Last modified: Sat 4/26/97 0430 PDT
 Canon Terms |
Object | Classes | Cell; Genome; Gene; Enzyme |
| Instances | (none) | ||
| Event | Classes | CellMetabolism; CellReproduction; GeneExpression | |
| Instances | (none) |
Cells are the simplest known Living Agents, i.e. the simplest agents known to exhibit the basic processes of life. All Living Agents which are not themselves cells are aggregates of cells. The study of cells is the subject matter of cell biology (sometimes called cytology), part of biology.
Cells are aggregates of organelles and other dependent biostructures.
A eucaryotic cell is a cell which contains a cell nucleus (a type of organelle). A procaryotic cell is a cell which lacks a nucleus.
Cell metabolism is one of the two basic processes of life in a cell.
Membrane transport is a process of cell metabolism in which material passes through a cellular membrane.
Plasma membrane transport is the process of membrane transport across the plasma membrane of a cell. This process can be active (requiring the cell to expend energy) or passive (requiring no such energy expenditure).
Vesicle-mediated transport is the type of of active plasma membrane transport in which vesicles or vacuoles containing the transported material fuse with the plasma membrane.
The process of vesicle-mediated transport is referred to as endocytosis or as exocytosis when material is being transported into or out of the cell, respectively.
The three types of endocytosis are phagoocytosis, pinocytosis and receptor-mediated endocytosis.
Phagocytosis is the type of endocytosis in which solid particles are engulfed by the vesicles.
Pinocytosis is the type of endocytosis in which fluid droplets are engulfed by the vesicles.
Receptor-mediated endocytosis is the type of endocytosis in which specific types of molecules (called ligands) are engulfed by the vesicles. The specificity of transport is controlled by the interaction of the ligand with protein molecules (called receptors) embedded in the plasma membrane.
Cellular respiration is a process of cell metabolism in which glucose and oxygen are consumed and adenosine triphosphate (ATP) and carbon dioxide are produced.
Protein synthesis is a process of cell metabolism in which a specific sequence of amino acids is constructed (polymerized), resulting in the creation of a new protein molecule. Since the amino acid sequence originates in a nucleic acid template, this process is also referred to as translation.
Photosynthesis is a process of cell metabolism in which carbon dioxide, water and the energy of light from Sol are consumed and glucose and oxygen are produced.
Cell reproduction is one of the two basic processes of life in a cell.
The processes of cell metabolism and cell reproduction are organized around a set of nucleic acid molecules referred to as the cell's genome. Specific units of the genome, called genes, contain the information necessary for the cell to construct specific protein molecules (a process called gene expression). Some of these protein molecules (referred to as enzymes) then play a pivotal role in the control of cell processes, including the process of gene expression itself. Other (non-enzymatic) proteins provide part of the material for the dependent biostructures of the cell. The study of genomes and gene expression is the subject matter of genetics, part of biology.