Transcription Basics
What enzyme synthesizes mRNA?
RNA polymerase II
Where does translation occur in eukaryotes?
ribosomes
How many nucleotides make a codon?
3
Which stage of information flow is disrupted by a mutation preventing RNA polymerase from binding to the promoter, and what is the downstream effect on the cell?
What DNA sequence signals start of transcription?
Promoter
What molecule carries amino acids?
tRNA
How many amino acids exist?
20
What happens immediately after transcription in eukaryotes?
mRNA processing
Which strand is almost identical to mRNA?
coding/nontemplate strand
What codon signals start of translation?
AUG
What does a stop codon do?
signals termination of translation
What does it mean that transcription and translation are coupled in prokaryotes?
they happen at the same time in the same location
Where does transcription occur in eukaryotes?
nucleus
Which site holds the tRNA carrying the growing chain?
P site
What does it mean that the genetic code is “redundant”?
more than one codon can code for the same amino acid
What happens if there is a mutation in the promoter sequence?
transcription cannot start properly
What is the function of transcription factors?
help RNA polymerase bind to the promoter
What happens at the A site?
codon recognition & tRNA binding
Which amino acid always starts a polypeptide chain?
methionine
What if a stop codon appears too early?
a nonfunctional protein is formed