Ch.17 Gene to Protein Flashcards
what is the form of DNA content?
specific sequences of nucleotides
link between genotype and phenotype?
proteins
gene expresssion
process by which DNA directs protein synthesis, including transcription and translation
central dogma
DNA—>RNA—->Protein
template strand
template for ordering the sequence of nucleotides in an RNA transcript
codons
mRNA base triplets, read in 5’ to 3’ direction
what does each codon specify
an amino acid to be placed along a polypeptide
how many codons are there
64
how many triplets are “stop” signals?
three
genes can be transcribed or translated even after
being transplanted from one species to another
what does RNA polymerase attach to?
the promoter
promoter?
region of DNA, upstream, where relevant proteins bind to initiate transcription of that gene
transcription unit
DNA that is transcribed
three stages of transcription
initiation, elongation, termination
transcription initiation complex
transcription factors, RNA polymerase II, promoter
TATA box
promoter crucial in forming initiation complex in eukaryotes
how effective is RNA polymerase (#?)
untwists 10-20 bases at a time, 40/sec in eukaryotes
when does polymerase stop in bacteria?
end of the terminator
when does polymerase stop in eukaryotes?
polymerase continues transcription after pre-mRNA is cleaved from growing RNA chain; eventually falls off
what does 5’ end recieve
modified nucleotide 5’ cap
what does 3’ end recieve
poly-A tail
functions of modifications:
1) facilitate the export of mRNA
2) protect mRNA from hydrolytic enzymes
3) help ribosomes attach to 5’end
introns
stretched of nucleotides that lie between coding regions
codons
exons
