Term
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Definition
| information needed to code for proteins |
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Term
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Definition
| most important macromolecules with a function |
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Term
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Definition
| one of several formed bodies with specialized functions in a eukaryotic cell's cytoplasm |
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Term
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Definition
| the scientific study of life |
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Term
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Definition
| new properties that emerge with each step upward in theherarchy of life, due to the arrangement and interactions of parts as complexity increases |
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Term
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Definition
| reducing complex systems to simpler components that are more manageable to study |
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Term
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Definition
| generalizations are based on a large number of specific observations |
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Term
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Definition
| specific results are predicted from a general premise |
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Term
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Definition
| aims to model the dynamic behavior of whole biological systems |
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Term
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Definition
| using computing power, software, and mathematical models to process and integrate biological info from large data sets |
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Term
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Definition
| application of scienctific knowledge for a certain purpose |
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Term
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Definition
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Term
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Definition
| anything that takes up space and has mass |
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Term
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Definition
| any substance that can't be broken down to any other substance |
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Term
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Definition
| a subtance consisting of two or more elements in a fixed ratio |
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Term
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Definition
| the smallest unit of matter that retains the properties of an element |
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Term
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Definition
| neutral particle in the nucleus of an atom |
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Term
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Definition
| subatomic particle with a negative charge |
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Term
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Definition
| subatomc particle with a postivie charge in the nucleus of an atom |
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Term
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Definition
| a measure of mass for atoms and subatomic particles |
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Term
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Definition
| number of protons in the nucleus of an atom (subscript to the left) |
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Term
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Definition
| an energy level represented as the average distance an electron is away from the nucleus |
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Term
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Definition
| an attraction between two atoms |
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Term
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Definition
| two atoms share 1 or more valence electrons |
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Term
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Definition
| two or more atoms held together by covalent bonds |
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Term
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Definition
| molecular notation where lines represent covalent bonds bewteen atoms |
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Term
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Definition
| an atom that gained or lost electrons and therefore has a charge |
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Term
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Definition
| attraction bewteen two oppositely charged ions |
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Term
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Definition
| making and/or breaking chemical bonds, chemical chnages in matter |
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Term
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Definition
| the attraction of an atom for the electrons of a covalent bond |
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Term
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Definition
| a covalent bond between atoms that differ in electronegativity |
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Term
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Definition
| a molecule with opposite charge on opposie sides (water) |
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Term
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Definition
| a weak bond formed between a slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule |
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Term
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Definition
| the sphere of water molecules around each dissolved ion |
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Term
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Definition
| having an affinity for water |
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Term
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Definition
| having an aversion to water |
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Term
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Definition
| weak bond formed when molecules that do not mix with water coalesce to exclude the water |
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Term
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Definition
| a common measure of solute concentration, number of moles of solute per liter of solution |
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Term
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Definition
| the measure of the concentraion of hydrogen ions in solution |
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Term
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Definition
| a substance that increases the hydrogen ion concetration of a solution |
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Term
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Definition
| a substance that reduces the hydrogen ion concentration of a solution |
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Term
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Definition
| the 5' end of a pre-mRNA molecule modified by the addition of a cap of guanine nucleotide |
