DNA replication (nicely exclusive?) Flashcards
1
Q
What is DNA replication?
A
- DNA copies itself before cell division
- Takes place during interphase of cell cycle
(creates genetically identical sister chromatids
2
Q
Step 1 of DNA replication?
A
- The DNA molecule unwinds.
- So it’s just the DNA untwisting, u can see the base pairs too
3
Q
Step 2 of DNA replication?
A
- The DNA unzips and the polynucleotide strands separate.
(Due to helicase enzyme)
Breaking the hydrogen bonds between the bonds.
(The bases are exposed)
- So basically the DNA is being separated from their pair
- From the helicase enzyme (looks like a helicopter) from below
4
Q
Step 3 of DNA replication?
A
- Free nucleotides are activated and are attracted to the exposed bases.
Free nucleotides align with complementary bases
A-T, C-G
- So they bases are exposed right?
- Now they are kinda just rebuilding themselves to other complementary bases
(btw, we actually have no idea where these complementary bases come from, they just spawn ig)
- In addition, phosphate molecules activate the free nucleotides
5
Q
Step 4 of DNA replication?
A
- DNA polymerase join the nucleotides together.
To form new strands.
Forging covalent phosphodiester bonds
- Basically the end game of the previous step
- Ig state about the polymerase enzyme helping in the joining
6
Q
Step 5 of DNA replication?
A
- 2 new identical DNA molecules are formed
7
Q
Step 6 of DNA replication?
A
- DNA winds up into a double helix
8
Q
Additional info!?!?!
(observe only)
A
- In addition, the DNA polymerase works in a 5’-3’ direction down the new strand, continuous process
- However, DNA = anti-parallel, therefore the enzyme only works in small sections on the other molecule, leaving gaps
- Another enzyme , DNA ligase, joins up the small sections to complete the process
Visuals: a ladder at the bottom connected to 2 incomplete ladders to the top. DNA polymerase connecting n shi but some gaps left soo ligase there to join em up.
