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 …

2025年1月14日 · 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 …

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 …

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 …

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 …

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 …

2024年11月24日 · Cell biology is the study of cells—the fundamental units of structure and function in living organisms. Cells were first observed in the 17th century, when the compound …

membrane, in biology, the thin layer that forms the outer boundary of a living cell or of an internal cell compartment. The outer boundary is the plasma membrane, and the compartments …

2025年1月15日 · Cell membrane, thin membrane that surrounds every living cell. The cell membrane functions as a barrier, keeping cell constituents in and unwanted substances out, …

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 …