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Term
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Definition
| holds the tRNA carrying the next amino acid to be added to the polypeptide chain |
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Term
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Definition
| acetyl coenzyme A; the entry compound for the citric acid cycle in cellular respiration, formed from a fragment of pyruvate attached to a coenzyme |
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Term
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Definition
| the amount of energy that reactants must absorb before a chemical rxn will start |
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Term
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Definition
| the specific portion of an enzyme that attaches to the substrate by means of weak chemical bonds |
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Term
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Definition
| the movement of a substance across a membrane against its concentration or electrochemical gradient with the help of energy input and specific transport proteins |
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Term
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Definition
| A specific configuration of atoms commonly attached to the carbon skeletons of organic molecules and usually involved in chemical reactions. |
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Term
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Definition
| A functional group consisting of a hydrogen atom joined to an oxygen atom by a polar covalent bond. Molecules possessing this group are soluble in water and are called alcohols. |
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Term
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Definition
| A functional group consisting of a sulfur atom bonded to a hydrogen atom (--SH). |
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Term
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Definition
| A functional group important in energy transfer. |
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Term
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Definition
| A functional group that consists of a nitrogen atom bonded to two hydrogen atoms; can act as a base in solution, accepting a hydrogen ion and acquiring a charge of +1. |
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Term
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Definition
| A functional group present in organic acids and consisting of a single carbon atom double-bonded to an oxygen atom and also bonded to a hydroxyl group. |
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Term
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Definition
| A functional group present in aldehydes and ketones and consisting of a carbon atom double-bonded to an oxygen atom. |
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Term
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Definition
| A giant molecule formed by the joining of smaller molecules, usually by a condensation reaction. Polysaccharides, proteins, and nucleic acids are macromolecules. |
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Term
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Definition
| A long molecule consisting of many similar or identical monomers linked together |
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Term
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Definition
| The subunit that serves as the building block of a polymer. |
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Term
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Definition
| A chemical reaction in which two molecules covalently bond to each other with the removal of a water molecule. |
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Term
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Definition
| A chemical process that lyses, or splits, molecules by the addition of water. |
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Term
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Definition
| An organic molecule possessing both carboxyl and amino groups. Amino acids serve as the monomers of proteins. |
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Term
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Definition
| The covalent bond between two amino acid units, formed by a dehydration reaction. |
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Term
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Definition
| The level of protein structure referring to the specific sequence of amino acids. |
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Term
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Definition
| The localized, repetitive coiling or folding of the polypeptide backbone of a protein due to hydrogen bond formation between peptide linkages. |
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Term
| alpha helix quaternary structure |
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Definition
| A spiral shape constituting one form of the secondary structure of proteins, arising from a specific hydrogen-bonding structure |
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Term
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Definition
| One form of the secondary structure of proteins in which the polypeptide chain folds back and forth. Two regions of the chain lie parallel to each other and are held together by hydrogen bonds. |
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Term
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Definition
| Irregular contortions of a protein molecule due to interactions of side chains involved in hydrophobic interactions, ionic bonds, hydrogen bonds, and disulfide bridges. |
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Term
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Definition
| The particular shape of a complex, aggregate protein, defined by the characteristic three-dimensional arrangement of its constituent subunits, each a polypeptide. |
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Term
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Definition
| A strong covalent bond formed when the sulfur of one cysteine monomer bonds to the sulfur of another cysteine monomer. |
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Term
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Definition
| a process in which a protein unravels and loses its native conformation, thereby becoming biologically inactive. In DNA, the separation of the two strands of the double helix. Denaturation occurs under extreme conditions of pH, salt concentration, and temperature. |
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Term
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Definition
| A protein molecule that assists the proper folding of other proteins. |
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Term
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Definition
| The totality of an organism’s chemical reactions, consisting of catabolic and anabolic pathways. |
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Term
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Definition
| A series of chemical reactions that either builds a complex molecule (anabolic pathway) or breaks down a complex molecule into simpler compounds (catabolic pathway). |
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Term
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Definition
| A metabolic pathway that releases energy by breaking down complex molecules to simpler compounds. |
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Term
