Exam 4: Experiments Flashcards
What is another word for traits?
Phenotypes
What were the two types of streptococcus pneumoniae used in Griffith’s experiment?
Rough strain and smooth strain
What is the rough strain (Griffith’s experiment)?
The bacteria has no capsule
What is the smooth strain (Griffith’s experiment)?
The bacteria has a capsule
Did the living R cells kill the mouse?
No
Did the living S cells kill the mouse?
Yes
Did the heat-killed S cells kill the mouse?
No
Did the mixture of heat-killed S cells and living R cells kill the mouse?
Yes
What was the conclusion from Griffith’s experiment?
There is some form of transferrable genetic material present within the cells
What did Avery, MacLeod, and McCarty try to do that Griffith wasn’t able to do?
Find out what the transferrable genetic material was
What did the first mixture in the Avery-MacLeod-McCarty contain?
Heat-killed S cells
What two things were removed from the first mixture in the Avery-MacLeod-McCarty experiment?
Lipids and carbohydrates
Which three digestive enzymes were added to the initial mixture in the Avery-MacLeod-McCarty experiment?
DNase, RNase, Protease
What does DNase destroy?
DNA
What does RNase destroy?
RNA
What does protease destroy?
Proteins
After the digestive enzymes were added, what was added in the Avery-MacLeod-McCarty experiment?
Living R cells
Which mixture did not develop transformed S cells in the Avery-MacLeod-McCarty experiment?
The mixture with DNase
Why did the mixture with DNase not develop transformed S cells in the Avery-MacLeod-McCarty experiment?
The DNase got rid of all DNA
What was the conclusion of the Avery-MacLeod-McCarty experiment?
DNA was the genetic component that transferred between cells
Did the scientific community accept in the results of the Avery-MacLeod-McCarty experiment?
No, they were reluctant
Which experiment confirmed the results of the Avery-MacLeod-McCarty experiment?
Hershey and Chase’s experiment
What was the test subject in the Hershey-Chase experiment?
Bacteriophage
Which two components of the bacteriophage were labeled in the Hershey-Chase experiment?
Protein and DNA
What were the proteins labeled with in the Hershey-Chase experiment and why?
Radioactive sulfur, because DNA doesn’t have sulfur but proteins to
What was the DNA labeled with in the Hershey-Chase experiment and why?
Radioactive phosphorous, because proteins don’t have phosphorous but DNA does
Which bacteria was used in the Hershey-Chase experiment?
E. coli
After the virus infected the bacterium, how were the virus and bacteria separated in the Hershey-Chase experiment?
Centrifugation
In the Hershey-Chase experiment, the bacterial pellet was found to be radioactive when the bacteria was infected with…
Viruses labeled with radioactive phosphorous (DNA-labeled)
In the Hershey-Chase experiment, the supernatant was found to be radioactive when the bacteria was infected with…
Viruses labeled with radioactive sulfur (Protein-labeled)
The Hershey-Chase experiment confirms that ___ is the genetic material
DNA
What method did Rosalind Franklin use to create images of DNA?
X-ray crystallography
What did Rosalind Franklin’s images of DNA show?
DNA has a double helix structure
Franklin and Wilkins discovered that bases are how far apart?
0.34 nanometers
Franklin and Wilkins discovered that there are how many base pairs per turn, and therefore how long is one helix?
10 base pairs per turm, 3.4 nanometer helix
What was the goal of Watson and Crick’s experiment?
To discover the chemical and structural arrangement of DNA
What were 3 key previous experiments that Watson and Crick used?
- Chargaff’s rules
- Franklin’s C-ray crystallography
- Linus Pauling’s method of working out protein structures using ball-and-stick models
Watson and Crick discovered what 6 components about DNA?
- Double-stranded (antiparallel)
- Helical
- Sugar-phosphate backbone
- Bases on inside
- Stabilized by hydrogen bonds
- Base pairs with specific pairing
What was the goal of the Meselson-Stahl experiment?
Find which hypothesis of how old and new DNA strands interact is correct
What bacteria was used in the Meselson-Stahl experiment?
E. coli
In the Meselson-Stahl experiment, what was generation 0 grown in?
Heavy Nitrogen (15 N)
In the Meselson-Stahl experiment, what was generation 1 grown in?
14 N
In the four DNA samples of generation 2 of the Meselson-Stahl experiment, what was the ratio of 15 N to 15N-14N hybrid to 14 N?
0 to 2 to 2
Which hypothesis did the results of the Meselson-Stahl experiment support?
Semiconservative DNA replication
