Block 1 Flashcards
Conducted an expeiment that identified a “transforming factor” which turned avirulent bacteria into virulent
Fredrick Griffith
What type of bond is formed between nuceotides during polymerization of DNA by DNA polymerase?
Phosphodiester
DNA-B
DNA helicase
Opens helix (breaks H bonds) and binds primase to form primosome protein complex
DNA polymerase I
Removes the RNA Primer and replaces it with DNA, fills in the gap (only in prokaryotes!)
How many chromosomes are in a standard human egg?
23X
Synthesis of RNA in bacterial cells
RNA Polymerase
Promoter region of bacterial genes, transcription
Pribnow box
Which RNA molecules is involved in the formation of the spliceosome which is used in eukaryotic RNA processing?
Small Nuclear RNA
Non-coding nucleotide sequences
Intron
Which protein/enzyme is responsible for adding the poly-A tail to the pre-mRNA in eukaryotic cells?
Poly-A-polymerase
What is the name of the enzyme which edits the apo-B mRNA so that a premature stop codon is produced?
Cytidine deaminase
Which proteins/factors binds the GU-rich element beyond the cleavage site?
Cleavage stimulating factor F (CstF)
Stop Codons
UAA, UAG, UGA
Start Codon
AUG
DNA Primase
synthesizes RNA primer once on the leading strand and continuously on the lagging strand, this provides DNA polymerase III with a free 3’ -OH group
Clamp proteins
Loads DNA polymerase III onto single-stranded DNA template, offloads DNA polymerase once it encounters double-stranded DNA. Tightly holds DNA polymerase onto the template for synthesis
DNA polymerase III
synthesizes DNA strand (both leading and lagging) using a template and free 3’ -OH group
- Synthesis of DNA 5’–>3’
- Proofreading 3’–>5’
DNA ligase
Joins Okazaki fragments on the lagging strand together by creating a phosphodiester bond
Topoisomerase
DNA and breaks a phosphodiester bond, cuts to remove supercoils and untangles DNA strands
Telomerase (eukaryotes only)
extends the 3’ end of the parent strand so that gaps on the ends of the daughter strand can be filled in
- synthesizes DNA using an RNA template covalently bound to the protein
- eukaryotic chromosome gets shorter
DNA-A
Initiator proteins
Binds to origin of replication and breaks hydrogen bonds between bases
DNA-C
Helicase inhibitor
delivers helicase to DNA template
Single stranded binding protein (ssb)
binds to single stranded DNA in the replication bubble and prevents it from re-annealing or forming secondary structure
DNA polymerase II
Involved in repairing damaged DNA
-Exonuclease activity (proofreading) 3’–>5’
RNAseH and FEN-1
remove the RNA primer in eukaryotes
leading strand
replicates toward the fork
lagging strand
replicates away from the fork
tRNA
brings AA to the ribosomes during translation
U1 and U2 snRNP bind to
5’ splice junction and branch point
U4/U6 snRNP and 5 snRNP binds to
U1 and U2 to form a loop
U4….
dissociates forming the active spliceosome
The enzymes and proteins that are responsible for mRNA modification are initially bound to?
RNA polymerase II
What describes the linkage between the 7-methyl guanine cap and the first nucleotide of a eukaryote mRNA?
5’-5’ triphosphate bridge
What binds to AAUAA?
CPSF
What bind to the GU rich portion?
CstF
What type of editing does cytidine deaminase do?
Converts C to U
apo-B is edited by?
Cytidine deaminase
How does RNA polymerase II read its substrate during transcription?
It reads the antisense strand in the 3’ to 5’ direction
RNA polymerase I
synthesis of rRNA
RNA polymerase II
synthesis of mRNA and some snRNAs
RNA polymerase III
synthesis of tRNA and some snRNAs
Which RNA encodes the AA sequence of a polypeptide?
mRNA
Prokaryote Promotor
Pribnow box
What ends bacterial transcription?
hairpin loop
In prokaryotes, polymerase is combined with…
Sigma factor
What does Rho do?
in prokaryotes during extrinsic termination of transcription, rho protein causes RNA polymerase to dissociate from DNA
How many origins of replication are found in the genome of E. coli?
one
What is required to first open a region of DNA at the ORI during DNA replication?
initiator proteins
Without telomerase what will happen to eukaryotic chromosomes every time they’re replicated?
they will get shorter
Which direction is DNA read by DNA polymerase?
3’–>5’
How does telomerase work?
In eukaryotes only, it extends the 3’ end using an RNA template
During DNA replication, what prevents re-annealling?
Single stranded binding proteins
The nucleosome is made up of?
two molecules of H2A, H2B, H3 and H4
Which scientists used bacteriophage as a tool to determine that DNA carries hereditary information?
Hershey and Chase
What best describes the nucleosome core?
it is an octamer
A-DNA
it is only found in the dehydrated state
Avery, MacLeod & McCarty
DNA is the transforming factor
Kills protein
Protease
RNase
kills RNA
DNase
lives
Histone core composition?
Octamer: H2A, H3, H2B, H4; 2 molecules of each