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Definition
| A metabolic pathway that synthesizes a complex molecule from simpler compounds. |
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Term
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Definition
| The portion of a system’s energy that can perform work when temperature and pressure are uniform throughout the system. |
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Term
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Definition
| A spontaneous chemical reaction, in which there is a net release of free energy. |
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Term
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Definition
| A non-spontaneous chemical reaction, in which free energy is absorbed from the surroundings. |
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Term
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Definition
| A protein serving as a catalyst, a chemical agent that changes the rate of a reaction without being consumed by the reaction. |
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Term
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Definition
| A chemical agent that changes the rate of a reaction without being consumed by the reaction. |
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Term
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Definition
| The reactant on which an enzyme works. |
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Term
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Definition
| A temporary complex formed when an enzyme binds to its substrate molecule |
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Term
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Definition
| The change in shape of the active site of an enzyme so that it binds more snugly to the substrate, induced by entry of the substrate. |
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Term
|
Definition
| Any non-protein molecule or ion that is required for the proper functioning of an enzyme. Cofactors can be permanently bound to the active site or may bind loosely with the substrate during catalysis. |
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Term
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Definition
| An organic molecule serving as a cofactor. Most vitamins function as coenzymes in important metabolic reactions. |
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Term
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Definition
| A substance that reduces the activity of an enzyme by entering the active site in place of the substrate whose structure it mimics. |
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Term
| non-competitive inhibitor |
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Definition
| A substance that reduces the activity of an enzyme by binding to a location remote from the active site, changing its conformation so that it no longer binds to the substrate. |
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Term
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Definition
| The binding of a molecule to a protein that affects the function of the protein at a different site. |
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Term
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Definition
| A method of metabolic control in which the end product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway. |
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Term
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Definition
| A polymer (polynucleotide) consisting of many nucleotide monomers; serves as a blueprint for proteins and, through the actions of proteins, for all cellular activities. The two types are DNA and RNA. |
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Term
|
Definition
| A discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA |
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Term
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Definition
| A type of nucleic acid consisting of nucleotide monomers with a ribose sugar and the nitrogenous bases adenine (A), cytosine (C), guanine (G), and uracil (U); usually single-stranded; functions in protein synthesis and as the genome of some viruses. |
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Term
|
Definition
| the building block of a nucleic acid, consisting of a five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group. |
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Term
|
Definition
| One of two types of nitrogenous bases found in nucleotides. Cytosine (C), thymine (T), and uracil (U) are pyrimidines. |
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Term
|
Definition
| One of two types of nitrogenous bases found in nucleotides. Adenine (A) and guanine (G) are purines. |
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Term
|
Definition
| The sugar component of RNA. |
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Term
|
Definition
| The sugar component of DNA, having one less hydroxyl group than ribose, the sugar component of RNA. |
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Term
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Definition
| A threadlike, gene-carrying structure found in the nucleus. Each chromosome consists of one very long DNA molecule and associated proteins. See chromatin. |
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Term
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Definition
| A virus that infects bacteria; |
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Term
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Definition
| The form of native DNA, referring to its two adjacent polynucleotide strands wound into a spiral shape. |
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Term
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Definition
| The opposite arrangement of the sugar-phosphate backbones in a DNA double helix. |
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Term
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Definition
| A Y-shaped region on a replicating DNA molecule where new strands are growing. |
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Term
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Definition
| Type of DNA replication in which the replicated double helix consists of one old strand, derived from the old molecule, and one newly made strand. |
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Term
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Definition
| An enzyme that catalyzes the elongation of new DNA at a replication fork by the addition of nucleotides to the existing chain. |
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Term
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Definition
| An enzyme that untwists the double helix of DNA at the replication forks. |
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Term
| single-strand binding protein |
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Definition
| During DNA replication, molecules that line up along the unpaired DNA strands, holding them apart while the DNA strands serve as templates for the synthesis of complementary strands of DNA. |
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Term
|
Definition
| A protein that functions in DNA replication, helping to relieve strain in the double helix ahead of the replication fork. |
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Term
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Definition
| The new continuous complementary DNA strand synthesized along the template strand in the mandatory 5’ ( 3’ direction. |
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Term
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Definition
