Facts About Chloroplasts

Shape, Size, and Amount

• Chloroplasts are usually about 4 to 6 micrometers in diameter and have an oval shape, similar to that of a satellite dish. The concave side of the chloroplast faces towards the light. The shape and alignment maximizes the light-capturing ability of the chloroplast. Depending on the species of the plant, there can be about 200 chloroplasts in a single cell.

Where Are They?

• Chloroplasts exist in almost all green plant structures, such as unripened fruit and plant stems, as well as the leaves of plants. The density of chloroplasts on a surface of a leaf is approximately one-half million per square millimeter.

Cell Structure Facts

• Knowing facts about cell structure can help you understand each part of a chloroplast and its purpose. The chloroplast consists of two membranes, including the outer and inner membrane, which helps protect the inner structure of the chloroplast. The stroma is inside the chloroplast and is where sugars are created. The thylakoid or granum contains molecules of chlorophyll which use sunlight to create the sugar. The sacs are connected by stromal lamellae, which act like a skeleton and keep the sacs at a distance from one another. The cell structure of a chloroplast helps to maintain its efficiency in converting sunlight to sugars.

Purpose of Chloroplasts

• Chloroplasts exist to make sugars and starches through a process called photosynthesis. Photosynthesis occurs when a plant takes energy from sunlight to create sugars. When energy hits chloroplasts, chlorophyll takes the energy and combines carbon dioxide and water. Chloroplasts help create sugar and oxygen which are used by plants and animals. Chloroplasts are also essential in the process of producing oils, fats and proteins.