Plant Growth and Mineral Nutrition — BIOLOGY STD 12 Science — Question

Write a brief account of releasing factors secreted by hypothalamus.

Although sexual reproduction is a long drawn, energy-intensive complex form of reproduction, many groups of organisms in Kingdom Animalia and Plantae prefer this mode of reproduction. Give atleast three reasons for this.

Asexual reproduction and Sexual reproduction.

Any recombinant DNA with desired gene is required in billion copies for commercial use. How is this amplification done? Explain.

1. Work out a dihybrid cross upto F, generation between pea plants bearing violet-coloured axial flowers and white-coloured terminal flowers. Give their phenotypic ratio.
2. State the Mendel's law of inheritance that was derived from such a cross.

Complete the following table

Action	Reflex	Voluntary
1. Optic nerve	———–	———–
2. Facial	———–	————
3. Hypoglossal	————	————–
4. Trigeminal	———–	————
5. Auditory
6. Glosso-pharyngeal

How would you explain inverted pyramid of biomass in oceanic ecosystem?

A group of scientists is working on creating transgenic cows to produce milk with medicinal properties. But there are adverse side effects seen on the cows due to this procedure. Their lifespan shortened; they became prone to diseases and died very early.

1. What do you mean by transgenic animals?
2. Should the scientists continue with the production of transgenic cows? Give reason.
3. Is there any law to regulate such acts?
4. What values did scientists lack?

Describe the difference between the structures of a dicot embryo and monocot embryo. Also draw LS of monocot and dicot seeds.

Distinguish between : External respiration and Internal respiration.