| A discontinuously synthesized DNA strand that elongates in a direction away from the replication fork. |
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Term
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Definition
| A short segment of DNA synthesized on a template strand during DNA replication. Many Okazaki fragments make up the lagging strand of newly synthesized DNA. |
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Term
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Definition
| A linking enzyme essential for DNA replication; catalyzes the covalent bonding of the 3’ end of a new DNA fragment to the 5’ end of a growing chain. |
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Term
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Definition
| A polynucleotide with a free 3´ end, bound by complementary base pairing to the template strand, that is elongated during DNA replication. |
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Term
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Definition
| An enzyme that joins RNA nucleotides to make the primer. |
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Term
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Definition
| The protective structure at each end of a eukaryotic chromosome. Specifically, the tandemly repetitive DNA at the end of the chromosome’s DNA molecule. See also repetitive DNA. |
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Term
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Definition
| An enzyme that catalyzes the lengthening of telomeres. The enzyme includes a molecule of RNA that serves as a template for new telomere segments. |
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Term
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Definition
| The synthesis of RNA on a DNA template. |
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Term
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Definition
| An initial RNA transcript; also called pre-mRNA when transcribed from a protein-coding gene. |
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Term
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Definition
| Modification of RNA before it leaves the nucleus, a process unique to eukaryotes. |
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Term
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Definition
| A type of RNA, synthesized from DNA, that attaches to ribosomes in the cytoplasm and specifies the primary structure of a protein. |
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Term
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Definition
| The synthesis of a polypeptide using the genetic information encoded in an mRNA molecule. There is a change of languagefrom nucleotides to amino acids. |
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Term
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Definition
| the site of protein synthesis in the cytoplasm; consists of rRNA and protein molecules, which make up two subunits. |
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Term
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Definition
| An enzyme that links together the growing chain of ribonucleotides during transcription. |
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Term
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Definition
| A specific nucleotide sequence in DNA that binds RNA polymerase and indicates where to start transcribing RNA. |
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Term
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Definition
| The modified end of the 3’ end of an mRNA molecule consisting of the addition of some 50 to 250 adenine nucleotides. |
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Term
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Definition
| A noncoding, intervening sequence within a eukaryotic gene. |
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Term
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Definition
| A coding region of a eukaryotic gene. Exons, which are expressed, are separated from each other by introns. |
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Term
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Definition
| A complex assembly that interacts with the ends of an RNA intron in splicing RNA, releasing the intron and joining the two adjacent exons. |
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Term
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Definition
| A three-nucleotide sequence of DNA or mRNA that specifies a particular amino acid or termination signal; the basic unit of the genetic code. |
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Term
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Definition
| The most abundant type of RNA, which together with proteins forms the structure of ribosomes. Ribosomes coordinate the sequential coupling of tRNA molecules to mRNA codons. |
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Term
|
Definition
| An RNA molecule that functions as an interpreter between nucleic acid and protein language by picking up specific amino acids and recognizing the appropriate codons in the mRNA. |
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Term
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Definition
| A specialized base triplet at one end of a tRNA molecule that recognizes a particular complementary codon on an mRNA molecule. |
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Term
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Definition
| A violation of the base-pairing rules in that the third nucleotide (5’ end) of a tRNA anticodon can form hydrogen bonds with more than one kind of base in the third position (3’ end) of a codon. |
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Term
| aminoacyl-tRNA synthetase |
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Definition
| An enzyme that joins each amino acid to the correct tRNA. |
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Term
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Definition
| One of a ribosome’s three binding sites for tRNA during translation. The P site holds the tRNA carrying the growing polypeptide chain. (P stands for peptidyl tRNA.) |
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Term
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Definition
| The way a cell’s mRNA-translating machinery groups the mRNA nucleotides into codons. |
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Term
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Definition
| A stretch of amino acids on a polypeptide that targets the protein to a specific destination in a eukaryotic cell. |
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Term
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Definition
| A unit of genetic function common in bacteria and phages, consisting of coordinately regulated clusters of genes with related functions. |
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Term
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Definition
| In prokaryotic DNA, a sequence of nucleotides near the start of an operon to which an active repressor can attach. The binding of the repressor prevents RNA polymerase from attaching to the promoter and transcribing the genes of the operon. |
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Term
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Definition
| A protein that suppresses the transcription of a gene. |
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Term
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Definition
| A small molecule that cooperates with a repressor protein to switch on operon off. |
