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Oct 31, 2024 · 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.
There are two distinct types of cells: prokaryotic cells and eukaryotic cells. Though the structures of prokaryotic and eukaryotic cells differ ( see prokaryote, eukaryote), their molecular compositions and activities are very similar.
6 days ago · The cell is the basic living unit of the human body—indeed, of all organisms. The human body consists of trillions of cells, each capable of growth, metabolism, response to stimuli, and, with some exceptions, reproduction. Although there are some 200 different types of cells in the body, these can be grouped into four basic classes.
Sep 29, 2024 · 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.
Oct 21, 2024 · 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.
Oct 30, 2024 · white blood cell, a cellular component of the blood that lacks hemoglobin, has a nucleus, is capable of motility, and defends the body against infection and disease by ingesting foreign materials and cellular debris, by destroying infectious agents and cancer cells, or by producing antibodies.
Oct 28, 2024 · Eukaryote, any cell or organism that possesses a clearly defined nucleus. The eukaryotic cell has a nuclear membrane that surrounds the nucleus, in which the well-defined chromosomes (bodies containing the hereditary material) are located. Learn more about eukaryotes in this article.
Oct 30, 2024 · Cell wall, specialized form of extracellular matrix that surrounds every cell of a plant. The cell wall distinguishes plant cells from animal cells and provides physical support and protection. Learn about the functions and chemical components of plant cell walls.
Oct 31, 2024 · Cell - Structure, Organelles, Metabolism: Like the cell membrane, membranes of some organelles contain transport proteins, or permeases, that allow chemical communication between organelles. Permeases in the lysosomal membrane, for example, allow amino acids generated inside the lysosome to cross into the cytoplasm, where they can be used for ...
Oct 30, 2024 · Membrane, in biology, the thin layer that forms the outer boundary of a living cell or of an internal cell compartment.
