List of top Questions asked in PSEB XII

Briefly describe the Meselson and Stahl's experiment to prove that DNA replication is semi-conservative.
Define infertility. Explain any one assisted reproductive technology to check the problem of infertility.
What is Amniocentesis? For what purpose, it is used?
State and explain Mendel's law of dominance with the help of an example.
A woman carrier for haemophilia marries a normal man. Predict the possible genotypes and phenotypes of the offspring using a Punnett square. Also state percentages.
What happens to the corpus luteum in human females if the ovum is (a) fertilised (b) not fertilised?
Distinguish between innate and acquired immunity.
Define codominance. Explain the concept of co-dominance by taking an example of AB blood group in humans.
Menstrual cycle ceases during pregnancy.
Sex determination in honey bees is XX-XY type.
Floral parts are un-wettable in case of hydrophilous flowers.
Organic farming does not include chemical fertilizers.
A child may have O blood group if his father and mother have A and AB blood group respectively.
The lymphoid organs are the part of which system of human body?
What are primary lymphoid organs?
Name one primary lymphoid organ and one secondary lymphoid organ found in the human body.
The sterilisation procedure in males is called ________.
Coconut water is an example of a ________ endosperm.
ELISA stands for ________.
During spermiogenesis, nebenkern of the sperm develops from ________ of the spermatid.
Cyclosporin A, which is used as an immunosuppressive agent in organ-transplant patients, is produced by the fungus named ________.
The initiator codon, AUG codes for which of the following amino acids?
Which of the following organic acids can be produced on commercial scale by Aspergillus niger?
Heart shaped embryo is the feature of:
The cavity present in the blastula is called: