DNA Synthesis Flashcards
DNA replication is initiated at specific sites on DNA called…..
Replication origins
What is the length of Bacterial cell cycle?
20-30 minutes
How many replication origins does bacteria have?
Single replication origin on their genome
What are the phases of cell cycle in bacteria?
2 phases
S phase + M phase
What is length of mammalian cell cycle?
16-24 hours
What are phases of mammalian cell cycle?
G1, S, G2, M
G stands to Gap
S stands for synthesis
M stands for mitosis
What is purpose of G1 phase?
It allows cell to prepare for next phase
Allow synthesis of all the extra histones you need for S phase
Synthesis of DNA polymerase
Ensures building blocks for making DNA are present
What is purpose of G2 phase?
Prepare to condense chromosomes + Allow their segregation in mitosis
How many replication origins are present in eukaryotic cells?
There are multiple replication origins
What DNA polymerase are present in bacteria + what are their functions?
DNA Polymerase I = repair
DNA polymerase II = repair
DNA polymerase III = replication
Others= repair
What DNA polymerases are present in eukaryotic cells?
DNA polymerase alpha= replication DNA polymerase beta = repair DNA polymerase gamma= mitochondrion DNA polymerase delta= replication DNA polymerase epsilon = replication
What is purpose of DNA polymerase and what does it require to function?
It synthesises DNA
Acts in 5’-3’ direction
Utilises A-T and C-G base pairing to synthesise new DNA strand
Requires DNA template, DNA/RNA primer, dNTP building blocks and Mg2+ ions
What are dNTPs?
Are building blocks of DNA
There are 4 of them => dATP, dCTP, dGTP, dTTP
What is purpose of DNA helicase?
Separates base pairs producing single strands using ATP
What is purpose of topoisomerase?
Goes in front of helicase + gets rid of cells in DNA