List of top Questions asked in PSEB XII

During the processing of proinsulin into mature insulin :
In a 28-days human ovarian cycle, when does ovulation typically take place?
If an organism’s body pattern resembles its environment, making it difficult to spot, it is called :
Name the mode of pollination by insects. Give any five characteristics of the flowers pollinated by insects.
During the life cycle of Plasmodium, sexual reproduction takes place in :
Vitamin whose content increases following the conversion of milk into curd by lactic acid bacteria is :
Differentiate between homozygous and heterozygous individuals.
What is linkage? Discuss any two factors affecting linkage.
What is meant by monosporic development of female gametophyte?
Name the causative agent of Amoebiasis. Mention its symptoms and mode of transmission. State any two precautionary measures.
Name the parasite which causes Malaria. At what stage does it enter the human body? Mention symptoms and two control measures.
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.
What are Intra-uterine devices (IUDs)? Discuss their mode of action.
What are the measures one has to take to prevent from contracting STDs?
In what way, anaerobic sludge digestion is important in sewage treatments?
List any four harmful effects caused by alcohol or drug abuse.
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.
If the sequence of the template strand in a transcription unit is written as follws :
5' - ATGCATGCATGCATGC - 3'
what is the sequence of mRNA?
What is Human Genome Project? Why is the Human Genome Project called a Mega project?
Give the characteristics of genetic code.
Briefly describe the Meselson and Stahl's experiment to prove that DNA replication is semi-conservative.
State and explain Mendel's law of dominance with the help of an example.
Define codominance. Explain the concept of co-dominance by taking an example of AB blood group in humans.