Organisms and Populations — BIOLOGY STD 12 Science — Question

Refer to the diagram given below and answer the questions that follows.

1. Label the parts A and B.
2. Which part of flower develops into seed and fruit?
3. What is the function of both the labeled parts?

Name and explain the surgical method advised to human males and females as a means of birth control. Mention its one advantage and one disadvantage.

Answer the following questions:
Name the organic material exine of the pollen grain is made up of. How is this material advantageous to pollen grain?

Rearrange Ramapithecus, Australopithecus and Homo habilis in the order of their evolution on the Earth. Comment on their evolutionary characteristics.

Explain the process of artificial hybridisation to get improved crop variety in:

1. Plants bearing bisexual flowers.
2. Female parent producing unisexual flowers.

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.

How is PCR technique beneficial in biotechnology? How are the developed countries related to biopiracy cases? Explain with an example.

What would happen if histones were to be mutated and made rich in acidic amino acids such as aspartic acid and glutamic acid in place of basic amino acids such as lysine and arginine?

Explain with the help of an example, each of the three population interactions, where the organisms live closely together.

A spermatogonial cell has 30 chromosomes. How many chromosomes will be found in:

1. The primary spermatocyte.
2. The spermatid?