Bio 12 Flashcards
Fredrick Griffith
The first scientist to discover transformation, he was originally looking to create a vaccine for pneumonia
Oswald Avery
Fredrick griffiths student who first discovered that DNA was responsible for the transformation
What were the strains of bacteria that griffith discovered and what did the look like?
The smooth(s) strand caused pneumonia to occur because the mouse couldn’t penetrate the smooth coating
The rough (r) strand didn’t cause pneumonia because the bacteria
What did Griffith do to the smooth bacteria that caused them to not cause pneumonia
He heat killed them, and it worked!
-this showed that the bacteria wasn’t a poison, it needed to be alive to attack the cells
What did Griffith do to the rough bacteria to make them cause pneumonia
He mixes them with the neat killed smooth bacteria. The mice die from pneumonia and in their lungs are the SMOOTH bacteria
Through all of Griffiths experiments, what does he find?
Genetic material from heat killed bacteria and the rough bacteria combined causing a smooth pneumonia causing bacteria- THIS WAS CALLED TRANSFORMATION
What was Avery’s research
Avery continued Griffiths research, he used enzymes to show that when DNA was destroyed, the pneumonia never happened
Alfred Hershey and Marta Chase
They experimented with bacteriophages and using radioactive markers determined that DNA was transferred from bacteriophages to cells.
Which scientist’s expiriments showed that DNA (not protein) holds genetic material?
Avery, and Hershey and Chase
What is the structure of DNA and what is it made of?
-double helix
- 5 carbon sugar, phosphate group, one of four nitrogen bases
What are the 4 nitrogen bases in DNA?
How do they change in RNA?
DNA: RNA:
Adenine - Adenine
Guanine- Guanine
Cytosine- Cytosine
Thymine- URACIL
What are the base pairing rules and who determined them?
In a DNA molecule the amount of Adenine = Thymine, and Guanine = Thymine, they are always paired together with hydrogen bonds.
ERWIN CHARGAFF
How many hydrogen bonds are between Adenine and Thymine?
How many for Guanine and Cytosine?
Adenine& Thymine- 2 hydrogen bonds
Guanine and Cytosine- 3 hydrogen bonds
What class are Adenine and Guanine?
What class are Thymine and Cytosine?
Adenine& Guanine- Purine- Double rings
Thymine & Cytosine- Pyrimidine- One ring
What is transformation?
When (in Griffiths experiments) one bacteria’s DNA transformed into another’s
nucleotide
Monomer of DNA-
- 5-carbon sugar
- phosphate group
- 1 of 4 nitrogen bases
Wilkins and Franklin
Two researchers who worked for years determining DNA’s structure
Watson and Crick
Two ‘researchers’ who stole and published (and got all of the fame for) Wilkins and Franklin’s research.
How much DNA is in a single cell?
How can it be stored?
Around 100,000 times the length of the cell or about 6 feet.
It is wound tightly around histone proteins and itself
What are the layers of how DNA is wrapped?
-wound around histone proteins- nucleosomes
-compacted tightly- chromatin
- wound even more (sometimes)- chromosomes