Site of Photosynthesis in Plant Cells

Plant cells have a lot of differences from the cells of other organisms both in terms of structure and function. They have some special organelles that are perfectly adapted to the smooth functioning of a plant. They perform the same functions that the cells of any other animal would, in addition to some special functions which are unique to plants. Photosynthesis is such a function.

Definition of Photosynthesis

Photosynthesis is the process in which minerals and chemical substances are converted into nutrition by utilizing energy from the sun and carbon dioxide from the atmosphere. Plants can produce their food, and are therefore known as the “producers”, whereas other organisms are known as “consumers”. Photosynthesis is a complex chemical process involving lots of steps and a lot of components. Different plants have different adaptations in their bodies to facilitate photosynthesis- including the cells. A plant cell has an organelle that acts as the site of photosynthesis in plant cells.

The organelle that forms the site of photosynthesis in plant cells is known as the Chloroplast. This organelle contains a green pigment known as chlorophyll, which absorbs sunlight. It is this pigment that gives plants their characteristic green color. Some plants contain chloroplasts only in their leaves, where the leaves act as specialized sites for photosynthesis. However, if asked-“what is the site of photosynthesis in plants?”, one should say that in most cases it happens all over the body of the plant. This is because in most cases the whole of the plant is covered in cells containing chloroplasts.

Structure plant cells

Plant cells, within themselves, have different classifications and functions. From all of these, however, a basic structure of the plant cell can be outlined. Learning about this basic structure helps learn about the site of photosynthesis in plant cells.

The most characteristic feature of a plant cell is the cell wall. It is a rigid outer layer covering the whole of the cell. In plants, a cell wall is made up of substances like cellulose, lignin, pectin, etc. The main function of a cell wall is to provide rigidity to the cell and give it a fixed structure. To some extent, it filters the materials passing through it.

Another feature somewhat unique to a plant cell is the presence of large vacuoles. These vacuoles can grow up to occupy about thirty percent of a cell’s volume once it is fully matured. Vacuoles provide pressure against the cell wall, which helps in maintaining cell structure even when it is absorbing moisture.

Most of the other organelles in a cell are quite similar to animal cells- mitochondria, Golgi apparatus, ribosomes, etc. One organelle, however, is unique to plants. This organelle is the chloroplast, which forms the site of photosynthesis in plant cells.

Chloroplasts

Chloroplasts are special structures found inside plant cells. These help in the synthesis of food inside plant cells through a process known as photosynthesis. It forms the site of photosynthesis in the plant and algal cells.

Chloroplasts are elongated, disc-like structures, usually green in color. They are covered with two membranes- an outer membrane and an inner membrane. There is a third membrane inside, which is thinner in comparison. This membrane is known as the thylakoid, and it usually forms folds and turns inside the chloroplast. When seen through an electron microscope, these folds appear as discs stacked on top of each other. Chlorophyll is situated inside the thylakoid, and the space between the thylakoid and the membranes is called the stroma.

Photosynthesis

The process through which plants synthesize their nutrition is known as photosynthesis.MPhotosynthesis requires minerals and moisture extracted from the ground through roots, carbon dioxide from the atmosphere, and the energy of the sun. This energy is stored inside the plant in different forms, but in most cases, it is through leaves.

In the “light-dependent” reaction, energy from the sun turns into electrons after coming into contact with chlorophyll. These electrons form a transport chain, where the energy of the electron is harnessed to produce ATP and NADPH. Since chlorophyll molecules lose electrons in the process, they replace these electrons by taking them from water molecules, which in turn leads to the formation of oxygen.

 The “light-independent” reaction happens inside the stroma. Here, the ATP and the NADPH react with carbon dioxide to form a simple sugar known as G3P. This is then converted to other complex sugars, which are used as nutrition by the plant.

Conclusion

It is quite evident that without photosynthesis, the survival of all life on earth would have been impossible. Plants are also responsible for producing oxygen, a gas that humans need to survive. In this article, we learned about the sight of photosynthesis in plants. This complex chemical process, although taking place at a microscopic level, makes sure that all life on earth can be sustained.