies produced by B-lymphocytes.

1. Name the organism in which the vector shown is inserted to get the copies of the desired gene.
2. Mention the area labelled in the vector responsible for controlling the copy number of the inserted gene.
3. Name and explain the role of a selectable marker in the vector shown.

Answer the following question.
What are the goals of RCH programme.