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cell, in biology, the basic membrane-bound unit that contains the fundamental molecules of life and of which all living things are composed. A single cell is often a complete organism in itself, such as a bacterium or yeast. Other cells acquire specialized functions as they mature.
Cell theory, fundamental scientific theory of biology according to which cells are held to be the basic units of all living tissues. First proposed by German scientists Theodor Schwann and Matthias Jakob Schleiden in 1838, the theory that all plants and animals are made up of cells marked a great.
cell, In biology, the basic unit of which all living things are composed; the smallest structural unit of living matter that is able to function independently. A single cell can be a complete organism in itself, as in bacteria and protozoans .
Cell membrane, thin membrane that surrounds every living cell. The cell membrane functions as a barrier, keeping cell constituents in and unwanted substances out, and as a gate, allowing transport into the cell of essential nutrients and movement from the cell of waste products.
Every organism, or living thing, is made up of structures called cells. The cell is the smallest unit with the basic properties of life. Some tiny organisms, such as bacteria and yeast, consist of only one cell. Large plants and animals have many billions of cells.
Stem cell, an undifferentiated cell that can divide to produce some offspring cells that continue as stem cells and some cells that are destined to differentiate (become specialized). Stem cells are an ongoing source of the differentiated cells that make up the tissues and organs of animals and plants.
Cellular respiration, the process by which organisms combine oxygen with foodstuff molecules, diverting the chemical energy in these substances into life-sustaining activities and discarding, as waste products, carbon dioxide and water. It includes glycolysis, the TCA cycle, and oxidative phosphorylation.
A plant cell is the basic unit of all plants. Plant cells, like animal cells, are eukaryotic, meaning they have a membrane-bound nucleus and organelles. Their characteristic cell wall is composed of cellulose, and they contain chloroplasts for photosynthesis.
Mitosis, a process of cell duplication, or reproduction, during which one cell gives rise to two genetically identical daughter cells. Strictly applied, the term is used to describe the duplication and distribution of chromosomes, the structures that carry the genetic information.
Cell - Structure, Organelles, Metabolism: Like the cell membrane, membranes of some organelles contain transport proteins, or permeases, that allow chemical communication between organelles.