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Term
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Definition
| A specific small molecule that inactivates the repressor in an operon. |
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Term
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Definition
| A physiological control mechanism in which a change in some variable triggers mechanisms that amplify the change. |
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Term
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Definition
| A primary mechanism of homeostasis, whereby a change in a physiological variable triggers a response that counteracts the initial fluctuation. |
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Term
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Definition
| The structural and functional divergence of cells as they become specialized during a multicellular organism’s development; dependent on the control of gene expression. |
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Term
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Definition
| The complex of DNA and proteins that makes up a eukaryotic chromosome. When the cell is not dividing, chromatin exists as a mass of very long, thin fibers that are not visible with a light microscope. |
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Term
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Definition
| A small protein with a high proportion of positively charged amino acids that binds to the negatively charged DNA and plays a key role in its chromatin structure. |
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Term
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Definition
| The basic, bead-like unit of DNA packaging in eukaryotes, consisting of a segment of DNA wound around a protein core composed of two copies of each of four types of histone. |
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Term
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Definition
| The attachment of acetyl groups to certain amino acids of histone proteins. |
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Term
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Definition
| A regulatory protein that binds to DNA and stimulates transcription of specific genes. |
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Term
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Definition
| A DNA segment containing multiple control elements that may be located far away from the gene it regulates. |
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Term
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Definition
| A DNA molecule made in vitro with segments from different sources. |
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Term
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Definition
| The direct manipulation of genes for practical purposes. |
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Term
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Definition
| The manipulation of living organisms or their components to produce useful products. |
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Term
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Definition
| DNA segment resulting from cutting of DNA by a restriction enzyme. |
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Term
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Definition
| A single-stranded end of a double-stranded DNA restriction fragment. |
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Term
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Definition
| A small ring of DNA that carries accessory genes separate from those of a bacterial chromosome; also found in some eukaryotes, such as yeast. |
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Term
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Definition
| A set of thousands of DNA segments from a genome, each carried by a plasmid, phage, or other cloning vector. |
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Term
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Definition
| A DNA molecule made in vitro using mRNA as a template and the enzyme reverse transcriptase. A cDNA molecule therefore corresponds to a gene, but lacks the introns present in the DNA of the genome. |
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Term
| polymerase chain reaction (PCR) |
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Definition
| A technique for amplifying DNA in vitro by incubating with special primers, DNA polymerase molecules, and nucleotides. |
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Term
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Definition
| One of a family of compounds, including fats, phospholipids, and steroids, that are insoluble in water. |
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Term
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Definition
| A molecule that is a constituent of the inner bilayer of biological membranes, having a polar, hydrophilic head and a nonpolar, hydrophobic tail. |
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Term
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Definition
| A long carbon chain carboxylic acid. Fatty acids vary in length and in the number and location of double bonds; three fatty acids linked to a glycerol molecule form fat. |
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Term
|
Definition
| A molecule that has both a hydrophilic region and a hydrophobic region. |
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Term
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Definition
| A property of biological membranes that allows some substances to cross more easily than others. |
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Term
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Definition
| The currently accepted model of cell membrane structure, which envisions the membrane as a mosaic of individually inserted protein molecules drifting laterally in a fluid bilayer of phospholipids. |
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Term
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Definition
| Typically a transmembrane protein with hydrophobic regions that completely spans the hydrophobic interior of the membrane. |
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Term
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Definition
| A protein appendage loosely bound to the surface of a membrane and not embedded in the lipid bilayer. |
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Term
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Definition
| A steroid that forms an essential component of animal cell membranes and acts as a precursor molecule for the synthesis of other biologically important steroids. |
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Term
|
Definition
| A protein covalently attached to a carbohydrate. |
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Term
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Definition
| A transmembrane protein that helps a certain substance or class of closely related substances to cross the membrane. |
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Term
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Definition
| The movement of a substance across a biological membrane against its concentration or electrochemical gradient with the help of energy input and specific transport proteins. |
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Term
|
Definition
| The diffusion of a substance across a biological membrane. |
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Term
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Definition
