Name the CO 2 acceptor in the mesophyll cells during HSK pathway.

The Hatch-Slack pathway (HSK) is also called the C 4 cycle in which the first stable product is a 4 carbon compound, oxaloacetic acid. This cycle is present in most of the monocot plants in which two types of photosynthetic cells found in their leaves, i.e, mesophyll cells and bundle sheath cells. In the C 4 cycle, carbon dioxide from the environment reaches to mesophyll cells of the leaf through stomata. This carbon dioxide absorbed by phosphoenolpyruvic acid (PEP) and in the presence of the PEP Carboxylase enzyme, converts it into oxaloacetic acid. Hence, the CO 2 acceptor in the mesophyll cells during HSK pathway is phosphoenolpyruvic acid (PEP).

Why is phorespiration avoided in C 4 plants?

Photorespiration is the process of oxidation that is initiated in the chloroplast and takes place only during the day. RuBisCO, the enzyme required for CO 2 fixation in the Calvin cycle, is responsible for the photorespiration. The active site of the enzyme RuBisCO can bind to both CO 2 and O 2 . In C 4 plants, a special anatomical feature is seen, called Kranz anatomy. The large bundle sheath cells are arranged in two or three layers around the vascular bundles. Two types of chloroplast are found in C 4 plants, the chloroplast present in mesophyll cell is small and has well-developed grana while the chloroplast found in bundle sheath cell is large and without grana. Thylakoids are found in the form of stroma lamellae. Hence, in C 4 plants, the light reaction takes place in mesophyll cells. In C 4 plants, PEP carboxylase (PEPCase) enzyme catalyses the carboxylation and fixes CO 2 at low concentration in the mesophyll cells. In the bundle sheath cells, CO 2 concentration is more hence, RuBisCO functions as carboxylase, and photorespiration is avoided.

Give any two examples of C 4 plants.

The C 4 cycle is also called Hatch-Slack pathway in which the first stable product is a 4 carbon compound, oxaloacetic acid. This cycle is present in most of the monocot plants in tropical region in which two types of photosynthetic cells found in their leaves, i.e, mesophyll cells and bundle sheath cells. Examples: Maize, sugarcane, millet, sorghum, etc.

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Kranz anatomy can be seen in

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Important Questions on Photosynthesis in Higher Plants

EASY

Biology>Plant Physiology>Photosynthesis in Higher Plants>Hatch and Slack Pathway

What is the role of large bundle shealth cells found around the vascular bundles in

C_{4}

plants?

MEDIUM

Biology>Plant Physiology>Photosynthesis in Higher Plants>Hatch and Slack Pathway

Assertion (A): Relative concentration of O₂and CO₂ determines which of the two will bind to

RuBisCO .

Reason (R):

RuBisCO

has a much greater affinity for CO₂ than for O₂.
The correct option among the following is:

MEDIUM

Biology>Plant Physiology>Photosynthesis in Higher Plants>Hatch and Slack Pathway

Choose the incorrect statement from the following:

EASY

Biology>Plant Physiology>Photosynthesis in Higher Plants>Hatch and Slack Pathway

Name the CO₂ acceptor in the mesophyll cells during HSK pathway.

HARD

Biology>Plant Physiology>Photosynthesis in Higher Plants>Hatch and Slack Pathway

A plant in your garden avoids photorespiratory losses, has improved water use efficiency, shows high rates of photosynthesis at high temperatures and has improved efficiency of nitrogen utilization. In which of the following physiological groups would you assign this plant?

HARD

Biology>Plant Physiology>Photosynthesis in Higher Plants>Hatch and Slack Pathway

To avoid photorespiration, which anatomical peculiarities are shown by C₄ plants?

MEDIUM

Biology>Plant Physiology>Photosynthesis in Higher Plants>Hatch and Slack Pathway

Choose the correct option for the given figure and the “a” part highlighted in it.

Question Image

MEDIUM

Biology>Plant Physiology>Photosynthesis in Higher Plants>Hatch and Slack Pathway

What is the primary acceptor of CO₂in C₄plants? What is the first compound formed as a result of primary carboxylation in the C₄ pathway?

MEDIUM

Biology>Plant Physiology>Photosynthesis in Higher Plants>Hatch and Slack Pathway

In the maize plant,

{CO}_{2}

fixation occurs in both mesophyll and bundle sheath cells. The enzymes involved in these cells for the process respectively are

EASY

Biology>Plant Physiology>Photosynthesis in Higher Plants>Hatch and Slack Pathway

The first stable product of

{CO}_{2}

fixation in Sorghum is:

HARD

Biology>Plant Physiology>Photosynthesis in Higher Plants>Hatch and Slack Pathway

Why is phorespiration avoided in C₄ plants?

MEDIUM

Biology>Plant Physiology>Photosynthesis in Higher Plants>Hatch and Slack Pathway

Which of the following statements is incorrect?

HARD

Biology>Plant Physiology>Photosynthesis in Higher Plants>Hatch and Slack Pathway

Give the diagrammatic representation of HSK pathway.

MEDIUM

Biology>Plant Physiology>Photosynthesis in Higher Plants>Hatch and Slack Pathway

Given below are two statements:
Statement I: The primary ${CO}_{2}$ acceptor in $C_{4}$ plants is phosphoenolpyruvate which is found in the mesophyll cells.
Statement II: Mesophyll cells of $C_{4}$ plants lack RuBisCo enzyme.
In light of the above statements, choose the correct answer from the options given below: