The plant hormone whose concentration stimulates the cells to grow longer on the side of the shoot which is away from light is:
[1 marks]
Plants have neither a nervous system nor muscles, even then they respond to stimuli. For example, the leaves of chhui-mui (touch-me-not) plant when touched begin to fold up and droop.
(a) How is the information communicated in "touch-me-not" plants?
(b) What enables the plant cells to bring out the observable response ?
(c) Differentiate the movement mentioned above from the movement of tendrils in a pea plant.
[3 marks]
In a nerve cell, the site where the electrical impulse is converted into a chemical signal is known as:
[1 marks]
| (A) |
How is the movement of leaves of a sensitive plant different from the downward movement of the roots? |
| OR | |
| (B) | There is a hormone which regulates carbohydrate, protein and fat metabolism in our body. Name the hormone and the gland which secretes it. Why is it important for us to have iodised salt in our diet? |
[2 marks]
Define reflex action. With the help of a flow chart show the path of a reflex action such as sneezing.
[3 marks]
Select from the following the correct statement about tropic movement in plants:
[1 mark]
(a) Write the role of insulin in regulating blood sugar levels in human body. Mention the disease caused due to it.
(b) How is the timing and the amount of release of insulin in the blood regulated?
[2 marks]