| The spontaneous tendency of a substance to move down its concentration gradient from a more concentrated to a less concentrated area. |
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Term
|
Definition
| The spontaneous passage of molecules and ions, bound to specific carrier proteins, across a biological membrane down their concentration gradients. |
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Term
|
Definition
| protein channel in a cell membrane that opens or closes in response to a particular stimulus. |
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Term
|
Definition
| The diffusion of water across a selectively permeable membrane. |
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Term
|
Definition
| A transport protein in the plasma membrane of a plant or animal cell that specifically facilitates the diffusion of water across the membrane (osmosis). |
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Term
|
Definition
| In comparing two solutions, referring to the one with a greater solute concentration. |
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Term
|
Definition
| In comparing two solutions, referring to the one with a lower solute concentration. |
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Term
|
Definition
| Having the same solute concentration as another solution. |
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Term
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Definition
| Very firm. A walled cell become turgid if it has a greater solute concentration than its surroundings, resulting in entry of water. |
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Term
|
Definition
| A phenomenon in walled cells in which the cytoplasm shrivels and the plasma membrane pulls away from the cell wall when the cell loses water to a hypertonic environment. |
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Term
|
Definition
| A special transport protein in the plasma membrane of animal cells that transports sodium out of the cell and potassium into the cell against their concentration gradients. |
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Term
|
Definition
| The diffusion gradient of an ion, representing a type of potential energy that accounts for both the concentration difference of the ion across a membrane and its tendency to move relative to the membrane potential. |
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Term
|
Definition
| An ion transport protein that generates voltage across a membrane. |
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Term
|
Definition
| The coupling of the downhilldiffusion of one substance to the uphilltransport of another against its own concentration gradient. |
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Term
|
Definition
| The coupling of the downhilldiffusion of one substance to the uphilltransport of another against its own concentration gradient. |
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Term
|
Definition
| The coupling of the downhilldiffusion of one substance to the uphilltransport of another against its own concentration gradient. |
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Term
|
Definition
| The cellular secretion of macromolecules by the fusion of vesicles with the plasma membrane. |
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Term
|
Definition
| The cellular uptake of macromolecules and particulate substances by localized regions of the plasma membrane that surround the substance and pinch off to form an intracellular vesicle. |
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Term
|
Definition
| A type of endocytosis involving large, particulate substances, accomplished mainly by macrophages, neutrophils, and dendritic cells. |
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Term
|
Definition
| A type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes. |
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|
Term
| receptor-mediated endocytosis |
|
Definition
| The movement of specific molecules into a cell by the inward budding of membranous vesicles containing proteins with receptor sites specific to the molecules being taken in; enables a cell to acquire bulk quantities of specific substances. |
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|
Term
| ATP (adenosine triphosphate) |
|
Definition
| An adenine-containing nucleoside triphosphate that releases free energy when its phosphate bonds are hydrolyzed. This energy is used to drive endergonic reactions in cells. |
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Term
|
Definition
| (plural, mitochondria) An organelle in eukaryotic cells that serves as the site of cellular respiration. |
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Term
|
Definition
| The most prevalent and efficient catabolic pathway for the production of ATP, in which oxygen is consumed as a reactant along with the organic fuel. |
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Term
|
Definition
| The conversion of light energy to chemical energy that is stored in glucose or other organic compounds; occurs in plants, algae, and certain prokaryotes. |
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Term
|
Definition
| An organelle found only in plants and photosynthetic protists that absorbs sunlight and uses it to drive the synthesis of organic compounds from carbon dioxide and water. |
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Term
|
Definition
| A biological compound consisting of three fatty acids linked to one glycerol molecule. |
|
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Term
|
Definition
| A sugar (monosaccharide) or one of its dimers (disaccharides) or polymers (polysaccharides). |
|
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Term
|
Definition
| The simplest carbohydrate, active alone or serving as a monomer for disaccharides and polysaccharides. Also known as simple sugars, the molecular formulas of monosaccharides are generally some multiple of CH2O. |
|
|
Term
|
Definition
| A double sugar, consisting of two monosaccharides joined by dehydration synthesis. |
|
|
Term
|
Definition
| A polymer of up to over a thousand monosaccharides, formed by dehydration reactions. |
|
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Term
|
Definition
| A storage polysaccharide in plants consisting entirely of glucose. |
|
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Term
|
Definition
| An extensively branched glucose storage polysaccharide found in the liver and muscle of animals; the animal equivalent of starch. |
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Term
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Definition
| (plural, cristae) An infolding of the inner membrane of a mitochondrion that houses the electron transport chain and the enzyme catalyzing the synthesis of ATP. |
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| The compartment of the mitochondrion enclosed by the inner membrane and containing enzymes and substrates for the Krebs cycle. |
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| The loss of electrons from a substance involved in a redox reaction. |
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Definition
| The addition of electrons to a substance involved in a redox reaction. |
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| A chemical reaction involving the transfer of one or more electrons from one reactant to another; also called oxidation-reduction reaction. |
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| Nicotinamide adenine dinucleotide, a coenzyme present in all cells that helps enzymes transfer electrons during the redox reactions of metabolism. |
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| The splitting of glucose into pyruvate. Glycolysis is the one metabolic pathway that occurs in all living cells, serving as the starting point for fermentation or aerobic respiration. |
