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

Observe the relationship between first two words and suggest suitable word for the fourth one:

1. Ovary : Mesovarium :: Uterus: A.
2. Male : Penis :: Female : B.
3. Male gametes: Sperms:: Female gametes: C.

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

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

What is the role of transgenic animals in biological product?

How does Agrobacterium tumefaciens act as a suitable vector in biotechnology experiments? Cite an example, where it has been successfully used as a vector.

When do the oogenesis and the spermatogenesis initiate in human females and males respectively?

1. Why is human ABO blood group gene considered a good example of multiple alleles?
2. Work out a cross up to F1 generation only, between a mother with blood group B (Homozygous). Explain the pattern of inheritance exhibited.

Differentiate between two different types of pyramids of biomass with the help of one example of each.

1. Name any four vegetative propagules along with their examples.
2. What are the various natural methods of vegetative propagation?

1. Sickel-cell anaemia in humans is a result of point mutation. Explain.
2. Write the genotypes of both the parents who have produced a sickle-cell anaemic offspring.

The length of a DNA molecule in a typical mammalian cell is calculated to be approximately 2.2m. How is the packaging of this long molecule done to accommodate it within the nucleus of the cell?