Molecular Basis of Inheritance — BIOLOGY STD 12 Science — Question

In the diagram given below, show the path of a pollen tube from the pollen on the stigma into the embryo sac. Name the components of egg apparatus.

Explain how biodiversity is important for human.

Microbes have various contributions to the human welfare. For example, lactic acid bacteria help in checking disease causing microbes in our stomach. With reference to this fact, state the contribution of different microbes in the process of digestion in ruminants.

Draw well labelled diagram of semeniferous tubules.

Draw a well labelled diagram of mature graafian follicle.

How many eggs are released by a human ovary in a month? How many eggs do you think would have been released if the mother gave birth to identical twins? Would your answer change if the twins born were fraternal?

The method developed by Eli Lilly using R-DNA technology has received great support from diabetic patients. Explain, how?

Write any four facts proved by the study of fossils regarding the development of life?

Rajesh was doing gel electrophoresis to purify DNA fragments. Given below is the sketch of the observations of the experiment performed by him.

1. At which end he would have loaded the samples and where?
2. Analyse the reason for different positions taken up by the DNA bands.
3. Elaborate the step he would have followed to visualise DNA bands.

A team of students are preparing to participate in the interschool sports meet. During a practice session, you find some vials with labels of certain cannabinoids.

1. Will you report to the authorities? Why?
2. Name a plant from which such chemicals are obtained.
3. Write the effect of these chemicals on human body.