DNA Transcription
___ turns cytosine into uracyl.
Deamination
How does RNA polymerase know when it has reached the end of the gene?
It recognizes a termination signal that forms an intrastranded hairpin loops
How does the RNA polymerase know where a gene begins and ends?
It requires promoters
What is the function of the two strands in a promoter?
One has the code and the other is just a place holder
What recognizes AAUAAA?
Poly(a) polymerase
What is responsible for recognizing the promoter? What is it?
Sigma factor; an RNA polymerase subunit
What are operons?
a set of codons in a bacterial cell that work towards a certain goal
What does RNA polymerase II transcribe?
all protein coding genes and some small RNA genes
What are proteins made of?
aminoacids
Genes are turned on or off at different levels in different tissues or cells- how?
by how many copies of the DNA and RNA re made
What do eukaryotes use instead of operons?
coding and non-coding sites
Where does transcription occur in a prokaryotic cell?
in the cytoplasm
Where else does transcription occur in a eukaryotic cell?
in the mitochondria or chloroplast but resembles a prokaryote
Where does transcription occur in a eukaryotic cell?
in the nucleus
What occurs during splicing?
introns are cut out and exons remain
Why would a cell use splicing?
it can get more than one protein per gene depending on which introns are removed
What type of RNA carries information of the DNA that codes for a protein?
mRNA
What is the difference between mRNA in a prokaryote and eukaryote?
mRNA in a prokaryote can immediately be used for translation while in eukaryotes, it must be highly modified in the nucleus before being exported for use
Why do eukaryotic organisms have more evolved polymerases than prokaryotes?
more regulation is needed
What does RNA polymerase I transcribe?
most rRNA genes
What are introns?
parts of the code that aren't needed to make a protein
What is at the 3' end of mRNA?
polyadenylation- AAUAAA
What type of RNA is most abundant in the cell and what does it make up?
rRNA; makes up ribosomes
What does RNA polymerase III transcribe?
tRNA genes, 5S rRNA genes, and some genes for some small structural RNAs
What happens when no lactose is present in a prokaryote?
the lac operon shuts off to save energy
Which strand becomes the template strand?
there is no set rule; it depends on the gene that is being coded
What are promoters and what do they do?
they are special regions of double-stranded DNA in the front of a gene that promotes transcription
What is the function of tRNA?
to convert linear nucleotide information to a protein
What is the function of the lac operon?
to make enzymes that breakdown lactose
