Model Paper 3 — BIOLOGY STD 12 Science — Question

Explain the internal structure of testis (Figure is not essential).

What are the consequences of population explosion?

Study the given pedigree chart and answer the questions that follow:

Is the trait recessive or dominant?

Explain with the help of an example each, male and female heterogamety mechanisms of sex determination.

1. Construct a complete transcription unit with promoter and terminator on the basis of the hypothetical coding strand given below.

2. Write the RNA strand transcribed from the above transcription unit along with its polarity.

Differentiate between vaccination and immunisation. Describe the two types of vaccines with suitable examples?

List any four major categories into which contraception methods could be broadly classified. Explain briefly each category giving one example of each.

Identify a, b, c, d, e and f in the table given below:

	Organism	Bioactive molecule	Use
1. 2. 3.	Monascus perpureus (yeast) c e	a d Cyclosporin A	b antibiotic f

A large number of married couples the world over are childless. It is shocking to know that in India the female partner is often blamed for the couple being childless.

1. Why in your opinion the female partner is often blamed for such situations in India? Mention any two values that you as a biology student can promote to check this social evil.
2. State any two reasons responsible for the cause of infertility.
3. Suggest a technique that can help the couple to have a child where the problem is with the male partner.