Human Reproduction — BIOLOGY STD 12 Science — Question

1. Mention the exact location or the site in a flowering plant, where the following developments take place:

1. Deposition of sporopollenin.
2. Triple fusion.
3. Release of male gametes.
4. Megasporogenesis.

2. Draw a labelled diagram of a male gametophyte of an angiosperm.

List three symptoms of high altitude sickness and state three adaptations to overcome it.

Name the stage ofthe Plasmodium thall is trrnsmitted to human body by the vector. Describe the life cycle of the plrasite in humans.
OR
Trace the life cycle of Plasmodium in humans from the stage of entry, until it is picked up by the female Anopheles.

What is adaptive radiation? When can adaptive radiation be referred to as convergent evolution? Give an example.

Name the genus to which baculoviruses belong. Describe their role in the integrated pest management programmes.

Name the part of the genital tract of human female which acts as ‘womb’.

"Prevention is better than cure' is an apt slogan to safeguard adolescents from drug abuse. List any six steps that could be taken in this regard.

1. Draw schematic diagrams of segments of a vector and a foreign DNA with the sequence of nucleotides recognised by EcoRI.
2. Draw the vector DNA segment and foreign DNA segment after the action of EcoRI and label the sticky ends produced.

A patient complains of suffering from constipation, stomach ache, stool with blood clots and excess mucous.
The physician diagnosed it as amoebiasis, after stool test.
a. Write the scientific name of the microbe identified in the stool sample.
b. How do you think, the patient must have contracted it?
c. Write your suggestions to the patient to avoid infection in future.

Draw the diagram of a mature embryo sac and show its 8-nucleate, 7-celled nature. Show the following parts: antipodals, synergids, egg, central cell, polar nuclei.