Chapter 7- Transcription Flashcards
What is transcription?
RNA synthesis from DNA
What is translation?
protein synthesis from RNA
Which is more reactive Ribose or Deoxyribose?
Ribose because of the OH2 molecule attached to it
What is a ribozyme
an enzyme made of only RNA, responsible for peptide bond synthesis
What is peptide bond synthesis
the linking of amino acids
What makes Ribozyme?
non coding DNA
What is ribozyme made of?
RNA, not proteins
What type of RNA is translated into proteins?
mRNA
Where are ribosomes located in the cell?
Can be found at the endoplasmic reticulum in eukaryotes
What are ribosomes responsible for?
protein synthesis
What is transfer RNA responisble for?
serve as adaptors between mRNA and amino acids during protein synthesis
Which strand is the coding strand?
the NON- Template strand
What is the difference between the coding strand and the RNA transcript?
all T’s are converted to U’s (they are equivalent)
How is an RNA strand read
5’ ——> 3’
What is the relationship between the template strand and the RNA transcript?
They are complementary
What is the Promoter Region?
serves as recognition site so sigma factor knows which DNA strand to bind to (upstream of txn start site)
What does RNA polymerase do?
It unwinds the DNA helix and adds ribonucleotides, synthesizing the RNA in the 5’ —> 3’ direction
Does RNA polymerase require a primer?
nah
What is the Sigma Factor?
part of the RNA polymerase and recognizes and binds to the DNA strand
Where is the txn start site?
+1
Where does RNA polymerase stop
at the terminator sequences
Where upstream are promoter sites for prokaryotic transcription?
-35 and -10
In eukaryotic cells, which RNA polymerase is responsible for coding?
RNA Polymerase 2
How many types of RNA Polymerase do Eukaryotic cells have compared to bacteria?
Eukaryotic cells have 3 types which prokaryotic cells have 1 type
WHere does eukaryotic transcription occur?
in the nucleus
WHat is RNA Polymerase 3 responisble for?
tRNA
What is the TATA box?
It is the promoter sequence at -25
What does TBP do?
It binds the TATA-box and bends DNA
What does TFIIH do?
It unwinds strands and phosphorylates RNA tail. (Uses ATP for energy)
How are Eukaryotic RNAs processed?
Pre- mRNA’s are processed by capping, polyadenylation, and splicing
How is bacterial RNA processed?
Trick question, its not
Characteristics of prokaryotic txn
no processing
sigma factor
TATA box at -35 and -10
Characteristics of Eukaryotic txn
has processing
TBP
TATA box at -25
What does splicing get rid of?
Introns
What are introns?
non-amino acid/ nucleotide coding regions
What does trimer bind?
U4, U5, U6
What is Branch point A?
U2
Why is it called a TATA box?
It is composed of a series of A’s and T’s
What is a Holo-enzyme?
It is an RNA Polymerase with a sigma factor attached
WHat is the -10 sequence?
TATAAT
What is the -35 sequence?
TTGACAT
