Active Transport- Membrane transport processes for which ATP is required. Also refers to solute pumping.
Anabolism- Energy requiring building phase of metabolism in which simpler substances are combined to form more complex substances.
Anticodon- The three base sequence complementary to the messenger RNA codon.
Aerobic- Requiring oxygen.
Anaerobic- Not requiring oxygen.
Catabolism- Process in which living cells breakdown substances into smaller substances.
Centriole- Minute body found near the nucleus of the cell; active in cell division.
Centrosome- A region near the nucleus which contains paired organelles and centrioles.
Chromatin- Structures in the nucleus that carry the hereditary factors (genes).
Chromosome- Bar-like bodies of tightly coiled chromatin. Visible during cell division.
Cilia- Tiny, hairlike projection on cell surfaces that move in a wavelike manner.
Krebs cycle- Aerobic metabolic pathway occurring within mitochondria, in which food metabolites are oxidized and Co2 is liberated, and coenzymes are reduced. Also called the citric acid cycle.
Codon- The three-base sequence on a messenger RNA molecule that provides the genetic information used in protein synthesis, code given for an amino acid.
Cytoplasm- The cellular material surrounding the nucleus and enclosed by the plasma membrane.
Chemiosmosis- The movement of ions across a selectively permeable membrane, down their electrochemical gradiant. Relates to the generation if ATP by the movement if hydrogen ions across a membrane during cellular respiration.
Dehydrogenase- An enzyme that catalyzes the removal of hydrogen from a substrate and the transfer of the hydrogen to an acceptor in an oxidation reduction reaction.
Desmosome- Cell junction composed of thickened plasma membrane joined by filaments.
Diffusion- The spreading of particles in a gas or solution with a movement torward uniform distribution of particles; driven by kinetic energy.
Electron transport- The transfer of electrons from one carrier molecule, as a flavoprotein or a cytochrome to another along the respiratory chain and ultimately to oxygen during the aerobic production of ATP
Endocytosis- Means by which fairly large extracellular molecules or particles enter cells; eg phagocytosis, pinocytosis, receptor mediated endocytosis.
Endoplasmic reticulum- Membranous network of tubular or saclike channels in the cell.
Endothermic- A process or reaction in which the system absorbs energy from its surroundings in the form of heat.
Exocytosis- Mechanism by which substances are moved from the cell interior to the extracellular space as a secretory vesicle fuses with the plasma membrane.
Exothermic- A process or reaction that releases energy from the system, usually in the form of heat
Facilitated Transport- A form of passive transport in which materials are moved across the plasma membrane by a transport protein down their concentration gradient; hence it does not require energy.
Filtration- The act or process of filtrating, especially the process of passing a liquid or gas, such as air, through a filter in order to remove solid particles.
Flagella- A long lashlike appendage that serving as an organ of locomotion.
Gap Junction- A passageway between two adjacent cells; formed by transmembrane proteins called connexons.
Glycocalyx- A layer of externally facing glycoproteins on a cell’s plasma membrane that determines blood type; involved in the cellular interactions of fertilization, embryonic development, and immunity, and acts as an adhesive between cells.
Glycolysis- Breakdown of glucose to pyruvic acid (an anaerobic process)
Golgi apparatus- Membranous system close to the cell nucleus that packages protein secretions for export; packages enzymes into lysosomes for cellular use, and modifies proteins destined to become part of cellular membranes.
Hypertonic- Excessive, above normal, tone or tension
Hypotonic- Below normal tone or tension.