The pattern in which the question papers are being set for a particular subject is quite different from the manner in which the course structure is defined actually. Though the course curriculum is predefined, there are certainly some gaps between the question paper formed and the content of the course. Henceforth, students need to identify these gaps and catch up where the textbooks left off, if they want to get acquainted with the examination pattern. And, they can do it easily by checking out previous year question papers and their solutions. This not only helps them prepare for exams in a better manner but also leads them to the depth which the topic should be studied with.
Some solved questions from CBSE Class 12th Biology Question Paper 2011-Set III, are given here
Q. List the changes the primary oocyte undergoes in the tertiary follicular stage in the human ovary.
Ans. Oogenesis leads to the formation of oogonium or egg. Cell division start and enters to prophase I ofmitotic division and gets arrested, called as primary oocyte. Primary oocyte are surrounded by granulosa cells called as primary follicle, these primary follicles gets surrounded by granulosa cells and theca so called secondary follicles.
Q. Why are cattle and goats not seen browsing on Calotropis growing in the fields?
Ans. Browsing of cattle and goat on Calotropisis an unusual phenomenon as the grass is highly toxic and produces chemicals like cardiac glycosides, nicotine, caffeine, quinine, strychnine, opium, etc.which provides them protection against grazers.
Q. Mention the type of allele that expresses itself only in homozygous state in an organism.
Ans. Homozygous organism with sickle cell anemia display similar allele i.e.HbS (HbSHbS)
Q. Malaria, typhoid, pneumonia and amoebiasis are some of the human infectious diseases. Which ones of these are transmitted through mechanical carriers ?
Ans. Amoebiasis is caused by protozoan parasite, transmitted by Houseflies, mechanical carriers.
Q. Name the phenomenon and the cell responsible for the development ofa new individual without fertilization as seen in honey bees.