Class 12 > PYQ BIOLOGY > 2016 > Set 1

2016

History 3 Views

Q21
(a) Why must a cell be made 'competent’ in biotechnology experiments ? How does calcium ion help in doing so ? (b) State the role of ‘biolistic gun’ in biotechnology experiments
Free Response Question Hard View solution

Q22
Explain enzyme-replacement therapy to treat adenosine deaminase deficiency. Mention two disadvantages of this procedure.
Free Response Question Hard View solution

Q23
Name and explain the type of interaction that exists in mycorrhizae and between cattle egret and cattle
Free Response Question Medium View solution

Q24
Differentiate between primary and secondary succession. Provide one example of each.
Free Response Question Medium View solution

Q25
Large number of married couples the world over are childless. It is shocking to know that in India the female partner is often blamed for the couple being childless. (a) Why in your opinion the female partner is often blamed for such situations in India ? Mention any two values that you as a biology student can promote to check this social evil. (b) State any two reasons responsible for the cause of infertility. (c) Suggest a technique that can help the couple to have a child where the problem is with the male partner.
Free Response Question View solution

Q26
a) Explain the menstrual phase in a human female. State the levels of ovarian and pituitary hormones during this phase. (b) Why is follicular phase in the menstrual cycle also referred as proliferative phase ? Explain. (c) Explain the events that occur in a graafian follicle at the time of ovulation and thereafter. (d) Draw a graafian follicle and label antrum and secondary oocyte.
Free Response Question View solution

Q27
(a) As a senior biology student you have been asked to demonstrate to the students of secondary level in your school, the procedure(s) that shall ensure cross-pollination in a hermaphrodite flower. List the different steps that you would suggest and provide reasons for each one of them. (b) Draw a diagram of a section of a megasporangium of an angiosperm and label funiculus, micropyle, embrvosac and nucellus.
Free Response Question View solution

Q28
Describe Meselson and Stahl's experiment that was carried in 1958 on E.Coli. Write the conclusion they arrived at after the experiment.
Free Response Question Hard View solution

Q29
a) Describe the process of transcription in bacteria. (b) Explain the processing the hnRNA needs to undergo before becoming functional mRNA in eukaryotes.
Free Response Question Hard View solution

Q30
26. (a) Name the two growth models that represent population growth and draw the respective growth curves they represent.
(b) State the basis for the difference in the shape of these curves. (c) Which one of the curves represent the human population growth at present? Do you think such a curve is sustainable? Give reason in support of your answer.
Free Response Question Hard View solution
2
3
4