DNA Flashcards
How does the Hershey Chase experiment demonstrate that DNA is the building block of Genetic Information and Not proteins
2 part experiment where radioactive proteins coated ( But not radioactive DNA )viruses were allowed to infect bacteria.
These viruses put their DNA inside the bacteria but the new DNA wasn’t radioactive.
2nd part allowed radioactive DNA viruses but not with a radioactive protein coat to infect the bacteria.
The radioactive DNA was passed on to the bacteria.
Purine bases for DNA
Adenine & Guanine
Pyrimide bases for DNA
Thymine & Cytosine
Which nucleotide contains a double ring?
Purine base: Adenine & Guanine
All nucleotides contain:
Phosphate, 5-Carbon Sugar, Nitrogen- Containing base
Chargaffs rules: (2)
The amount of A, T, C, G varies in species to species
In each species the amount of A = T & C =G
What does antiparallel mean in the description of DNA
The sugar-phosphate groups that are chained together make each strand are oriented in opposite directions.
Where is the phosphate located?
5’ posistion of the sugar
What type of bond occurs in the nitrogen bases of DNA
Hydrogen Bonds
The process of DNA replication that results in 2 double helix molecules, each having one parental and one new strand
Semiconservative replication
Three main events in DNA replication:
Unwinding of DNA molecule, complementary base pairing, joining of new DNA strands
Separates double-stranded DNA into single strands
DNA helicase
Binds to single-stranded DNA and prevents it from reforming a double helix
Single-Stranded binding protiens (SSB)
Synthesizes short RNA primers
DNA primase
Synthesizes DNA in the leading and lagging strands, RNA Primers, Filling the gaps with more DNA, and proofread newly made DNA
DNA polymerase
Covalently attaches adjacent Okazaki fragments in the lagging strand
DNA ligase
Where specifically does DNA replication start at
Origin of replication site
List steps and enzymes used to replicate DNA
- DNA helicase unzips the double helix
- Single stranded binding proteins (SSB) attach to separated DNA strands preventing them from reforming.
- DNA primase places short primers on the strand to be Replicated
- DNA polymerase synthesizes new DNA forming complementary base pairs ( proofreading too )
Then
Converts the RNA sequences to DNA
- DNA ligase glues the Okazaki fragments together
Which strand are the Okazaki fragments found on?
The lagging strand
How does chemotherapy drugs stop cancer
They mimic one of the nucleotides used in DNA creation.
When a cancer uses these base pairs, replication stops and the cell dies.
Area of active replication is called:
The replication fork
Enzyme used to make sure areas outside of the replication fork do not super coil
DNA gyrase
Explain why replication must occur differently on the leading strand vs the lagging strand
Replication can only take place on the 5’ - 3’ direction.
Replication of the lagging stand must work backwards in the 5’ - 3’ direction
Compare DNA replication in prokaryotes and eukaryotes
Prokaryotic begins at a single origin places and works in both directions towards the termination region
Eukaryotic DNA replication begins at multiple orgins of replication and continues until the replication forks meet