dna replication d1.1

the 2 main reasons why DNA rep happens

1. growth and repair

2. reproduction

what i semi conervative replication

DNA replication in which each DNA molecule consist one original strand and one new strand

helicase function

• enzyme that breaks hydrofgen bonds between the 2 parent strands

• UNZIPPING THE DNA

DNA polymerase function

• enzyme that add the free-floating nucleotides to the new strand, creates bond between phosphate from of free nucleotide and the sugar of the last nucleotide on the strand

what is PCR, state simply

PCR (POLYMERASE CHAIN REACTION) = amplifies DNA (AKA Increase the DNA size dramatically)

what is primer

short segment of DNA that signals where to start copying

which enzyme is added in PCR? State what is it, and how is alternating heat related to PCR/helps?

• Taq polymerase = heat tolernat DNA polymerase → will be added along with free nucleotides

• alternating heat → can break the hydrogen bonds between the 2 strands → speeds up replication

which process can sepearte DNA

gel electrophoresis seperates DNA BASED ON THEIR LENGTH

how to do electrophoresis?

• put dna fragments into one end of porous gel → put DNA at the negaative side → DNA is negative too, so once the system is turned on → DNA repels the negative end of the porous gel → pushes itself further

which typa DNA fragment can go further awaycloser to the poistive end?

• the smaller the further away

• bigger DNA fregeents get stuck on the negative side

list applicaiotn of polymerase chain reaction and gel electrophoresis, sttae how easily

• testing for COVID19

• swab and isolate the RNA (it have RNA not DNA)

• BUT WE NEED DNA: so we do reverse transcription → transcribe RNA to dna

• after having that DNA → use it to do PCR

brief flowchart of how to do PCR AND ELECTROPHORESIS and do paternity testing

isolate short tandem repeats → cur the tandem repeatas out → PCR to amplify the sample → make a a lot of copies of them → seperate them using gel electrophoresis → differnt banding patterns

leading strand vs lagging strand during replication

leading strand: replication in continuous because the the new strand is replicated from 5’ → 3’ (anti parallel to the 3’→5’) towards the replication fork

lagging strand: nucleotides are added in the 5’→3’ direciton in short segments called okazaki fragments aawy from the replication fork

state and explain function of all enzymes that is included in the DNA replication

1. helicase → unzips DNA

2. dna primase → produces RNA primer which provides initiation point for DNA polymerase 3/it guides the DNA polymerase 3

3. DNA polymerase 3 → adds the free floating nucleotides and creates a new strand in 5’→3’ direction. It moves in opposite directions of the 2 strand cuz they anti parallel

• leading strand: continuously adding, moving into the replcation fork

• lagging strand: adds nucleotides in seperate fragments, moves outward of the replicaiton fork (okazaki fragments)

4. DNA polymerase l → removes the RNA primers from lagging strand, replaces them with DNA nucleotides

5. DNA ligase → joins the okazaki fragments together at the lagging strand, by fomring phosphodiester bonds → sugar phosphate backbone

which enzyme is in charge of proofreading, what it does?

DNA polymerase 3, recognises mismatch and replace the nucleotide will the right one