Introduction to Transpiration.

Q.

Why do desert plants keep stomata open during day time and close at night?

Q.

What are guard cells?

Q.

The diagram given represents a structure found in a leaf.

Study the same and answer the questions that follow.

1. Name the parts labeled A and B.
2. What is the biological term for the above structure?
3. What is the function of the part labeled A?
4. Mention two structural features of A, which help in the function mentioned in (3) above.
5. Where is this structure likely to be found in a leaf?
6. The above structure helps in the process of transpiration. Explain the term transpiration.
7. How many other cells are found surrounding this structure as seen in the diagram?

Q.

All plants give out oxygen during the day and carbon dioxide during night do you agree with the statement give reasons. And also tell if leaves of a healthy potted plant were coated with Vaseline all the plant remain healthy for a long time give reasons

Q. Given below are the diagrams of a certain structure in plants in two conditions. [5 MARKS]

(a) Name the structure shown in the diagram.
(b) Name the parts numbered 1 to 5.
(c) What is the most apparent difference between A and B in the structure shown?
(d) Describe the mechanism which brings about the change in the structure depicted in A and B.

Q.

What is the characteristic feature of the cobalt chloride paper used in the transpiration experiment?

1. Paper turns pink in the presence of water.

2. Paper turns blue in the presence of water.

3. Paper turns blue in the presence of oxygen.

4. Paper turns pink in the presence of carbon dioxide.

Q. Do guard cells have rigid or elastic walls? Justify your answer

Q.

Where are stomata generally found?

1. Root

2. Flower

3. Leaf

4. Stem

Q.

The loss of water from the surface of plants is called ___ .

1. Transpiration

2. Food uptake

3. Water uptake

4. All of the above

Q.

Name the process by which plants get rid of excess water.

Q.

Why would a plant want to lose water through transpiration?

Q.

Herbaceous plants growing in well-watered soils are found to wilt on a hot day. Why?

Q.

The stomatal pore opens when:

1. Guard cells swell up

2. Chloroplast of guard cells shrink

3. Guard cells shrink

4. Chloroplast of guard cells swell up

Q.

Most water absorbed by the plant is lost during transpiration.

1. True

2. False

Q.

Give reason for the following:

Balsam plant wilt during mid-day even if the soil is well watered.

Q. Stomata of desert plants remain closed during day time. How do they take up $C{O}_2$ and perform photosynthesis ?

Q.

________ have guard cells.

Q. The rate of transpiration is ___________ to the humidity in air.

1. inversely proportional
2. directly proportional
3. independant
4. equal

Q. Which among the following statements are correct regarding the guard cells?

1. They are tiny openings that allow the intake of $CO2$.
2. They provide mechainical support to the plant.
3. They introduce morphology in leaf that affect gas exchange.
4. They regulate the closing and opening of stomata.

Q.

Assertion (A): Transpiration is a biological activity

Reason (R): Transpiration occurs through living tissues of aerial parts of plants

1. Both A & R are true and R explains A

2. Both A & R are true and R does not explain A

3. A is true and R is false

4. Both A & R are false

Q. A student puts a drop of reaction mixture of a saponification reaction first on a blue litmus paper and then on a red litmus paper. He may observe that :

(a) There is no change in the blue litmus paper and the red litmus paper turns white.

(b) There is no change in the red litmus paper and the blue litmus paper turns red.

(c) There is no change in the blue litmus paper and the red litmus paper turns blue.

(d) No change in colour is observed in both the litmus papers.

Q. Which among the following objectives regarding transpiration are achieved by Ganong's potometre?

1. It measures the rate of water intake by a plant.
2. Demonstrates the suction force created by transpiration.
3. Demonstrates unequal transpiration from the two surfaces of a dorsiventral leaf.
4. Demonstrates unequal transpiration from the two surfaces of an isobilateral leaf.

Q.

Definition of Transpiration:

1. The process by which green plants and certain other organisms transform light energy into chemical energy.

2. The evaporative loss of water from the aerial parts of the plant.

3. The process of oxidizing food molecules, like glucose, to carbon dioxide and water.

4. The movement of air or dissolved gases into and out of the stomata.

Q.

The diagram of an apparatus given below demonstrates a particular process in plants. Study the same and answer the questions that follow

1. Name the apparatus.
2. Which phenomenon is demonstrated by this apparatus?
3. Explain the phenomenon mentioned in 2. above.
4. State two limitations of using this apparatus.
5. What is the importance of the air bubble in this experiment?
6. Name the structure in a plant through which the above processes take place.

Q.

During transpiration, water leaves the cells of the plant in the form of ___ .

1. Water vapour

2. Ice

3. Sugar

4. None of the above

Q.

The leaves of certain plants exhibit droplets of water along their margin in the morning. This is known as________.

1. guttation

2. transpiration

3. imbibition

4. absorption

Q.

Tissue in the leaf that has the highest concentration of chloroplasts.

1. Palisade mesophyll

2. Spongy mesophyll

3. Epidermis

4. Guard cells

Q. Choose the correct statements out of the following.

1. There is unequal transpiration from the two surfaces of a dorsiventral leaf.
2. There is equal transpiration from the two surfaces of a dorsiventral leaf.
3. Desert plants have thicker cuticles to cut down photosynthesis.
4. Desert plants have thicker cuticles to cut down transpiration.

Q.

Water evaporates through tiny openings present in the leaves known as ___

Q. Stomata of desert plants remains closed during the day. Explain how and when they take up carbon dioxide to perform photosynthesis?