Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
35 Cards in this Set
- Front
- Back
|
What are the names of the histone proteins? (5)
|
H1
H2A H2B H3 H4 |
|
|
What is the charge of histone proteins, why is this important?
|
They are positively charged. Most proteins are negatively charged
|
|
|
Which two amino acids carry positive charges?
Why is this significant? |
Arginine and Lysine
Histone proteins are thus made of an abundance of arginine and lysine amino acids |
|
|
what is a nucleosome?
|
DNA donut composed of histone proteins at the core with a DNA "shoelace" surrounding the histone proteins
|
|
|
How many histones are found in a nucleosome and what are these histones?
|
There are 8 total histones in the nucleosome. There are two copies of H2A, H2B, H3, and H4
|
|
|
What happens to DNA missing hte H1 protein?
|
That DNA is sensitive to nucleases
|
|
|
What is the width of DNA without H1?
|
10nm
it is refered to as the "10nm FIBER" |
|
|
What is DNA packaged with proteins known as?
|
chromatin
|
|
|
What is chromatin with a 10nm width known as?
|
euchromatin, also loosely packaged chromatin
|
|
|
What is significant about euchromatin?
|
it is sensitive to nucleases and lacking the H1 histone
|
|
|
What is the role of H1?
|
it condenses the nucleosomes tightly together
|
|
|
What is chromatin with H1 known as?
|
heterochromatin
|
|
|
What is the significance of heterochromatin?
|
it is not sensitive to nucleases
|
|
|
What is the width of heterochromatin?
|
30 nm
|
|
|
Where in the DNA is replication started?
|
Specific sequence known as the origin of replication
|
|
|
What is the initial produce of DNA replication in a eukaryote?
|
Sister chromatids
|
|
|
Where are the sister chromatids connected?
|
centromere
|
|
|
What is required for DNA polymerase to start DNA replication?
|
RNA primer
|
|
|
When a mismatch of a base is made during the DNA replication, what is needed to correct this problem?
|
3' Exonuclease
|
|
|
What molecule actually performs the 3'exoclease?
|
3' exonuclease is a property of all DNA polymerases
|
|
|
What is used to make an RNA strand and how is this different from the replicatoin of DNA?
|
RNA polymerase is needed and this is different from the DNA replicatoin because RNA polymerase does not need an RNA primer
|
|
|
Compare the proofreading of DNA vs. RNA?
|
DNA replication is a HIGH-FIDELITY process and thus mismatched bases are corrected, while RNA synthesis is a LOW FIDELITY process and thus mismatched bases are not corrected
|
|
|
What molecule recognized the origin of replication in bacteria?
|
DNA A protein
|
|
|
What molecule denatures the DNA to expose the bases for replication in bacteria?
|
helicase
|
|
|
In bacteria, what inhibits the single strands from recombining after they have been separated by helicase?
|
SSB
Single strand binding proteins |
|
|
What are the two functions of SSBs?
|
To inhibit the parent strand from reannealing and the protect the single strand DNA from nuclease enzymes
|
|
|
After the strands have been separated and stabilized, what happens before DNA replication can take place and what molecule causes this?
|
PRIMASE (RNA polymerase) must first add the RNA primer the the DNA polymerase to continue from
|
|
|
What is the DNA polymerase, in bacteria, that does most of the DNA replication
|
DNA polymerase 3
|
|
|
What is the name of the fragments of DNA synethesized on the lagging strand?
|
Okazaki Fragments
|
|
|
In bacteria, after the DNA has been reeplicated, what are the final modification made to the newly synthesized strand?
|
DNA polymerase 1's 5' Exonuclease activity will remove the RNA primers and, because it is a DNA polymerase it will replace the RNA with DNA.
After the RNA has been replaced with DNA the DNA segments must be connected. This is done by DNA ligase |
|
|
What are the differences between replication in prokaryotic vs. eukaryotic cells
|
Prokaryotes:
DNA A protein recognizes origin of replication. Eukaryotes: unknown recognition of origin of replication Synthesis of DNA - Prokaryotes: DNA polymerase III does both the leading and lagging strand Eukaryotes: Leading strand - DNA polymerase delta Lagging strand - DNA polymerase alpha Removal of RNA primers: Prokaryote - DNA polymerase I (5'exonuclease) Eukaryote - Unknown Replacement of RNA with DNA: Prokaryote - DNA polymerase I Eukaryote - Unknown Synthesis of telomeres: Prokaryotes - Not necessary because there are no telemeres Eukaryotes - Telomerase |
|
|
What enzyme removes the positive supercoils ahead of advanceing replication forks?
|
DNA topoisomerase II
|
|
|
What is the difference between DNA ligase in prokaryotes and eukaryotes?
|
In prokaryotes, DNA ligase requires NAD. In eukaryotes, DNA ligase requires ATP.
|
|
|
In prokaryotes, what is DNA topoisomerase II often known as?
|
DNA gyrase
|
|
|
What antibiotics inhibit DNA gyrase?
|
quinolones and fluoroquinolones
|
