Short Answer Type(a) Name any two places where it is essential to install electrostatic percipitators. Why is it required to do so?
(b) Mention one limitation of the electrostatic precipitator.
Prior to a sports event blood and urine samples of sports-persons are collected for drug tests.
(a) Why is there a need to conduct such tests/
(b) Name the drugs the authorities usually look for.
(c) Write the generic names of two plants from which these drugs are obtained.
Given below is a list of six micro-organism. State their usefulness to humans.
(a) Nucleopolyhedrovirus
(b) Saccharomyces cervisiae
(c) Monascus purpureus
(d) Trichoderma polysporum
(e) Peniciliu notatum.
(f) Propionibacterium sharmanni
Reproductive and Child Healthcare (RCH) programmes are currently in operation. One of the major tasks of these programmes is to create awareness amongst people about the wide range of reproduction related aspects. As this is important and essential for building a reproductively healthy society.
(a) Providing sex education in schools in one of the ways to meet this goal. Give four points in support of your opinion regarding this statement.
(b) List any two 'indicators' that indicate a reproductively healthy society.
Describe the experiment that helped demonstrate the semi-conservative mode of DNA replication
Long Answer Type(a) Explain the post-pollination events leading to seed production in angiosperms.
(b) List the different types of pollination depending upon the source of pollen grains.
(a) Briefly explain the events of fertilisation and implantation in an adult human female.
(b) Comment on the role of placenta as an endocrine gland.
(a) How are the following formed and involved in DNA packaging in a nucleus of a cell?
(b) Differentiate between Euchromatin and Heterochromatin
i. Histone octomer - The histones are positively charged, basic proteins called histones. Histones are rich in basic amino acids like lysines and arginines. Histones are organised to form a unit of eight molecules called an histone octamer.
ii. Nucleosome - The negatively charged DNA is wrapped around the positively charged histone octamer to form the structure called nucleosome. A typical nucleosome contains 200 bp of DNa helix.
iii. Chromatin - The nucleosome are the repeating units and together form chromatin. The nucleosome appear like beads on strings on the chromatin.
The chromatin is packaged to form chromatin fibres that further coil and condense at metaphasic stage of cell division to form chromosome. This involves non-histone proteins for packaging called the No-histone Chromosomal (NHC) proteins.
(b)
| Euchromatin | Heterochromatin |
| Region of the chromatin which is loosely packed. | Region of the chromatin which is densely packed |
| Stains light | Stains dark. |
(a) Why should we conserve biodiversity? How can we do it?
(b) Explain the importance of biodiversity hot-spots and sacred groves.
(a) Represent diagrammatically three kinds of age-pyramids for the human population.
(b) How does an age pyramid for human population at given point of time helps the policy makers in planning for the future.
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