Describe the structure and functions of mitochondria. Write two differences in function of mitochondria and chloroplasts

(a) Structure of mitochondria: Mitochondria are tiny bodies of varying shapes and size, found in the cytoplasm. Each mitochondrion is covered by a double-membrane envelope. Outer membrane is smooth and porous while inner membrane is projected with finger-like structures, the cristae. These cristae create a large surface area for ATP-generating chemical reactions. The cristae as well as inner membrane possess small tent like particles called F1 particles or oxysomes.

The energy required for various chemical activities needed for life is released by mitochondria in the form of ATP (Adenosine triphosphate) molecules. Hence, Mitochondria are also known as the powerhouses of the cell. ATP is known as the energy currency of the cell. The body uses energy stored in ATP for making new chemical compounds and for mechanical work.

The cavity of mitochondria is filled with matrix. The mitochondrial matrix contains lipids, proteins, circular DNA and RNA.

Functions of mitochondria:

(i) Mitochondria is the site of cellular respiration or oxidation of food in a cell.

(ii) The energy, released in the form of ATP, is used by body cells to synthesise new chemical compounds and to carry out other metabolic activities.

(b) Differences in function of mitochondria and chloroplasts: