Reproduction in organisms — BIOLOGY STD 12 Science — Question

Name the group of bacteria involved in setting milk into curd. Explain the process they carry in doing so. Write another beneficial role of such bacteria.

What will be the phenotype of progeny, if a carrier haemophilic female marries a normal male? Explain

How has RNAi technique helped to prevent the infestation of roots in tobacco plants by a nematode Meloidogyne incognita?

Explain two ways of 'improper resource utilization' that can cause degradation of natural resources.

In a sea shore, the benthic animals live in sandy, muddy and rocky substrata and accordingly developed the following adaptations.

1. Burrowing.
2. Building cubes.
3. Holdfasts/ peduncle.

Find the suitable substratum against each adaptation.

Which are silent areas of the brain?

Differentiate between the following:Repetitive DNA and Satellite DNA.

1. What are meiocytes?
2. If the chromosome number in meiocytes of human beings, housefly, potato, apple, dog and maize are 46, 12, 48, 34,78 and 20, respectively. What will be the chromosome numbers in gametes of these species?

The following graph represents the organismic response to certain environmental condition (e.g., temperature):

1. Which one of these, ‘a’ or ‘b’, depicts conformers?
2. What does the other line graph depict?
3. How do these organisms differ from each other with reference to homoeostasis?
4. Mention the category to which humans belong.

Types of nerves
Occulomotor, Facial, Optic, Vagus, Abducens, Vestibulocochlear

Column A	Column B
(1) Sensory	————–
(2) Motor	————–
(3) Mixed	————–