List of top Biology Questions asked in PSEB XII

The pyramid of ________ is always upright and can never be inverted.
A woman with blood group ‘AB’ marries a man with blood group “O”. Which of the following statements is true about the possibilities of inheritance of the blood groups?
A farmer noticed that his apple trees were not bearing as much fruits as expected, despite having plenty of flowers. He observed that the bee population in his orchard had decreased significantly this season due to recent pesticide usage. Which type of pollination is likely being affected in this case, and what could be a possible solution?
During the processing of proinsulin into mature insulin :
The Red Data Book deals with :
If an organism’s body pattern resembles its environment, making it difficult to spot, it is called :
In a 28-days human ovarian cycle, when does ovulation typically take place?
The letter R in EcoRI is derived from the :
Vitamin whose content increases following the conversion of milk into curd by lactic acid bacteria is :
During the life cycle of Plasmodium, sexual reproduction takes place in :
Name the mode of pollination by insects. Give any five characteristics of the flowers pollinated by insects.
What are the measures one has to take to prevent from contracting STDs?
What are Intra-uterine devices (IUDs)? Discuss their mode of action.
What is fertilization? In which part of the human female reproductive system does it occur? Explain, with the help of diagrams, various physical and chemical events of fertilization in humans.
Name the causative agent of Amoebiasis. Mention its symptoms and mode of transmission. State any two precautionary measures.
Differentiate between homozygous and heterozygous individuals.
Name the parasite which causes Malaria. At what stage does it enter the human body? Mention symptoms and two control measures.
What is linkage? Discuss any two factors affecting linkage.
What is meant by monosporic development of female gametophyte?
In what way, anaerobic sludge digestion is important in sewage treatments?
How has the bacterium Bacillus thuringiensis helped us in controlling caterpillars of insect pests?
Briefly describe the role of microbes in household food processing.
(a) Define transcription.
Briefly describe the Meselson and Stahl's experiment to prove that DNA replication is semi-conservative.
List any four harmful effects caused by alcohol or drug abuse.