- What is? - http://www.qwhatis.com -
What is a Cell?
Posted By Erwin Z On March 15, 2011 @ 11:09 am In Biology | No Comments
What is a Cell?
A cell is the smallest and most fundamental unit of all living organisms like plants and animals. It is made up of atoms which have specific functions and carry all the necessary nutrients for the living organism to function normally. Some living organisms contain only one cell. Bacteria are an example of a unicellular organism. Other living things, such as humans and animals, are said to be multi-cellular; meaning they are composed of many cells.
There are two basic types of cells: prokaryotic and eukaryotic cells. Prokaryotic cells are those that do not have any nucleus. Examples of these cells are bacteria, which are also unicellular living organisms. Bacteria usually form in filaments or in a mass of cells. Individual cells are usually formed adjacent to each other but usually there is no connection between them. These cells can survive in almost any place on earth. Eukaryotic cells meanwhile are those that that have nuclear membranes. Examples of this type of cells are animals, plants, and fungi. They differ from prokaryotic types in terms of size and volume. Eukaryotic cells are commonly bigger and more numerous. These types of cells contain organelles in the nuclear membrane which perform specific metabolic functions. The nucleus also contains the DNA of the living organism which serves as its genetic blueprint.
Cells have different parts in terms of structure. One common part in cells is their plasma membrane. This serves as the cell’s outer covering and is composed of lipids and proteins. The inner part of the cell is called a cytoplasm, which has a fluid-like consistency. It is in this part that the organelles of eukaryotic cells reside. Another part of a cell is the cytoskeleton which functions to maintain the shape of the cell. It also helps in the arrangement of organelles within the cytoplasm. The most important part of eukaryotic cells is the nucleus, which contains the living organism’s chromosomes, DNA, and RNA. Outside the nucleus are the various organelles which have various functions necessary for metabolic activity.
Article printed from What is?: http://www.qwhatis.com
URL to article: http://www.qwhatis.com/what-is-a-cell/
Copyright © 2011 Whatis-it.net. All rights reserved.