Term | Definition |
nucleotide | an organic molecule that consists of a sugar, a phosphate, and a nitrogenous base; the basic buliding block of a nucleic -acid chain. |
double helix | modle that compares the structure of a DNA molecule, in which two strands wind around one another, to that of a twisted ladder |
complimentary base pairing rules | the rules stating that in DNA cytosine paris with guanine and adenone pairs with thymine and that in RNA cytosine pairs with guanine and adenine pairs with uracil |
replication | the process by which DNA is copied |
DNA polymerase | an enzyme that catalyzes the formation of the DNA molecule |
central dogma | theory that states that, in cells, information only flows from DNA to RNA to proteins |
RNA | ribonucleic acid, a natural polymer that is present in all living cells and that plays a role in protein synthesis |
transcription | the process of forming a nucleic acid by using another molecule as a template; particularly the process of synthesizing RNA by using one strand of a DNA molecule as a template |
RNA ploymerase | an ezyme that starts (catalyzes) the formation of RNA by using a strand of DNA molecule as a template |
mRNA | messenger RNA; form of RNA that carries genetic informaiton from the nucleus to the cytoplasm, where it serves as a template for protein synthesis |
rRNA | ribosomal RNA; form of RNA tha tis in the ribosome and guides the translation of mRNA into a protein; also used as a molecular clock |
tRNA | transfer RNA; form of RNA that brings amino acids to ribosomes during protein synthesis |
translation | the portion of protein synthesis that takes place at ribosomes and that uses the codons in mRNA molecules to specifiy the sequence of amino acids in polypeptide chains |
condon | in DNA and mRNA, a three-nucleotide sequence that encodes an amino acid or signifies a start or stop signal |
anticodon | a region of a tRNA molecule that consists of a sequence of three bases that is complementary to an mRNA codon |
mutation | a change in the structure or amount of the genetic material of an organism |
point mutation | a muation in which only one nucleotide or nitrogenous base in a gene is changed |
frameshift mutation | a mutation, such as the insertion or deletion of a nucleotide sequence, that results in the misreading of the code during translation because of a change in the reading frame |
mutagen | agent that can induce or increase the frequency of mutation in organims |
DNA fingerprint | a pattern of DNA characteristics that is unique, or nearly so, to an individual organism |
protein | an organic compound that is made of one or more chains of amino acids and that is a principal component of cells |
amino acid | a compound of a class of simple organic compounds that contain a carboxyl group and an amino group that combine to form proteins |
chemical reaction | process by which substances change into different substances through the breaking and forming of chemical bonds |
reactant | a substance or molecule that participates in a chemical reaction |
product | a substance that forms in a chemical reaction |
activation energy | the minimum amount of energy required to start a chemical reaction |
catalyst | substance that decreases the activation energy and increases the reaction rate in a chemical reaction |
enzyme | a molecule, either protein or RNA, that acts as a catalyst in biochemical reactions |
substrate | a part, substance, or element that lies beneath and supports another part, substance, or element; the reactant in reactions catalyzed by enzymes |
monomer | molecular subunit of a polymer |
polymer | large molecule that is formed by more than five monomers, or small units |