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Definition
| A chemical cycle involving eight steps that completes the metabolic breakdown of glucose molecules to carbon dioxide; occurs within the mitochondrion; the second major stage in cellular respiration. |
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Definition
| A sequence of electron carrier molecules (membrane proteins) that shuttle electrons during the redox reactions that release energy used to make ATP. |
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Term
| substrate-level phosphorylation |
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Definition
| The formation of ATP by directly transferring a phosphate group to ADP from an intermediate substrate in catabolism. |
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Definition
| 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. Most ATP synthesis in cells occurs by chemiosmosis. |
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| A cluster of several membrane proteins found in the mitochondrial crista (and bacterial plasma membrane) that function in chemiosmosis with adjacent electron transport chains, using the energy of a hydrogen ion concentration gradient to make ATP. ATP synthases provide a port through which hydrogen ions diffuse into the matrix of a mitrochondrion. |
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Term
| oxidative phosphorylation |
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Definition
| The production of ATP using energy derived from the redox reactions of an electron transport chain. |
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Definition
| An iron-containing protein, a component of electron transport chains in mitochondria and chloroplasts. |
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| A catabolic process that makes a limited amount of ATP from glucose without an electron transport chain and that produces a characteristic end product, such as ethyl alcohol or lactic acid. |
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Definition
| A metabolic sequence that breaks fatty acids down to two-carbon fragments that enter the citric acid cycle as acetyl CoA. |
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Term
| signal transduction pathway |
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Definition
| A mechanism linking a mechanical or chemical stimulus to a specific cellular response. |
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Definition
| A chemical messenger released from the synaptic terminal of a neuron at a chemical synapse that diffuses across the synaptic cleft and binds to and stimulates the postsynaptic cell. |
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| In multicellular organisms, one of many types of circulating chemical signals that are formed in specialized cells, travel in body fluids, and act on specific target cells to change their functioning. |
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Definition
| A molecule that binds specifically to a receptor site of another molecule. |
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| A GTP-binding protein that relays signals from a plasma membrane signal receptor, known as a G-protein-linked receptor, to other signal transduction proteins inside the cell. When such a receptor is activated, it in turn activates the G protein, causing it to bind a molecule of GTP in place of GDP. Hydrolysis of the bound GTP to GDP inactivates the G protein. |
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Definition
| A receptor protein in the plasma membrane that responds to the binding of a signal molecule by catalyzing the transfer of phosphate groups from ATP to tyrosines on the cytoplasmic side of the receptor. The phosphorylated tyrosines activate other signal transduction proteins within the cell. |
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Definition
| An enzyme that transfers phosphate groups from ATP to a protein. |
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Definition
| A small, nonprotein, water-soluble molecule or ion, such as calcium ion or cyclic AMP, that relays a signal to a cell’s interior in response to a signal received by a signal receptor protein. |
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Definition
| A display of the chromosome pairs of a cell arranged by size and shape. |
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Definition
| Chromosome pairs of the same length, centromere position, and staining pattern that possess genes for the same characters at corresponding loci. One homologous chromosome is inherited from the organism’s father, the other from the mother. |
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Definition
| Chromosome pairs of the same length, centromere position, and staining pattern that possess genes for the same characters at corresponding loci. One homologous chromosome is inherited from the organism’s father, the other from the mother. |
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Definition
| A cell containing two sets of chromosomes (2n), one set inherited from each parent. |
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Definition
| A cell containing only one set of chromosomes (n). |
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Definition
| A type of reproduction involving only one parent that produces genetically identical offspring by budding or by the division of a single cell or the entire organism into two or more parts. |
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Definition
| A type of reproduction in which two parents give rise to offspring that have unique combinations of genes inherited from the gametes of the two parents. |
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| A lineage of genetically identical individuals or cells. |
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Definition
| The union of haploid gametes to produce a diploid zygote. |
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| A haploid cell, such as an egg or sperm. Gametes unite during sexual reproduction to produce a diploid zygote. |
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| The diploid product of the union of haploid gametes in conception; a fertilized egg. |
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Definition
| A two-stage type of cell division in sexually reproducing organisms that results in cells with half the chromosome number of the original cell. |
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Definition
| The pairing of replicated homologous chromosomes during prophase I of meiosis. |
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Definition
| A paired set of homologous chromosomes, each composed of two sister chromatids. Tetrads form during prophase I of meiosis. |
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Definition
| The reciprocal exchange of genetic material between nonsister chromatids during prophase I of meiosis. |
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Definition
| (plural, chiasmata) The X-shaped, microscopically visible region representing homologous chromatids that have exchanged genetic material through crossing over during meiosis. |
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Definition
| A diploid cell, in prophase I of meiosis, that can be hormonally triggered to develop into an ovum. |
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Definition
| A haploid cell resulting from meiosis I in oogenesis, which will become an ovum after meiosis II. |
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Definition
