Dec 1, 2025 · What is a cell? A cell is a mass of cytoplasm that is bound externally by a cell membrane. Usually microscopic in size, cells are the smallest structural units of living matter and compose all …

Cell theory, developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells, that cells are the fundamental unit of structure and …

Jun 14, 2025 · Explore the structure, types, and functions of cells in this student-friendly guide to cell biology and cell theory.

Apr 7, 2025 · At the most fundamental level, a cell consists of a cell membrane, cytoplasm, and genetic material (DNA or RNA). The cell membrane is a semi-permeable barrier that regulates the passage …

Apr 27, 2017 · Cells are the smallest known unit that can accomplish all of these functions. Defining characteristics that allow a cell to perform these functions include: A cell membrane that keeps the …

Jul 23, 2025 · Every cell is made up of cytoplasm that is enclosed in a membrane and includes many small molecules of nutrients and metabolites as well as many macromolecules including proteins, …

Feb 22, 2021 · Cells are the basic building blocks of all living things. The human body is made of trillions of cells that carry out specialized functions.

Cells share many common features, yet they can look wildly different. In fact, cells have adapted over billions of years to a wide array of environments and functional roles.

2 days ago · All cells can be sorted into one of two groups: eukaryotes and prokaryotes. A eukaryote has a nucleus and membrane-bound organelles, while a prokaryote does not. Plants and animals are …

Oct 15, 2025 · A cell is the smallest living organism and the basic unit of life on earth. Together, trillions of cells make up the human body.