Exam 1- Lecture 3 Flashcards
In prokaryotes, genes are generally
contiguous and tightly packed
IN eukaryotes, genes have
long segments of noncoding DNA
What is the main function of RNA polymerase
unwinds DNA strand
building RNA strand complementary to template DNA strand
Steps of prokaryotic RNA polymerase
RNA polymerase binds to DNA
Double helix separates, polymerization begins
Sigma subunit releases
core polymerase continues elongation
termination occurs
What is the function of transcription factors
initiates TFIIA-H binding
What do RNA pol 1 and 3 transcribe
rRNA and tRNA for ribosome
What does RNA pol 2 transcribe
mRNA coding proteins
What is the most common RNA pol 2 promoter element
TATA box
Where do RNA pol 2 and general transcription factors assemble
promoter
What do insulator binding proteins do
make loops of DNA
ensure correct enhancers with correct genes
blocks action of enhancers not within looped region
Do histone modifications increase or decrease transcription
Increase
What does cytosine methylation do
silences genes
What does the binding of noncoding RNA, antisense RNA, and small interfering RNA to DNA do
causes methylation
What are the six potential control points for eukaryotic gene expression
Transcription control, RNA processing control, RNA transport and localization control, translation control, mRNA degradation control, protein activity control
What happens during translation
mRNA travels to ribosome where proteins are made using amino acids
What do all proteins start with
Met
Why wont 3’–>5’ replication work
the good leaving group (2 extra phosphates) wont be close to the 5’ phosphate on the existing strand
What is the main function of DNA pol 1 and 2
DNA repair
What is the main function of DNA pol 3
replication
What is a klenow fragment
E coli Pol I minus the 5’–>3’ exonuclease domain
What is the function of primase (DnaG)
synthesize short RNA primers using ribonucleotides
What does DNA polymerase need to make new strands
RNA primer
Where does primase mainly work
on the lagging strand because of the okazaki fragments
What is molecule joins the Okazaki fragments
DNA ligase
