SECTION-A (Very Short Answer Type Questions ) (in 10-20 words)
1. Give a example of a plant hormone that promotes growth.
2. Give one important uses of washing soda and baking soda.
3. Give the chemical name and chemical formula of Washing soda.
4. Why is the use of lodised salt advisable?
5. of a plant thName the part at exhibits positive phototropism
6. Give an example of a phenomenon where Tyndall effect can be observed.
7. How does Phototropism occur in plants?
8. Name the asexual reproduction method in Spirogyra.
9. Chemical formula for bleaching powder is
10. Which part of the brain which controls the involuntary actions like blood pressure,
SECTION-B
Answers
Answer:
1.Auxins promote stem elongation, inhibit growth of lateral buds (maintains apical dominance). They are produced in the stem, buds, and root tips. Example: Indole Acetic Acid (IA). Auxin is a plant hormone produced in the stem tip that promotes cell elongation.
2.Sodium carbonate (washing soda) is used in glass, soap and paper industries.
It is used for removing permanent hardness of water.
It is used in the manufacture of borax, ii) Uses of baking Soda : ...
It is also used in soda - acid fire extinguishers. 3)It acts as mild antiseptic.
3.Washing soda is a whitish, odourless powder. Its chemical formula is Na2CO3 and is better known as sodium carbonate.
4.Iodine is needed by the thyroid gland for the production thyroxin hormone. ... If quantity of iodine in food is lesser than required, then the neck will swell up due to the enlargement of thyroid gland. This deficiency disease is known as goitre. Therefore the iodized salt is advised.
5.The movement of plant parts towards the light source is known as positive phototropism, whereas the movement of plant parts away from light is known as negative phototropism. The stems of plants show positive phototropism as they grow upwards.
6.When a beam of light is directed at a glass of milk, the light is scattered. This is a great example of the Tyndall effect. When a torch is switched on in a foggy environment, the path of the light becomes visible.
7.Phototropism is the growth of an organism in response to a light stimulus. ... The cells on the plant that are farthest from the light have a chemical called auxin that reacts when phototropism occurs. This causes the plant to have elongated cells on the furthest side from the light.
8.Spirogyra species can reproduce both sexually and asexually. Asexual, or vegetative, reproduction occurs by simple fragmentation of the filaments. Sexual reproduction occurs by a process known as conjugation, in which cells of two filaments lying side by side are joined by outgrowths called conjugation tubes.
9.Ca(ClO)2
10.The medulla oblongata is part of the brain stem that controls most of these involuntary actions (The brain stem is the posterior part of the brain that is continuous with the spinal cord).