Sunday, May 11, 2014

Summer Vacation BIOLOGY HOMEWORK CLASS XII

KENDRIYA VIDYALAYA  ALIGANJ LUCKNOW
 SUMMER VACATION HOME WORK  CLASS XII C BIOLOGY 2014-2015
1.      Why is reproduction essential for organisms?
2.      Which is a better mode of reproduction sexual or asexual? Why?
3.      Why is the offspring formed by asexual reproduction referred to as clone?
4.      Offspring formed due to sexual reproduction have better chances of survival. Why? Is this statement always true?
5.      How does the progeny formed from asexual reproduction differ from those formed by sexual reproduction?
6.      Distinguish between asexual and sexual reproduction. Why is vegetative reproduction also considered as a type of asexual reproduction?
7.      Differentiate between gametogenesis from embryogenesis.
8.      Describe the post-fertilisation changes in a flower.
9.      What is a bisexual flower? Collect five bisexual flowers from your neighbourhood find out their common and scientific names.
10.  Examine a few flowers of any cucurbit plant and try to identify the staminate and pistillate flowers. Do you know any other plant that bears unisexual flowers?
11.  Why are offspring of oviparous animals at a greater risk as compared to offspring of viviparous animals?
12.  What are chasmogamous flowers? Can cross-pollination occur in cleistogamous flowers? Give reasons for your answer.
13.  Mention two strategies evolved to prevent self-pollination in flowers.
14.  What is self-incompatibility? Why does self-pollination not lead to seed formation in self-incompatible species?
15.  What is bagging technique? How is it useful in a plant breeding programme?
16.  What is triple fusion? Where and how does it take place? Name the nuclei involved in triple fusion.
17.  Why do you think the zygote is dormant for sometime in a fertilized ovule?
18.  Make a neat and clean labelled diagram of typical ovule and monocot seed
19.  Why is apple called a false fruit? Which part(s) of the flower forms the fruit?
20.  What is meant by emasculation? When and why does a plant breeder employ this technique?
21.  If one can induce parthenocarpy through the application of growth substances, which fruits would you select to induce parthenocarpy and why?
22.  Explain the role of tapetum in the formation pollen-grain wall.
23.  What is apomixis and what is its importance?
24.  What is lactational amenorrhoea
25.  Explain the functioning of oral contraceptive pills
26.  Write short notes on (a) ART (b) MTP
27.  List common STDs and their causative agents .How can these be prevented  ?
28.  Is sex education is  necesarry in school ? Why ?
29.  Expand following  IVF,ZIFT,IUT,GIFT,ICSI,AIT

30.  Write short notes on (a) Amniocentesis (b)Chorionic Villi Sampling