Replication Flashcards
Type of bonds polymerases synthesize
Phosphodiester bonds
Enzyme that removes mismatched deoxynucleotides
3’-5’ exonuclease
During replication, a new nucleotide is added to which group of the previous nucleotide?
3’ hydroxyl group
Is a primer needed for DNA replication?
Yes
Is a primer needed for RNA replication?
No
Enzyme that synthesizes RNA primer
Primase
Polymerase that begins DNA synthesis in the 5’-3’ direction
DNA Polymerase III
Removes RNA primers
RNAase H
Role of DNA polymerase I in prokaryotes
Removes primer and synthesizes new DNA
Role of DNA ligase
Seals nicks between Okazaki fragments
Role of helicase
Unwinds DNA
Another name for DNA gyrase and it’s role
DNA topoisomerase II. It inserts negative supercoils to prevent DNA from being overwound
Types of eukaryotic DNA polymerases
DNA polymerase alpha, beta, gamma, delta, epsilon
Role of DNA polymerase alpha
Synthesizes RNA primer and initiates DNA synthesis of the lagging strand
Role of DNA polymerase beta
Repairs DNA
Role of DNA polymerase gamma
Replicates mitochondrial DNA
Role of DNA polymerase delta
Synthesizes leading strand. Filling gaps after removal of primer
Role of DNA polymerase epsilon
Repairs DNA
Eukaryotic DNA polymerases that have exonuclease activity
DNA polymerase gamma, delta, epsilon
Why do telemeres get shorter after each replication?
DNA polymerase cannot complete synthesis of the 5’ end of each strand
Role of telomerase
Telomerase has a short RNA template complementary to the DNA sequence and possess reverse transcriptase so that it can replace the ends of telomeres.
Direction of the exonuclease activity in RNAse H
3’-5’ exonuclease activity
Types of DNA damage
Thymine dimers, mismatched base and cytosine deamination
Type of DNA damage caused by UV radiation
Thymine dimers
Type of DNA damage caused by DNA replication errors
Mismatched bases
Type of DNA damage caused by Spontaneity or heat
Cytosine deamination
Cytosine deamination results in to conversion of cytosine to which amino acid?
Cytosine is deaminated to form uracil
In cytosin deamination, uracil is identified and removed by?
Uracil glycosylase enzyme
Direction of movement of Dynein
retrograde to microtubule (towards negative (nucleus))
Direction of movement of Kinesin
Anterograde to microtubule (towards positive (periphery))
Which polymerase adds nucleotides and has 3’ to 5’ exonuclease activity
DNA Polymerase III.
Function of DNA Polymerase I
Degrades RNA primer and replaces it with DNA
What is the sequence of nucleotides that telomerase adds
TTAGGG