6. Mitochondria and chloroplasts

These are the cells that can divide and multiply rapidly. These cells can develop into any other type of cell.

 

The embryonic stem cells are a special type of cells that can become any cell type such as the blood cell, nerve cell, muscle cell or gland cell. Hence, these cells are utilized by the scientists and doctors to prevent and cure various diseases like the spinal cord injury.

 

As learnt in the previous classes, food is an energy source for the body. Like how wood is burnt to produce stored potential energy for the production of fire to heat water, the food consumed by us is broken down to release energy that the body can use for functioning.

 

In the cells that are highly active, more mitochondria are present than in the comparatively less active cells. Hence, compared to the bone cells, the muscle cells will have high numbers of mitochondria as these are the cells responsible for the movement of bones and therefore require more energy.

Some of them are green in colour due to a green colour pigment known as chlorophyll. These green colour plastids are known as chloroplasts.

 

The chloroplasts are the cell organelles that can produce food from solar energy. Hence they are known as the producers of the cell. Only the plants that contain chloroplasts can synthesize their food through photosynthesis.

 

The animal cells lack chloroplasts in their cells. Hence they are unable to prepare their food through photosynthesis.