2025年1月6日 · A cell, in biology, is the basic membrane-bound unit that contains the fundamental molecules of life and of which all living things are composed. A single cell may be a complete organism in itself, such as a bacterium, or it may acquire a specialized function, becoming a building block of a multicellular organism.

2025年2月10日 · 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.

2025年2月13日 · The molecules of cells. The structure of biological molecules; Coupled chemical reactions. Photosynthesis: the beginning of the food chain; ATP: fueling chemical reactions; The genetic information of cells. DNA: the genetic material; RNA: replicated from DNA; The organization of cells. Intracellular communication; Intercellular communication

Ependymal cell, type of neuronal support cell (neuroglia) that forms the epithelial lining of the ventricles (cavities) in the brain and the central canal of the spinal cord. Ependymal cells also give rise to the epithelial layer that surrounds the choroid plexus, a network of blood vessels located

2025年1月19日 · A stem cell is 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).

Schwann cell, any of the cells in the peripheral nervous system that produce the myelin sheath around neuronal axons. These cells are equivalent to a type of neuroglia called oligodendrocytes, which occur in the central nervous system.

2024年12月31日 · egg, in biology, the female sex cell, or gamete. In botany, the egg is sometimes called a macrogamete. In zoology, the Latin term for egg, ovum , is frequently used to refer to the single cell, while the word egg may be applied to the entire specialized structure or capsule that consists of the ovum, its various protective membranes, and any ...

2025年1月15日 · White blood cell, cellular component of blood that helps defend the body against infection. White blood cells defend against infection and disease by ingesting foreign materials and cellular debris, by destroying infectious agents and cancer cells, or by producing antibodies.

Most cells have three main parts—the cell membrane, the cytoplasm, and the nucleus. The cell membrane is like the skin of the cell. The cytoplasm performs many functions to keep the cell alive.

2025年1月27日 · Cardiac muscle cells form a highly branched cellular network in the heart. They are connected end to end by intercalated disks and are organized into layers of myocardial tissue that are wrapped around the chambers of the heart.