Molecular Basis of Inheritance — BIOLOGY STD 12 Science — Question

Who proposed chromosomal theory of inheritance? Point out any two similarities in the behaviour of chromosomes and genes.

What are transgenic bacteria? Illustrate using any one example.

State the role of T lymphocytes and B lymphocytes in developing acquired immunity against certain diseases.

OR

Name the different types of cells that are responsible for producing the acquired immune response in a human body. How do these cells respond when a pathogen enters the body?

OR

 Name the two special types of lymphocytes in humans. How do they differ in their roles in immune response?

How does tobacco smoking lead to oxygen deficiency in human body?

Shyam Lal and his wife have been advised by the gynaecologist to go for artificial insemination. What may have been the reason for the doctor to give such an advice? Explain.

Given below are the stages in human reproduction. Write them in correct sequential order.
Insemination, Gametogenesis, Fertilisation, Parturition, Gestation, Implantation

Identify the given diagram. What it is used for?

Why do prokaryotes (bacteria) have restriction enzymes but not eukaryotes?

What is the cause of Phenylketonuria? Explain the disorder.

An mRNA strand has a series of codon out of which three are given below:

1. AUG
2. UUU
3. UAG

1. What will their DNA codon be translated into?
2. What are the DNA codon that would have transcribed these RNA codon?