List of top Biology Questions asked in CBSE CLASS XII

Suggest the aspects of reproductive health which need to be given special attention in the present scenario.
Can you think and answer how a reporter enzyme can be used to monitor transformation of host cells by foreign DNA in addition to a selectable marker?
Can you recall meiosis and indicate at what stage a recombinant DNA is made?
Name the functions of the following.
  1. Corpus luteum
  2. Endometrium
  3. Acrosome
  4. Sperm tail
  5. Fimbriae
Differentiate between:
  1. Hypocotyl and epicotyl;
  2. Coleoptile and coleorrhiza;
  3. Integument and testa;
  4. Perisperm and pericarp
Fill in the blanks:
  1. Human Reproduction _____________ .(asexually/sexually)
  2. Humans are _________. (oviparous/viviparous/ovoviviparous)
  3. Fertilization is __________in humans. (external/internal)
  4. Male and female gametes are __________. (diploid/haploid)
  5. Zygote is ___________. (diploid/haploid)
  6. The process of release of the ovum from a mature follicle is called _____________.
  7. Ovulation is induced by a hormone called the __________.
  8. The fusion of the male and the female gametes is called ____________.
  9. Fertilization takes place in the __________.
  10. The zygote divides to form __________, which is implanted in uterus.
  11. The structure which provides vascular connection between the fetus and uterus is called __________.
What is triple fusion? Where and how it take place? Name the nuclei involved in triple fusion.
What is bagging technique? How is it useful in a plant breeding programme?
What are chasmogamous flower? Can cross-pollination occur in cleistogamous flowers? Give reason for your answer.
What is meant by monosporic development of female gametophyte?
Arrange the following terms in the correct developmental sequence: Pollen grain, sporogenous tissue, microspore tetrad, pollen mother cell, male gametes
What is self-incompatibility? Why does self-pollination not lead to seed formation in self-incompatible species?
Differentiate between microsporogenesis and megasporogenesis. Which type of cell division occurs during these events? Name the structures formed at the end of these two events.
Name the parts of an angiosperm flower in which development of male and female gametophyte take place.
Why is apple called a false fruit? Which part(s) of the flower forms the fruit?

If the sequence of one strand of DNA is written as follows: 

5'-ATGCATGCATGCATGCATGCATGCATGC-3' 

Write down the sequence of complementary strand in 5'→3' direction

Group the following as nitrogenous bases and nucleosides: Adenine, Cytidine, Thymine, Guanosine, Uracil and Cytosine.
What is pedigree analysis? Suggest how such an analysis can be useful.

Correct the following statements.
(a) Surgical methods of contraception prevent gamete formation.
(b) All sexually transmitted diseases are completely curable.
(c) Oral pills are very popular contraceptives among rural women.
(d) In E.T.techniques embryos are always transferred into the uterus.

State True/False with explanation
(a) Abortions could happen spontaneously too. (True/False)
(b) Infertility is defined as the inability to produce a viable offspring and is always due to abnormalities/defects in the female partner. (True/False)
(c) Complete lactation could help as a natural method of contraception. (True/False)

(d) Creating awareness about sex related aspects is an effective method to improve reproductive health of the people. (True/False)

What are the measures one has to take to prevent from contracting STDs ?
Suggest some methods to assist infertile couples to have children.

Amniocentesis for sex determination is our country. Is this ban necessary? Comment

Removal of gondas cannot be considered as a contraceptive option. Why?
Is the use of contraceptives justified? Give reasons.