| Term | Definition |
|---|
| genes | a sequence of nucleotides in DNA that perform a specific function such as coding for a particular protein |
| proteins | complex molecules composed of on or more polypeptide chains made of amino acids and folded into specific three-dimensional shapes that determine protein function |
| amino acid | the monomer unit of a polupeptide chain that is composed of a carboxylic acid, an amino group, and a side group that differentiates it from other amino acids |
| transcription | the process in which DNA is used as a template for the production of complementary messenger RNA molecules |
| translation | the process by which a ribosome assemble amino acids in a specific sequence to synthesize a specific polypeptide coded by messenger RNA |
| mRNA | the end product of transcription of a gene, is translated by ribosomes into protein |
| tRNA | a from of RNA that is responsible for delivering amino acids to the ribosomes during the process of translation |
| rRNA | a form of RNA that binds with ribosomal protein to form ribosomes |
| RNA polymerase | enzyme that transcribes DNA into complementary mRNA |
| codon | sequence of three bases in DNA or complementary mRNA that serves as a code for a particular amino acid |
| start codon | specific codon (AUG) that signals to the ribosome that the translation commences at that point |
| stop codon | specific codons that signal the end of translation to a ribosome |
| upstream | region of DNA adjacent to the start of a gene |
| promoter | sequence of DNA that binds RNA polymerase upstream of a gene |
| template strand | the strand of DNA that the RNA polymerase uses as a guide to build complementary mRNA |
| coding strand | the strand of DNA that is not used for transcription and is identical in sequence to mRNA, except it contains uracil instead of thymine |
| terminator sequence | sequence of bases at the end of a gene that signals the RNA polymerase to stop transcribing |
| primary transcript | mRNA that has to be modified before exiting the nucleus in eukaryotic cells |
| 5' cap | 7-methyl guanosine added to the start of an primary transcript to protect it from digestion in the cytoplasm and to bind it to the ribosome as part of the initiation of translation |
| poly-A polymerase | enzyme responsible for adding a string of adenine bases to the end of mRNA to protect it from degradtion later on |
| poly-A tail | a string of 200 to 300 adenine base pairs at the end of AN mRNA transcript |
| exons | segments of DNA that code for part of a specific protein |
| introns | noncoding region of a gene |
| spliceosomes | particles made of RNA and protein that cut intron from mRNA primary transcript and joins together the remaining coding exon regions |
| mRNA transcript | mRNA that has been modified for exit out of the nucleus and into the cytoplasm |
| reading frame | one of three possible phases in which to read the bases of a gene in groups of three |
| anticodon | group of three complementary bases of tRNA that recognizes and pair with a codon on the mRNA |
| aminoacyl-tRNA | a tRNA molecule with its corresponding amino acid attache4d to its acceptor site at the 3' end |
| A site | (acceptor) site in the ribosome where tRNA brings in an amino acid |
| P site | (peptide) site in the ribosome where peptide bonds are formed between adjoining amino acids on a growing polypeptide chain |
| releasing factor | a protein involved in the release of a finished polypeptide chain from the ribosome |
| housekeeping genes | genes that are switched on all the time because they are needed for life functions vital to an organism |
| transcription factors | proteins that switch on genes by binding to DNA and helping the RNA polymerase to bind |
| gene regulation | the turning on or off of specific genes depending on the requirements of an organisms |
| lactose | a disaccharide that consists of the sugars glucose and galactose |
| B-galactosidase | the enzyme reponsible for the breakdown of lactose into its component sugars, glucose and galactose |
| operon | a cluster of genes under the control of one promoter and one operator in prokaryotic cells; acts as a simple regulatory loop |
| operator | regulatory sequencese of DNA to which a repressor protein binds |
| lac operon | a cluster of genes under the control of one promoter and one operator; the genes collectively code for the enzymes and proteins required for a bacterial cell to use lactose as a nutrient |
| lac I protein | a repressor protein that bind to the lac operon operator, preventing RNA polymerase from trancribing the lac operon genes |
| repressor protein | regulatory molecules that bind to an operator site and prevent the transcription of an operon |
| signal molecule | a molecule that activates an activator protein or represses a repressor protein |
| inducer | a molecule that binds to a repressor protein and causes a change in conformation, resulting in the repressor protein falling of the operator |
| trp operon | a cluster of genes in a prokarytoic cell under the control of one promoter and one operator; the genes govern the synthesis of the necesary enzymes required to synthesize the amino acid tryptophan |
| corepressor | a molecule (usually the product of an operon) that binds to a repressor to activate it |
| mutation | change in the genetic material of an organism |
| germ cell mutation | change in the genetic info. contained in the reproductive cells of an organism. It is inheritable. |
| somatic cell mutation | change in genetic info. contained in every cell except the reproductive cells. it is not inheritable |
| point mutation | mutation at a specific base pair in the genome. Can involve substitution, insertion or deletion of base pairs. |
| silent mutation | mutation that does not result in a change in the a.a. coded for & therefore does not cause any phenotypic change. |
| missense mutation | mutation that results in the single substitution of one amino acid in the resulting polypeptide |
| nonsense mutation | mutation that converts a codon for an a.a. into a termination codon |
| frameshift mutation | causes the reading frame of codons to change, usually resulting in different a.a. being incorporated into the polypeptide |
| translocation | transfer of a fragment of DNA from one site in the genome to another location. Usually occur between 2 nonhomologous chromosomes |
| transposons | (jumping genes) short strands of DNA capable of moving from one location to another within a cell's genetic material |
| inversions | reversal of a segment of DNA within a chromosome. |
| mutagen | substance or event that increases the rate of mutation in an organism. (physical or chemical) |
| induced mutations | mutations caused by agents outside of the cell |
Combine with other sets
Share on Facebook
Share on MySpace