What are chloroplasts?

Chloroplasts are organelles 5-10 um in size in green plants which perform the function of photosynthesis.

This is the process by which carbon dioxide and water are converted into organic chemicals using light as a source of energy. Oxygen is produced as a very useful by-product of the reaction.

The word chloroplast is derived from the Greek words, “chloros" meaning "green" and "plastes" meaning "the one who forms".

Chloroplasts are organelles bounded by a double membrane – this separates the contents of the chloroplast from the rest of the cell, allowing the photosynthetic reactions to take place without interference from chemicals in the cytoplasm.

The smooth outer membrane and an inner membrane of chloroplasts folded into disc-shaped sacs called thylakoids. Color and label the outer membrane light green. Thylakoids containing chlorophyll and other accessory pigments (red+ orange+ yellow+brown), are in stacks called granum (grana, plural).

These structures are mainly located in the palisade parenchyma of the mesophyll cells in the leaf. Chloroplasts belong to a family of specialized organelle called the plastid. The stem, leaves, and unripened fruit in all the plants contain chloroplast. But leaves are major part of plants performing the process of photosynthesis.

Plate-like membranes, called lamellae (thylakoids) run along the length of the chloroplast from end to end – these are the site of the light-dependent reactions. Chlorophyll molecules (and other pigment molecules) that absorb light energy are situated on the lamellae.

Chloroplasts like mitochondria are evolved by endosymbiosis. Both chloroplasts and mitochondria are involved in generating metabolic energy. Both organelles have their own genetic systems. During photosynthesis, the conversion of light energy derived from sunlight is converted into chemical energy in the form of carbohydrate sand during this process ATPs are generated.

Adenosine triphosphate (ATP) is the energy molecule used by all cells to do work. It isa nucleotide consisting of a nitrogen-containing base (adenine, thymine, cytosine, or guanine),a 5-carbon sugar, and 3-phosphate groups. ATP is able to store and transport chemicalenergy within cells.
What are chloroplasts?

Chlorophylls

Chlorophyll plays an important role in making plants green and healthy. Chlorophyll is found in the mesosomes of cyanobacteria and in the chloroplasts of algae and plants. This nutrient is present in green vegetables , cyanobacteria, and algae. The greener the vegetable is, the higher its chlorophyll content.

Chlorophyll’s function in a plant is to absorb light—normally sunlight. The energy absorbed from light is transferred to two kinds of energy-storing molecules. Through photosynthesis, the plant uses the stored energy to convert carbon dioxide (absorbed from the air) and water into glucose, a type of sugar.

In plants, photosynthesis takes place in chloroplasts, which contain the chlorophyll. Chloroplasts are surrounded by a double membrane and contain a third inner membrane, called the thylakoid membrane.

Plants that use photosynthesis to make their own food are called autotrophs. Animals that eat plants or other animals are called heterotrophs.

There are two types of chlorophyll in plants: chlorophyll a and chlorophyll b. All plants contain either one of these two varieties. They are both fat-soluble compounds that have antioxidant properties.
Chlorophylls