Question

Write short note on the following:
(a) Golgi apparatus
(b) Mitochondria

Answer 1

Mitochondria -
Mitochondria are double membraned structures i.e. they are enclosed by double membranes. The outer membrane is porous while the inner membrane is deeply folded. These folds are called cristae. They have their own DNA and proteins and hence are semi-autonomous in nature. It performs various kinds of functions like -

• produce energy (in the form of ATP) required for the functioning of cells
• regulate free calcium ion concentration in cytosol
• participate in apoptosis or programmed cell death
• provide intermediates for the synthesis of various chemicals such as fatty acids, steroids and amino acids

Golgi apparatus -
It consists of a system of membrane-bound vesicles arranged approximately parallel to each other in stacks of cisternae. It is usually composed of five−eight stacks of cisternae. Vesicles leave the Golgi body from the end known as the cis face. The other end is known as the trans face. Plant cells contain many freely distributed subunits of the Golgi apparatus, called dictyosomes. It performes functions like

• transport of lipids in cells
• formation of lysosomes
• takes part in glycosylation and phosphorylation of certain proteins