Human Reproduction — BIOLOGY STD 12 Science — Question

(i) Write the name of the disease occurring as a result of point mutation.
(ii) Explain the lac operon.
(iii) Draw a labelled diagram of the lac operon.

Where does spermatogenesis occur in human testes? Describe the process of spermatogenesis upto the formation of spermatozoa.

A flower of brinjal plant following the process of sexual reproduction produces 360 viable seeds.
Answer the following questions giving reasons:
How many microspore mother cells must have undergone reduction division prior to dehiscence of another in the above case?

Describe the functions of the following:
Seminiferous tubules.

Answer the following questions:
At which stage of life does gametogenesis begin in human male and female respectively?

What is apomixis and what is its importance?

Study the 3 representative figures of age pyramid relating to human population given below and answer the following question:

1. Mention the names given to the 3 kinds of age profiles (i), (ii), and (iii).
2. Which one of them is ideal for a population and why?
3. How do such age-profile studies help policy makers get concerned about our growing population and prepare for future planning? (say for example: for the year 2022.)

[Hint. The age profile you would name as stable was prepared on the data available on January 2007].

Draw a labelled sketch of L.S. of pistil showing the progamous type of fertilization.

Differentiate between:

1. Predator and parasite.
2. S-Shaped and J-Shaped growth curve.