Give Brief description of chloroplast ?

Chloroplasts are found in all green plants and algae. They are the food producers of plants. These are found in the guard cells located in the leaves of the plants. They contain a high concentration of chlorophyll that traps sunlight. This cell organelle is not present in animal cells.

Chloroplast has its own DNA and can reproduce independently, from the rest of the cell. They also produce amino acids and lipids required for the production of chloroplast membrane.

Structure of Chloroplast

Chloroplasts are found in all higher plants. It is oval or biconvex, found within the mesophyll of the plant cell. The size of the chloroplast usually varies between 4-6 µm in diameter and 1-3 µm in thickness. They are double-membrane organelle with the presence of outer, inner and intermembrane space. There are two distinct regions present inside a chloroplast known as the grana and stroma.

• Grana are made up of stacks of disc-shaped structures known as thylakoids. The grana of the chloroplast consists of chlorophyll pigments and are the functional units of chloroplasts.
• Stroma is the homogenous matrix which contains grana and is similar to the cytoplasm in cells in which all the organelles are embedded. Stroma also contains various enzymes, DNA, ribosomes, and other substances. Stroma lamellae function by connecting the stacks of thylakoid sacs.