Biology Unit 8 study guide, DNA replication, Scientists (s/r-strain) and (Rosalind Franklin + other scientists)

Who was Fredrick Griffith?

Scientist from 1928 who wanted to learn more about pneumonia and the flu

Fredrick Griffiths time-line/year of EXP

1928

Fredrick Griffiths experiment

R-strain - injected into mouse = living mouse

S-strain - injected into mouse = dead mouse

Boiled S-strain + living R-strain = dead mouse

Fredrick Griffiths conclusion

Something in the dead S-strain was transferred into the living R-strain when mixed together that killed the mouse

Who was Oswald Avery?

Scientist form 1944 who wanted to learn more about Griffiths EXP and “transforming vairable”

Oswald Avery’s time-line/year of EXP

1944

Oswald Avery’s experiment

Boiled S-strain + living R-strain + Carboxylase = dead mouse

Boiled S-strain + living R-strain + Protease = dead mouse

Boiled S-strain + living R-strain + Lipase = dead mouse

Boiled S-strain + living R-strain + RNAse = dead mouse

Boiled S-strain + living R-strain + DNAse = living mouse

Oswald Avery’s conclusion

DNA is the transforming variable, but did not know how DNA was the transforming variable

Who were Hershey and Chase?

Scientists from the 1952 who wanted to prove that DNA was the genetic material

Hershey and Chase time-line/year of EXP

1952

Hershey and Chase experiment

Radioactive PRO → Allow bacteria to infect cell = cell is not radioactive, then, radioactive sulfur (35s) → Centrifuge to separate → Radioactive supernatant (pellet at the bottom of flask) = PRO is not the genetic material

Radioactive DNA → Allow bacteria to infect cell = cell is radioactive, then, radioactive phosphorus (32p) → Centrifuge to separate → Radioactive pellet (pellet at top of flask, supernatant at the bottom) = DNA is the genetic material

Bacteria used in Hershey and Chase’s EXP

T2 Bacteriophage

Hershey and Chase conclusion

DNA is the genetic material

Sulfur is found in what

PRO

Phosphorus is found in what

DNA

What does a virus (bacteriophage) look like when drawn

Full name of DNA

Deoxyribonucleic acid

Nucleotide

Monomers for nucleic acid

How many strands does DNA have

2, it is double stranded

How many strands does RNA have?

One

Strands of DNA are not parallel, they are __________.

Antiparallel

Why is DNA antiparallel?

Because the strands would look like this:

3’ ——————- 5’

5’ ——————- 3’

Phosphate group chemical formula

Deoxyribose chemical formula (CHO)

What type of process is DNA replication?

Semi-conservative

What is the top strand called?

Leading strand

What is the bottom strand called?

lagging strand

What’s Helicase?

An enzyme that unwinds DNA and breaks the hydrogen bonds.

What is topoisomerase?

ENZ that Goes at the top of DNA and makes sure that the DNA does not overwind

What does SSB stand for?

Single stranded binding protein

What does DNA polymerase do?

Finds a primer, builds a new molecule(I and III), and it also checks for errors(III)

What are Okazaki fragments?

Pieces made on the lagging strand

Which way does the DNA polymerase work to create the new DNA

3’ → 5’

What does lygase do?

Glues the okazaki fragments together

Where does DNA replication occur?

Nucleus (sometimes)

When does DNA replication occur?

During interphase (s-phase)

Helicase

Unzips the strand

Primase

Adds RNA primers

lygase

gluer of Okazaki fragments

Where does DNA Polymerase I work?

On bottom/lagging strand

Where does DNA polymerase III work?

Top/leading strand

Where does DNA polymerase work on specifically? *hint: what does it replace

Where there are RNA primers and replaces them with correct nucleotides

Order of enzymes in DNA replication

Helicase - Flattens out DNA + breaks H+ bonds

SSB - Placed to make sure DNA would not attach again

Topoisomerase - Placed at top of DNA to prevent overcoiling

Primase - Places RNA primers

DNA polymerase:

III - Works on building leading strand

I- replaces RNA primers w/ right nucleotides, and builds lagging strand

Ligase - Glues together Okazaki fragments

DNA polymerase III - checks for errors and fixes them

DNA polymerase I vs III

III - adds new DNA strand and checks for errors in the end

I - replaces RNA primers and replaces with correct nucleotides

Who actually discovered that DNA was double stranded?

Rosalind Franklin

Who took credit for discovering that DNA was double stranded?

Watson and Crick

Who were the men who made Rosalind Franklin feel low to their superiorness, and later stole her work?

Watson and Crick

What impact did Wilkins have to Rosalind Franklin?

Wilkins hired her, but was also really mean and discriminatory to her for being a woman

Some studies and experiments of Rosalind Franklin?

X-ray crystallography studies on DNA (finding that DNA is made up of 2 strands)

Working on figuring out the complex structure of a virus

More too!

What was Rosalind Franklins photo of DNA called?

Photo 51