Role of Stomata in Minimizing Photorespiration

Q. Leaves that appear wilted during the daytime recovers at night because

1. stomata closes during night, temperature decreases, transpiration is reduced and plant is able to absorb more water from the soil
2. transportation of organic substances increase during night
3. All of the above
4. light is essential for photosynthesis

Q.

Assertion : The opening of stoma is also aided due to the orientation of the microfibrils in the cell walls of the guard cells.

Reason : Cellulose microfibrils are oriented radially rather than longitudinally, making it easier for stoma to open.

1. if A is true but R is false

2. if both A and R are false.

3. if both A and R are true but R is not the correct explanation of A

4. if both A and R are true and R is the correct explanation of A

Q. Which is not true regarding stomata?

1. They are turgor operated valves
2. Have differentially thickened walls of guard cells
3. They close when guard cells are turgid
4. Show scotoactive opening in CAM plants

Q. Opening of stomata is not affected by

1. K⁺ ions
2. Starch
3. N₂
4. None of these

Q.

What is importance of turgidity in plants?

Q. Leaves which appear wilted in the day time recover at night because :

1. Respiration and translocation of organic substance both increases
2. Light is essential for photo synthesis
3. The plant is sleeping because of dark conditions
4. The stomata close down, temperature decrease, transpiration is reduced and the plant is able to absorb more water from the soil

Q. Excessive transpiration results in the wilting of the leaves. Give suitable explanation.

Q.

C4 plants, by decreasing photorespiration and efficiently carrying out photosynthesis, can?

1. Decrease stomatal openings and thereby reduce water loss.

2. Decrease stomatal openings and thereby reduce leaf temperature.

3. Increase stomatal openings and thereby increase water loss.

4. Increase stomatal openings and thereby increase leaf temperature.

Q. Leaves which appear wilted in the day time and recover at night because

1. Light is essential for photosynthesis.
2. The stomata closes, temperature decreases, transpiration is reduced and the plant is able to absorb more water from the soil.
3. Respiration and translocation of organic substance, both increases.
4. The plant is inactive because of dark conditions.

Q. Stomata opens during the day and closes during the night because

1. Enzymes convert starch into sugar during the night
2. Photosynthesis takes place during daytime only
3. Formation of sugar increases osmotic concentration of cell sap which results in absorption of water which provide turgidity to guard cells
4. None of the above

Q. Rate of transpiration will increase if

1. Relative Humidity increases
2. Relative Humidity decreases
3. Relative Humidity remains unchanged
4. Water potantial gradient remains unchanged

Q. What are the functions of the stomata?

(i)	Transpiration
(ii)	Guttation
(iii)	Take in oxygen
(iv)	Give out oxygen

1. (iii) and (iv)
2. Only (i)
   
3. (ii), (iii) and (iv)
4. (i) and (iv)

Q. Underground stems of Colocasia and ginger are modified to perform

1. photosynthesis
2. storage and perennation
3. respiration and absorption of water
4. conduction of water and minerals

Q. Stomata opens during the day and closes during the night because

1. Enzymes convert starch into sugar during the night
2. Photosynthesis takes place during daytime only
3. Formation of sugar increases osmotic concentration of cell sap which results in absorption of water which provide turgidity to guard cells
4. None of the above

Q. Leaves which appear wilted in the day time recover at night because :

1. The stomata close down, temperature decrease, transpiration is reduced and the plant is able to absorb more water from the soil
2. Respiration and translocation of organic substance both increases
3. Light is essential for photo synthesis
4. The plant is sleeping because of dark conditions

Q. When strips of chloride papers are placed on either side of a dorsiventral leaf, why the strip on the lower side become speedily pink?

1. More $C{O}_2$ is evolved from the lower side.
2. More $O_2$ is evolved from the lower side.
3. All of the above.
4. More $H_{2}O$ is lost from the lower side.

Q. Stomata opening and closing is due to the permeability of the guard cell. This fact was revealed by

1. Von Mohl
2. Linsbauer
3. Lloyd
4. Mansfield

Q. Closed stomata reduces

1. Rate of transpiration
2. Amount of carbon dioxide entering the leaf
3. Both rate of transpiration and amount of carbon dioxide entering the leaf
4. Rate of respiration

Q. List any three major factors that accelerate the rate of transpiration.

Q. Enzyme connected with opening and closing of stomata is

1. $\alpha -$ amylase
2. Pyruvic kinase
3. PEP carboxylase
4. RuDP carboxylase

Q. Which one gives the most valid and recent explanation for stomatal movements?

1. Transpiration
2. Guard cell photosynthesis
3. Potassium influx and efflux
4. Starch hydrolysis

Q. What is the name of those cells in the leaf of a plant which control the opening and closing of stomata?

Q. Leaves that appear wilted during the daytime recovers at night because

1. light is essential for photosynthesis
2. stomata closes during night, temperature decreases, transpiration is reduced and plant is able to absorb more water from the soil
3. transportation of organic substances increase during night
4. All of the above

Q.

C4 plants, by decreasing photorespiration and efficiently carrying out photosynthesis, can?

1. Decrease stomatal openings and thereby reduce water loss.

2. Decrease stomatal openings and thereby reduce leaf temperature.

3. Increase stomatal openings and thereby increase water loss.

4. Increase stomatal openings and thereby increase leaf temperature.

Q. When an oak leaf stoma is open more widely, the most likely process involved is

1. The atmosphere outside the stoma is becoming less humid.
2. Water molecule are entering in the guard cells through adjacent cells.
3. Auxins are accumulating in the guard cells.
4. Salts molecule are being excreted by the adjacent guard cells.

Q. Assertion :The rate of transpiration is indirectly proportional to relative humidity. Reason: If the outer air is humid, it will reduce the diffusion of water vapour from intercellular spaces of leaf to the outer atmosphere.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
3. Assertion is correct but Reason is incorrect.
4. Assertion is incorrect but Reason are correct.

Q. Which pigment regulate opening and closing of stomata?

1. Chlorophyll
2. Carotenoid
3. Phytochrome
4. Flavin

Q. Stomata opens during the day and closes during the night because

1. Enzymes convert starch into sugar during the night
2. None of the above
3. Formation of sugar increases osmotic concentration of cell sap which results in absorption of water which provide turgidity to guard cells
4. Photosynthesis takes place during daytime only

Q. The figure given below is a part of leaf.
Which of the following is the function of part labelled X in the given figure ?

1. Take in water
2. Take in food
3. Take in carbon dioxide
4. Trap sunlight

Q. When exposed to sulphur dioxide gas, the green colour of the plant leaves will be changed into ___________.

1. Violet
2. Indigo
3. Red
4. Yellow