Sexual Reproduction In Flowering Plants — BIOLOGY STD 12 Science — Question

What is the meaning of sterilisation? Why is it essential in tissue culture?

Do haploid organisms undergo meiosis in their life cycle? If yes, state when does it occur.

What will be the effect on ova if oviducts in female are replaced by plastic tubes?

What is the fate of trophoblast in mammalian embryo?

In a cross between two tall pea plants, some of the offsprings produced were dwarf. Show with the help of Punnet square, how this is possible.

Write the functions of:

1. cry IAc gene.
2. RNA interference (RNAI).

State how has Agrobacterium tumifaciens been made a useful cloning vector to transfer DNA to plant cells.

In peas, tallness is dominant over dwarfness, and red colour of flowers is dominant over the white colour. When a tall plant bearing red flowers was pollinated by a dwarf plant bearing white flowers, the different phenotypic groups were obtained in the progeny.
Tall, Red = 138
Tall, White = 132
Dwarf, Red = 136
Dwarf, White= 128
Mention the genotypes of the two parents and of the types of four off springs. in numbers mentioned against them.

Mention the three zones of a biosphere reserve.

Study the schematic representation of evolutionary history of plant forms given below and mention

1. The plant forms ferns and conifers are most related to.
2. The nearest ancestors of flowering plants.
3. The most primitive group of plants.
4. Common ancestry of Psilophyton provides to.
5. The common ancestor of Psilophyton and seed ferns.
6. The common ancestors of mosses and tracheophytes.