List of top Biology Questions asked in CBSE CLASS XII

Studying Diseases:
Where does EcoRI cut the palindrome? Write the events followed thereafter to form a recombinant DNA.
Name ‘A’ and ‘B’ fragments.
Chemical Safety Testing:
Write the ‘palindrome’ recognized by EcoRI.
How are such drugs consumed?
Production of Biological Products:
Draw a well-labelled diagram of the sectional view of a male gametophyte/microspore of an angiosperm and write the functions of any two parts labelled. (Any four labels).
Name the group of drugs whose skeletal molecule is shown below:
Study the graph given below that represents the changes in the thickening of the uterine wall in women ‘X’ and women ‘Y’ over a period of one month:
What does the graph with respect to women ‘X’ and woman ‘Y’ indicate? Give a suitable reason.
Explain Brood parasitism with the help of a suitable example.
Name any two hotspots in India.
Differentiate between grazing food chain and detritus food chain.
Assertion (A): Plasmids are autonomously replicating circular extra-chromosomal DNA.
Reason (R): Plasmids are usually present in eukaryotic cells.
What is artificial insemination in ART? Under what conditions is the person medically advised to go for it?
Assertion (A): A given fig species can be pollinated only by its partner wasp.
Reason (R): The wasp pollinates the fig inflorescence while searching for suitable egg-laying sites.
Why does a patient of ADA-deficiency require repeated infusions of genetically engineered lymphocytes? Suggest a possible permanent remedy.
Assertion (A): Patents are granted by governments to an inventor.
Reason (R): Patents prevent others from commercial use of an invention.
Assertion (A): Some aquatic ecosystems have inverted biomass pyramids.
Reason (R): More energy is required by organisms occupying higher trophic levels.
The ‘molecular scissors’ fall in the category of:
Homologous organs indicate:
Identify the category of genetic disorder depicted in the pedigree chart given below:
Which of the chromosome in a human possesses the least number of genes?
ELISA technique is based on the principle of:
In a fertilized ovule of an angiosperm, the cells in which n, 2n, and 3n conditions respectively occur are: