The green chloroplasts give plants their color.

Purpose

A chloroplast is a large, complex double membraned organelle that performs the function of photosynthesis within plant cells. Chloroplasts is an example of a plant plastid.

Function

Undoubtedly the most important part of the plant cell (to humans, at least), the chloroplasts are the organelles that perform photosynthesis. These cells, using the photosynthetic chlorophyll pigment, take sunlight, H2O (water) and CO2 (carbon dioxide) to produce C6H12O6 (glucose, a simple sugar) and O2 (oxygen). These organelles preform the exact opposite function of the mitochondria, which take in glucose and oxygen to produce water, carbon dioxide, and ATP (chemical energy). In short, they take minerals found in the soil and air around them, and provide them with sunlight to make substances that the cell can process.

The chloroplasts do not produce energy for the cell. Through the process of photosynthesis, they produce the raw materials that the mitochondria use to produce energy in process of cellular respiration.

Interesting note: The chloroplasts are one of the things that is used to differentiate between plant and animal; that is, only plants have them.

Another interesting note: Like the mitochondria the chloroplasts are their own individual mini-cells. They have their own DNA and ribosomes and reproduce by splitting in half.

Location

The chloroplasts can be found anywhere in the cytoplasm, though usually they are shoved up against the cell membrane by the vacuole which occupies the center of the cell.