Kloroplastlarn

Kloroplastlarn, commonly known as chloroplasts in English, are organelles in the cells of plants and many algae that carry out photosynthesis. They are enclosed by a double membrane and contain the stroma, an internal fluid, and an internal system of thylakoid membranes organized into stacks called grana. The thylakoids harbor chlorophyll and other pigments that capture light energy.

Primary function is to convert light energy into chemical energy by synthesizing glucose from carbon dioxide and water, with oxygen released as a byproduct. In addition to photosynthesis, chloroplasts participate in amino acid and fatty acid synthesis and in the storage of starch in the stroma.

Chloroplasts contain their own circular DNA and ribosomes, making them semi-autonomous. They replicate by fission and can move within the cell in response to light. The number and size of chloroplasts vary by tissue and species.

Origin-wise, chloroplasts are believed to be descendants of free-living cyanobacteria that formed a symbiotic relationship with early eukaryotic cells (endosymbiotic theory).

Chloroplasts are a type of plastid; other plastids include chromoplasts (pigment synthesis) and leucoplasts (starch storage). In non-photosynthetic plant tissues or parasitic plants, chloroplasts may be reduced to non-photosynthetic forms.

Chloroplasts are essential for life on Earth, providing the oxygen we breathe and forming the base of many food chains. In agriculture, their function underpins crop growth and yield.