Question

How many types of cells are found in living organisms?

Answer 1

Cells are the basic unit of life. In the modern world, they are the smallest known world that performs all of life’s functions. All living organisms are either single cells, or are multicellular organisms composed of many cells working together. The cells are of two types: prokaryotic and eukaryotic.

• Prokaryotes: Prokaryotes are the simpler and older of the two major types of cells. Prokaryotes are single-celled organisms. Prokaryotic cells have a cell membrane, and one or more layers of additional protection from the outside environment. Many prokaryotes have a cell membrane made of phospholipids, enclosed by a cell wall made of a rigid sugar. The cell wall may be enclosed by another thick “capsule” made of sugars. Many prokaryotic cells also have cilia, tails, or other ways in which the cell can control its movement. Prokaryotic cells have a single chromosome which contains all of the cell’s essential hereditary material and operating instructions. This single chromosome is usually round. There is no nucleus, or any other internal membranes or organelles. The chromosome just floats in the cell’s cytoplasm.
• Eukaryotes: Eukaryotic cells are thought to be the most modern major cell type. Eukaryotic cells usually have more than one chromosome, which contains large amounts of genetic information. Eukaryotic cells also have one or more internal membranes, which has led scientists to the conclusion that eukaryotic cells likely evolved when one or more types of prokaryote began living in symbiotic relationships inside of other cells.