| An organism that is heterozygous with respect to a single gene of interest. All the offspring from a cross between parents homozygous for different alleles are monohybrids. For example, parents of genotypes AA and aa produce a monohybrid of genotype Aa. |
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Definition
| An organism that is heterozygous with respect to two genes of interest. All the offspring from a cross between parents doubly homozygous for different alleles are dihybrids. For example, parents of genotypes AABB and aabb produce a dihybrid of genotype AaBb. |
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Definition
| The parent individuals from which offspring are derived in studies of inheritance; P stands for parental. |
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Definition
| The first filial, or hybrid, offspring in a series of genetic crosses. |
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Definition
| Offspring resulting from interbreeding of the hybrid F1 generation. |
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Definition
| An allele that is fully expressed in the phenotype of a heterozygote. |
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Definition
| An allele whose phenotypic effect is not observed in a heterozygote. |
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Definition
| Alternative versions of a gene that produce distinguishable phenotypic effects. |
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Definition
| (plural, loci) A specific place along the length of a chromosome where a given gene is located. |
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Definition
| Having two identical alleles for a given gene. |
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Definition
| Having two different alleles for a given gene. |
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Definition
| The physical and physiological traits of an organism, that are determined by its genetic makeup. |
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Definition
| The genetic makeup, or set of alleles, of an organism. |
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Definition
| Breeding of an organism of unknown genotype with a homozygous recessive individual to determine the unknown genotype. The ratio of phenotypes in the offspring determines the unknown genotype. |
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Definition
| Genes located close enough together on a chromosome to be usually inherited together. |
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Definition
| A chromosome created when crossing over combines the DNA from two parents into a single chromosome. |
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Definition
| A chromosome that is not directly involved in determining sex, as opposed to a sex chromosome. |
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Definition
| A gene located on a sex chromosome. |
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Definition
| A threadlike, gene-carrying structure found in the nucleus. Each chromosome consists of one very long DNA molecule and associated proteins. See chromatin. |
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Definition
| The complex of DNA and proteins that makes up a eukaryotic chromosome. When the cell is not dividing, chromatin exists as a mass of very long, thin fibers that are not visible with a light microscope. |
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Definition
| Replicated forms of a chromosome joined together by the centromere and eventually separated during mitosis or meiosis II. |
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Definition
| A process of nuclear division in eukaryotic cells conventionally divided into five stages: prophase, prometaphase, metaphase, anaphase, and telophase. Mitosis conserves chromosome number by equally allocating replicated chromosomes to each of the daughter nuclei. |
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Definition
| The division of the cytoplasm to form two separate daughter cells immediately after mitosis. |
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Definition
| An ordered sequence of events in the life of a eukaryotic cell, from its origin in the division of a parent cell until its own division into two; composed of the M, G1, S, and G2 phases. |
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Term
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Definition
| The period in the cell cycle when the cell is not dividing. During interphase, cellular metabolic activity is high, chromosomes and organelles are duplicated, and cell size may increase. Interphase accounts for 90% of the cell cycle. |
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Definition
| The synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated. |
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Term
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Definition
| The first growth phase of the cell cycle, consisting of the portion of interphase before DNA synthesis begins. |
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Definition
| The second growth phase of the cell cycle, consisting of the portion of interphase after DNA synthesis occurs. |
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Definition
| The first stage of mitosis, in which the chromatin is condensing and the mitotic spindle begins to form, but the nucleolus and nucleus are still intact. |
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Definition
| The second stage of mitosis, in which discrete chromosomes consisting of identical sister chromatids appear, the nuclear envelope fragments, and the spindle microtubules attach to the kinetochores of the chromosomes. |
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Term
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Definition
| The third stage of mitosis, in which the spindle is complete and the chromosomes, attached to microtubules at their kinetochores, are all aligned at the metaphase plate. |
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Definition
| The fourth stage of mitosis, in which the chromatids of each chromosome have separated and the daughter chromosomes are moving to the poles of the cell. |
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Definition
| The fifth and final stage of mitosis, in which daughter nuclei are forming and cytokinesis has typically begun. |
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Definition
| The centralized region joining two sister chromatids. |
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Definition
| A specialized region on the centromere that links each sister chromatid to the mitotic spindle. |
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Definition
| An imaginary plane during metaphase in which the centromeres of all the duplicated chromosomes are located midway between the two poles. |
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Definition
| The first sign of cleavage in an animal cell; a shallow groove in the cell surface near the old metaphase plate. |
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Definition
| A double membrane across the midline of a dividing plant cell, between which the new cell wall forms during cytokinesis. |
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Definition
| A regulatory protein whose concentration fluctuates cyclically |
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Definition
| A protein that must be present in the extracellular environment (culture medium or animal body) for the growth and normal development of certain types of cells; a local regulator that acts on nearby cells to stimulate cell proliferation and differentiation. |
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