deoxyribonucleic acid, a self-replicating material present in nearly all living organisms as the main constituent of chromosomes. It is the carrier of genetic information.

any of a number of organized or specialized structures within a living cell.

Microorganisms made up of a single cell that has no distinct nucleus.

the material or protoplasm within a living cell, excluding the nucleus.

the semipermeable membrane surrounding the cytoplasm of a cell.

a rigid layer of polysaccharides lying outside the plasma membrane of the cells of plants, fungi, and bacteria. In the algae and higher plants, it consists mainly of cellulose.