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Adv. Bio Sem 2
Term | Definition |
---|---|
Carbohydrate | A sugar (monosaccharide) or one of its dimers (disaccharides) or polymers (polysaccharides). |
Gene | A discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA (or RNA, in some viruses). |
Enzyme | A macromolecule serving as a catalyst, a chemical agent that increases the rate of a reaction without being consumed by the reaction. Most enzymes are proteins. |
Lipid | Any of a group of large biological molecules, including fats, phospholipids, and steroids, that mix poorly, if at all, with water. |
Nucleic Acid | The base pairing of one strand of a nucleic acid to the complementary sequence on a strand from another nucleic acid molecule. |
DNA | A nucleic acid molecule, usually a double-stranded helix, in which each polynucleotide strand consists of nucleotide monomers with a deoxyribose sugar and the nitrogenous bases adenine (A), cytosine (C), guanine (G), and thymine (T) |
Protein | A biologically functional molecule consisting of one or more polypeptides folded and coiled into a specific three-dimensional structure. |
Amino Acid | An organic molecule possessing both a carboxyl and an amino group. Amino acids serve as the monomers of polypeptides. |
Cytosol | The semifluid portion of the cytoplasm. |
Prokaryotic Cell | A type of cell lacking a membrane-enclosed nucleus and membrane-enclosed organelles. |
Eukaryotic Cell | A type of cell with a membrane-enclosed nucleus and membrane-enclosed organelles. |
Organelle | Any of several membrane-enclosed structures with specialized functions, suspended in the cytosol of eukaryotic cells. |
Chromosome | A cellular structure consisting of one DNA molecule and associated protein molecules. |
Active Transport | The movement of a substance across a cell membrane against its concentration or electrochemical gradient, mediated by specific transport proteins and requiring an expenditure of energy. |
Electrochemical Gradient | The diffusion gradient of an ion, which is affected by both the concentration difference of an ion across a membrane (a chemical force) and the ion’s tendency to move relative to the membrane potential (an electrical force). |
Hypertonic | Referring to a solution that, when surrounding a cell, will cause the cell to lose water. |
Hypotonic | Referring to a solution that, when surrounding a cell, will cause the cell to take up water. |
Isotonic | Referring to a solution that, when surrounding a cell, causes no net movement of water into or out of the cell. |
Osmosis | The diffusion of free water across a selectively permeable membrane. |
Metabolism | The totality of an organism’s chemical reactions, consisting of catabolic and anabolic pathways, which manage the material and energy resources of the organism. |
Endergonic Reaction | A nonspontaneous chemical reaction in which free energy is absorbed from the surroundings. |
Exergonic Reaction | A spontaneous chemical reaction in which there is a net release of free energy. |
Free Energy | The portion of a biological system’s energy that can perform work when temperature and pressure are uniform throughout the system. |
Active Site | The specific region of an enzyme that binds the substrate and that forms the pocket in which catalysis occurs. |
Oxidation | The complete or partial loss of electrons from a substance involved in a redox reaction. |
Reduction | The complete or partial addition of electrons to a substance involved in a redox reaction. |
Electron Transport Chain | A sequence of electron carrier molecules (membrane proteins) that shuttle electrons down a series of redox reactions that release energy used to make ATP. |
Chemiosmosis | An energy-coupling mechanism that uses energy stored in the form of a hydrogen ion gradient across a membrane to drive cellular work, such as the synthesis of ATP. |
Glycolysis | A series of reactions that ultimately splits glucose into pyruvate. |
Fermentation | A catabolic process that makes a limited amount of ATP from glucose (or other organic molecules) without an electron transport chain and that produces a characteristic end product, such as ethyl alcohol or lactic acid. |