Chloroplast dimorphism is a characteristic feature ofa)C4plantsb)All plantsc)Only in algaed)Plants with the Calvin cycleCorrect answer is option 'A'. Can you explain this answer?

Question

Chloroplast dimorphism is a characteristic feature of&#8203;a)C4plantsb)All plantsc)Only in algaed)Plants with the Calvin cycleCorrect answer is option 'A'. Can you explain this answer?

Answer

The leaves of C4 plants have a characteristic anatomy consisting of concentric bundle sheath and mesophyll cell layers around the vascular bundles. These two distinct cell layers possess chloroplasts which have either structural or size dimorphism.

Answer

The term, chloroplast dimorphism means the exhistance of two distinct forms of chloroplast in same plant/ individual parts.

The variations may be found in the shape and size or in some chemical constiuents of mesophyll cloroplast and epidermal/ or bundle sheath cchloroplast. It is found in C4 plants

Answer

Chloroplast dimorphism is a characteristic feature of C4 plants.

Explanation:
C4 plants are a group of plants that have evolved a specialized mechanism to minimize photorespiration and enhance photosynthetic efficiency in hot and dry environments. One of the key features of C4 plants is the presence of chloroplast dimorphism, which refers to the differentiation of chloroplasts into two distinct types.

1. What is chloroplast dimorphism?

Chloroplast dimorphism involves the presence of two types of chloroplasts in the cells of C4 plants: mesophyll chloroplasts and bundle sheath chloroplasts.

- Mesophyll chloroplasts: These chloroplasts are located in the mesophyll cells, which are the outermost layer of cells in the leaf. Mesophyll chloroplasts are responsible for the initial capture of light energy and the fixation of carbon dioxide through the process of photosynthesis.

- Bundle sheath chloroplasts: These chloroplasts are located in the bundle sheath cells, which are the inner layer of cells surrounding the vascular tissue in the leaf. Bundle sheath chloroplasts are responsible for the further fixation of carbon dioxide and the synthesis of carbohydrates.

2. Why do C4 plants have chloroplast dimorphism?

The presence of chloroplast dimorphism in C4 plants is essential for the efficient functioning of the C4 pathway, also known as the Hatch-Slack pathway. This pathway allows C4 plants to overcome the limitations of the traditional C3 pathway, which is more susceptible to photorespiration.

- The mesophyll chloroplasts capture carbon dioxide and convert it into a four-carbon compound called oxaloacetate through the action of the enzyme phosphoenolpyruvate carboxylase (PEPcase).

- The four-carbon compound is then transported to the bundle sheath cells, where it is decarboxylated to release carbon dioxide, which is then fixed by the enzyme RuBisCO in the Calvin cycle.

- The bundle sheath chloroplasts have a higher concentration of RuBisCO and other enzymes involved in the Calvin cycle, making them more efficient in fixing carbon dioxide and synthesizing carbohydrates.

3. Significance of chloroplast dimorphism in C4 plants

The differentiation of chloroplasts into mesophyll and bundle sheath types allows C4 plants to spatially separate the initial capture of carbon dioxide from its fixation. This separation minimizes the competition between oxygen and carbon dioxide for the active site of RuBisCO, reducing the occurrence of photorespiration and enhancing photosynthetic efficiency.

In conclusion, chloroplast dimorphism is a characteristic feature of C4 plants. It plays a crucial role in facilitating the C4 pathway and enhancing the photosynthetic efficiency of these plants in hot and dry environments.

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