Chapter 13 Flashcards
Ribosomal RNA
RNA molecule that is a structural component of the ribosome
messenger RNA
carries the coding instructions for polypeptide chains from DNA to a ribosome; after attaching to the robosome, mRNA specifies the sequence of amino acids in a polypeptide chain and provides a template for joining amino acids
pre-messenger RNA
the immediate products of transcription in eukaryotic cells
transfer RNA
serves as the link between the coding sequence of nucleotides in the mRNA and the amino acid sequence of a polypeptide chain
template strand
the nucleotide strand used for transcription
nontemplate strand
the other strand of RNA that is not transcribed
transcription unit
a stretch of DNA that encodes an RNA molecule and the sequences necessary for transcription
promoter
a DNA sequence that the transcription apparatus recognizes and binds to; indicates which strand is leading and indicates the direction; determines the transcription start site
RNA coding region
a sequence of DNA nucleotides that is copied into an RNA molecule
terminator
a sequence of nucleotides that signals where transcription is to end, usually part of the RNA coding sequence
ribonucleoside triphosphates
rNTPs a substrate of RNA synthesis; consists of ribose, a nitrogenous base, and three phosphates linked to the 5’ carbon atom of the ribose; during transcription, 2 of the phosphates are cleaved, producing an RNA nucleotide
RNA polymerase
carries out all the required steps of transcription
RNA polymerase I
transcribes RNA
RNA polymerase II
transcribes pre-mRNA and other types of RNA
consensus sequences
the sequences that possess considerable similarity; usually implies that the nucleotide sequence is associated with an important function
general transcription factors
a protein that binds to eukaryotic promoters near the start site and is a part of the basal transcription apparatus
basal transcription apparatus
a complex of transcription factors, RNA polymerase, and other proteins that assemble on the promoter and are capable of initiating minimal levels of transcription
mediator complex
a complex of proteins that is one of the components of the basal transcription apparatus
chromatin-remodeling proteins
binds to a DNA sequence and disrupts chromatin structure, causing DNA to become more accessible to RNA polymerase and other proteins
TATA box
a common consensus sequence: TATAAA commonly found in eukaryotic RNA polymerase II promoters; usually located from 25-30 bp upstream of the transcription start site; determines the startpoint of transcription
TATA-binding protein (TBP)
a polypeptide chain found in several different transcription factors that recognizes and binds to sequences in eukaryotic promoters
