Gene Expression: From Gene to Protein

Gene Expresion
Click the card to flip 👆
1 / 46
Terms in this set (46)
Gene Expresion
The process by which DNA directs the synthesis of proteins
Transcription
is the synthesis of RNA using information in the DNA
messenger RNA (mRNA)
carries the genetic message from the DNA to the protein-synthesizing machinery of the cell
Translation
is the synthesis of a polypeptide using the information in the mRNA
ribosomes
complex particles that facilitate the orderly linking of amino acids into polypeptides. site of translation
primary transcript
initial RNA transcript from any gene
triplet code
genetic instruction for a polypeptide written in the DNA as a series non overlapping, three-nucleiotide words
template strand
provides pattern or template for the sequence of nucleotides in an RNA transcript
reading frame
sequence of symbols under consideration
codons
mRNA nucleotide triplets
RNA polymerasepries the two strand of DNA apart and joins together RNA nucleotides complementary to the DNA templatepromotorthe DNA sequence where the RNA polymerase attaches and initiates transcriptionterminationthe sequence that signals the end of transcription in bacteriatranscription unitthe stretch of DNA that is transcribed into an RNA moleculestart pointthe nucleotide where RNA synthesis actually beginstranscription factorproteins that mediate the binding of RNA polymerase and the initiation of transcriptiontranscription initiation complexthe whole complex of transcription factors and RNA polymerase II bound to the promotorRNA processingboth ends of the primary transcript are altered5' capa modified form of guanine nucleotide added onto the 5' end after the first 20-40 nuclotidespoly-A tailAt the 3' end, an enzyme adds the 50-250 more adenine nucleotidesRNA splicingstage of RNA processing in the eukaryotic nucleus is the removal of large portions of the RNA moleculeIntronsthe noncoding segments of the nucleic acid that lie between coding regionsExonsother regions that are eventually expressed usually by being translated into amino acid sequencesalternative RNA splicingwhen two or more polypeptides, depending on which segment are treated as exon during RNA processingspliceosomethe removal of introns is accomplished by a large complex made of proteins and small RNA calledribozymesRNA molecules that function as enzymestransfer RNA (tRNA)the message is a series of codons along an mRNA moleculeanticodonthe particular nucleotide triplet that base-pairs a specific mRNA codonaminoacyl-tRNA sythetasescarries out the correct matching up of tRNA and amino acidwobbleflexible base pairing at a codonP siteholds the tRNA carrying the growing polypeptide chainA siteholds the tRNA carrying the next amino acid to be added to the chainE siteDischarged tRNA leave the ribosomeribosomal RNAsRNA of ribosome, ribosomal subunitsignal peptidetargets a protein to the ERsignal-recogintion particleprotein RNA complex that recognizes a single peptidemutationsthey are responsible for a huge diversity of genes found among organisms because mutations are the ultimate source of new genespoint mutationschange in a single nucleotide pair of genenucleotide-pair substitutionthe replacement of one nucleotide and its partner with another pair of nucleotidessilent mutationsa mutation with no observable effectmissense mutationchange in one animo acid to anothernonsense mutationit causes translation to be terminated prematurely making a shorter polypeptideinsertionaddition of nucleotide in a genedeletionloss of a nucleotide in a geneframeshiftwill occur whenever the number of nucleotides inserted or deleted is not a multiple of threemutagensa number of physical and chemical agents that interact with DNA in ways that cause mutations