CAM Pathway

Q. CAM helps the plants in __________.

1. primary growth
2. secondary growth
3. reducing loss of water by transpiration
4. transporting minerals and nutrients from the soil

Q. Select the incorrect statement about RuBisCO.

1. It is the most abundant enzyme
2. It has much greater affinity for CO${}_2$ than for O${}_2$
3. In C${}_3$ plants some O${}_2$ does bind to RuBisCO
4. RuBP combines with O${}_2$ to form 3 molecules of 3-PGA, this reaction is also catalysed by RuBisCO

Q. In a CAM-plant, the concentration of organic acid

1. Decreases or increases during the day
2. Decreases during any time
3. Increases during night
4. Increases during the day

Q. Give comparison between the following: C3 and C4 pathways

Q. Which of the following is a CAM plant?

1. Sugarcane
2. Cactus
3. Sorghum
4. Maize

Q.

In CAM-plants, carbon dioxide required for photosynthesis enters the plant body during

1. Day time throught the lenticels

2. Night, through the open stomata

3. Day time through open stomata

4. Night when the hydathodes are open

Q. Which types of plants store malic acid in vacuoles?

1. $C_3$
2. CAM
3. $C_4$
4. $C_2$

Q.

Question 47
Suppose Euphorbia and maize are grown in the tropical area.
(a) Which one of them do you think will be able to survive under such conditions?

(b) Which one of them is more efficient in terms of photosynthetic activity?

(c) What difference do you think are there in their leaf anatomy?

Q. Succulents carry out carbon fixation during photosynthesis by

1. CAM pathway
2. $C_4$ pathway
3. $C_3$ pathway
4. $C_2$pathway

Q. The first stable product of CAM cycle is

1. Pyruvic acid
2. Oxalic acid
3. Malic acid
4. Oxaloacetic acid

Q. By looking at a plant externally can you tell whether a plant is C3 or C4? Why and how?

Q. Assertion: CAM plants lack structural compartmentation of leaf as found in C4 plants.

Reason: Stomata of CAM plants are open during the day.

1. Both assertion and reason are true and reason is the correct explanation of assertion
2. Assertion is true but reason is false
3. Both assertion and reason are true but reason is not the correct explanation of assertion
4. Both assertion and reason are false

Q. Stomata are distributed more on the lower surface than on the upper surface in

1. Unifacial leaf
2. Both A and B
   
3. Equifacial leaf
4. Bifacial leaf

Q. How do potassium ions regulate the opening and closing of stomata?

Q. Absorption of mineral nutrients by a plant from the soil is a process, which is

1. Dependent on water absorption
2. Dependent on the strength of soil solution
   
3. Osmotic in principle
4. Independent of water absorption

Q.

In the following question, a statement of assertion is following by a statement of reason. Mark the correct choice as:
Assertion: CAM plants lack structural compartmentation of a leaf as found in $C_4$ plants.
Reason: Stomata of CAM plants are open during the day.

1. If both assertion and reason are true and reason is the correct explanation of assertion.

2. If both assertion and reason are true but reason is not the correct explantion are true but reason.

3. If both assertion and reason are false

4. If assertion is true but reason is false.

Q. CAM pathway operates in:

1. Drought escaping xerophytes
2. Drought resisting xerophytes
3. Flood enduring xerophytes
4. Ephemerals

Q. According to $H^{+}-K^{+}$ exchange pump mechanism of stomatal movement
I. $K^{+}$ ions accumulate in guard cells during the day.
II. $H^{+}$ ions are pumped out from guard cells and $K^{+}$ ions are pumped into guard cells.
III. Water potential of guard cells decreases with the accumulation of $K^{+}$ ions together with $C{l}^{-}$ and organic acid ions.
IV. Water enters into guard cells from epidermal and mesophyll cells due to decreased water potential of guard cells.

1. I, II and IV are correct
2. I and II are correct
3. All are correct
4. II, III and IV are correct

Q. In a CAM-plant, the concentration of organic acid

1. Increases during the day
2. Decreases or increases during the day
3. Increases during night
4. Decreases during any time

Q. The first stable product in CAM/C4 plants is

1. Starch
2. Oxaloacetic acid
3. Sugar
4. Malic acid.

Q. Glycolate induces opening of stomata in

1. Presence of oxygen
2. Low CO${}_2$ concentration
3. High CO${}_2$ concentration
4. Absence of CO${}_2$

Q. Assertion :Tropical plants have a higher optimum temperature for photosynthesis than temperate plants. Reason: The temperature optimum for photosynthesis of different plants depends on their habitat.

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. Both Assertion and Reason are incorrect

Q. What is correct for $C_4$ plant ?

1. $C{O}_2$ combines with PGA
2. $C{O}_2$ combines with PGAL
3. $C{O}_2$ combines with RuBP
4. $C{O}_2$ combines with PEP

Q. Which of the following occurs in the CAM pathway during the night?

1. $C{O}_2$ is released which is used in the Calvin cycle
2. Malic acid is stored in the vacuole
3. Malic acid is converted to malate
4. Malate is converted to phosphoenolpyruvate

Q. ________ is the first stable product produced during night time in CAM plants.

1. Oxaloacetate
2. Malate
3. 3-phosphoglycerate
4. Triose phosphate

Q. Stomata of CAM plants:

1. Are always open
2. Open during the day and close at night
3. Open during the night and close during the day
4. Never open

Q. Which of the following is a CAM plant?

1. Sorghum
2. Sugarcane
3. Cactus
4. Maize

Q. Stomata which remain closed during night and open only during the day for a few hours are of

1. Barley or cereal type
2. Alfalfa type
3. Lucerne type
4. Potato type

Q.

Which of the following is mismatched?

1. Photosystem I - uses the P700 molecule in its photocentre

2. CAM plants - open their stomata during the day and close them at night to avoid photorespiration

3. PGA - a 3-carbon compound

4. antenna complex - contains hundreds of pigment molecules

Q.

Identify incorrect statement about CAM Plants

1. CAM plants show scotoactive type of ofomata

2. CAM plants show CO₂ fixation in two kinds of cells

3. CO₂ is fixed during night and glucose is made during day

4. CO₂ fixation and calvin cycle are separated by time