Chapter 17 Flashcards
Transcription
The synthesis of RNA under the direction of DNA
mRNA
Carries a genetic message from the DNA to the protein synthesizing machinery of the cell
Translation
The synthesis of a polypeptide, occurs under the direction of mRNA
Ribosomes
Site of translation, complex particles that facilitate the orderly linking of amino acids into polypeptide chains
Primary transcript
The initial RNA transcript from any gene, including those coding for RNA that is mot translated into a protein
Triplet code
Flow of info from gene to protein
Template strand
Provides a pattern/template for the sequence of nucleotides in an RNA transcript
Codons
mRNA base triplets
Reading frame
Reading the symbols in the correct groupings
RNA polymerase
Pries the two strands of DNA apart and joins RNA nucleotides as they base pair along the DNA template
Promoter
Where RNA polymerase attaches and initiates transcription
Terminator
The sequence that signals the end of transcription in bacteria
Transcription unit
The stretch of DNA that is transcribed into an RNA molecule
Transcription factors
A collection of proteins in eukaryotes that mediate the binding of RNA polymerase and the initiation of transcription
Transcription initiation complex
The whole complex of transcription factors and RNA polymerase II bound to the promoter
TATA box
Promoter DNA sequence that forms the initiation complex at a eukaryotic promoter
Gene expression
The process by which DNA directs the synthesis of proteins (or in some cases RNA)
RNA processing
Enzymes in eukaryotic nucleus modify pre-mRNA in specific ways before the genetic messages are dispatched to the cytoplasm
Poly-A tail
At the 3’ end of mRNA, an enzyme adds 50 to 250 more adenine nucleotides
RNA splicing
In the eukaryotic nucleus is the removal or large portions of the RNA molecule that is initially synthesized (cut and paste job)
Introns
Noncoding segments of nucleic acid that lie between coding regions
Exons
Coding regions that are expressed, usually by being translated into amino acid sequences
Spliceosome
Several different snRNPs joining together with additional proteins to form an even larger assembly
Ribozymes
RNA molecules that function as enzymes
Alternative RNA splicing
Genes that are know to give rise to two or more different polypeptides, depending on which segments are treated as exons during RNA processing
