Reproduction in organisms — BIOLOGY STD 12 Science — Question

Draw and label the enlarged view of microsporangium of an Angiosperm. State the function of its innermost wall layer.

How do genes and chromosomes share similarity from the point of view of genetical studies?

Double fertilisation is reported in plants of both, castor and groundnut. However, the mature seeds of groundnut are non-albuminous and castor are albuminous. Explain the post-fertilisation events that are responsible for it.

Read the graph given above showing the levels of ovarian hormones during menstruation and correlate the uterine events that take place according to the hormonal levels on:

1. 6-15 days.
2. 16-25 days.
3. 26-28 days (if the ovum is not fertilised) .

1. Draw schematic diagrams of segments of a vector and a foreign DNA with the sequence of nucleotides recognised by EcoRI.
2. Draw the vector DNA segment and foreign DNA segment after the action of EcoRI and label the sticky ends produced.

Name the special type of tissue enabling plants like lotus and water hyacinth to survive in aquatic environment. Mention any two specific functions of this tissue?

Biotechnology has helped farmers to get pest resistant cotton crops. Explain the technique adopted along with its mode of action. (Mention six points).

A plasmid DNA and a linear DNA (both of the same size) have one site for a restriction endonuclease. When cut and separated on agarose gel electrophoresis, plasmid shows one DNA band while linear DNA shows two fragments. Explain.

Identify A, B, C, D and E given in sketch of carbon cycle

Azospirillumas as a biofertilizer