Biodiversity and Conservation — BIOLOGY STD 12 Science — Question

Describe any three potential applications of genetically modified plants.

Write three example of mendelian disorders and explain any one of them.

In the figure given below label the following parts: male gametes, egg cell, polar nuclei, synergid and pollen tube,

Write a short note on advantages of seeds.

To which category of cells do B-cells and T-cells belong? How do they differ from each other with reference to their formation and response to antigens?

A student was simulating Urey and Millers experiment to prove the origin of life. The set up used by the student is given.

1. Find out the reasons why he could not get desired results.
2. What conclusion was drawn by Urey and Miller through this experiment?
3. Compare the conclusion drawn with the theory of spontaneous generation.

For flower colour in pea, the allele for purple flower (P) is dominant to the allele for white flower (p). A purple flowered plant therefore could be of genotype PP or Pp. What genetic cross would you make to determine the genotype of a purple flowered plant? Explain how your cross gives you the correct genotype of the purple flowered plant?

Water is very essential for life. Write any three features both for plants and animals which enable them to survive in water scarce environment.

The following graph shows the species-area relationship. Answer the following question as directed.

1. Name the naturalist who studied the kind of relationship shown in the graph. Write the observation made by him.
2. Write the situations as discovered by the ecologists when the value of 'Z' (slope of the line) lies.

1. 0.1 and 0.2
2. 0.6 and 1.2

What does 'Z' stand for?

3. When would the slope of the line 'b' become steeper?

What type of organs eye of an Octopus and that of a human called? Give another example from the animal group and one from the plants of such organs. Name and explain the evolutionary process they exhibit.