Question

(c) Osmosis
(e) Active transport
(f) Tonicity
(g) Root pressure
Give reasons for the following:
(a) If you sprinkle some common salt on grass growing
on a lawn, it is killed at that spot.
(b) If you uproot a plant from the soil, its leaves soon wilt.
(c) It is better to transplant seedlings in a flower-bed in
the evening and not in the morning.
(d) A plant cell when kept in a hypertonic salt solution for
about 30 minutes turns flaccid.
(e) Potato cubes when placed in water become firm and
increase in size.
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Answer 1

Explanation:

. MULTIPLE CHOICE TYPE

(Select the most appropriate option in each case)

1. Absorption of water by the plant cells by surface attraction is called:

(a) Diffusion (b) Osmosis

(c) Imbibition (d) Endosmosis

Solution:-

c) Imbibition

2. A plant cell placed in a certain solution got plasmolysed. What was the kind of solution?

(a) Isotonic sugar solution (b) Hypotonic salt solution

(c) Hypertonic salt solution (d) Isotonic salt solution

Solution:-

(c) Hypertonic salt solution

3. The state of a cell in which the cell wall is rigid and stretched by the increase in volume due to the absorption of water is called

(a) Flaccidity (b) Turgidity

(c) Capillarity (d) Tonicity

Solution:-

(b) Turgidity

4. Which one of the following is a characteristic NOT related with the suitability of the roots for absorbing water?

a) Tremendous surface area

b) Contain cell sap at higher concentration than the surrounding water

c) Root hairs have thin cell walls

d) Grow downward into the soil

Solution:-

d) Grow downward into the soil

5. Movement of molecules of a substance from the region of their higher concentration to the region of their lower concentration without the involvement of a separating membrane, is called:

a) Osmosis b) Diffusion

c) Active transport d) Capillarity

Solution:-

b) Diffusion

6. Osmosis and diffusion are the same except that in osmosis there is

a) a freely permeable membrane