Plant Cell Organelle: Chloroplast

What organelle is only found in plant cells? It is the chloroplast! This green pigmented organelle is exclusive to plant cells and plays a vital role in a plant's life. Chloroplast, like other organelles, has specific functions that keep the plant alive and healthy.

What Do Chloroplasts Do?

Chloroplasts are responsible for converting light energy into chemical energy through a process called photosynthesis. During this process, chloroplasts trap light energy and use it to synthesize glucose, which the plant uses as a food source. Therefore, chloroplasts are the sites of photosynthesis in the plant cell.

In addition, chloroplasts are involved in the synthesis of amino acids, lipids, and several other essential biomolecules required for the healthy growth and development of a plant.

Structure of Chloroplasts

Chloroplasts are oval-shaped organelles, usually 5-10渭m in length and 2-3 渭m in diameter. They are made up of a double membrane envelope enclosing a fluid-filled stroma, where the actual photosynthesis process occurs. Within the stroma, there are several disk-shaped thylakoids arranged in stacks, known as grana. The grana are linked together by stroma lamellae, which helps to increase the surface area available for photosynthesis.

Chloroplast Biogenesis

Chloroplasts are thought to have evolved from photosynthetic bacteria through the process of endosymbiosis. During endosymbiosis, a prokaryotic cell, like an ancestral cyanobacterium, was engulfed by a eukaryotic cell, leading to the development of an organelle, such as a chloroplast.

New chloroplasts are formed by division of pre-existing chloroplasts within the plant cell. This division, which is similar to bacterial division, leads to the creation of two smaller chloroplasts that grow and divide themselves again, forming new chloroplasts. This process also involves the reorganization of the thylakoid membranes to accommodate the growing chloroplast.

Conclusion

In summary, the chloroplast is an organelle that is exclusively found in plant cells. It plays a vital role in the life of a plant by converting light energy into chemical energy through photosynthesis. Chloroplasts have a specific structure with several disk-shaped thylakoids arranged in stacks, known as grana. Chloroplast biogenesis occurs through the process of the division of pre-existing chloroplasts within the plant cell.