8.1 Flashcards
(47 cards)
What disease was Griffith researching?
b. Pneumonia
What term did Griffith use to describe the process of one strain of bacteria acquiring a ‘factor’ from another?
a. Transformation
What were the outcomes of Griffith’s experiments with the Smooth Strain and Rough Strain?
Mouse dies for Smooth Strain; Mouse lives for Rough Strain
Why did the Rough Strain become deadly when combined with the Heat Killed Smooth Strain?
The rough strain picked up genetic material/traits of the deadly strain
What components could have been passed from one bacteria type to the other in Griffith’s experiments?
- Proteins
- DNA
- Carbohydrates
- Lipids
Fill in the blank: The combination of Rough Strain and Heat Killed Smooth Strain resulted in the mouse _______.
Mouse dies
True or False: Both the Rough Strain and the Heat Killed Smooth Strain did not kill the infected mouse.
True
Who were the researchers involved in the study of DNA structure and function?
- Frederick Griffith
- Oswald Avery
- Alfred Hershey
- Martha Chase
- James Watson
- Francis Crick
What was the goal of Avery, MacLeod, and McCarty in their experiment?
To determine if protein or DNA was the transforming factor responsible for heredity
They aimed to find the ‘transforming factor’ in Griffith’s experiment.
What happens to transformation when proteins are destroyed with enzymes?
Transformation still occurs
This indicates that proteins are not the transforming factor.
What happens to transformation when RNA is destroyed with enzymes?
Transformation still occurs
This shows that RNA is not essential for transformation.
What happens to transformation when DNA is destroyed with enzymes?
No transformation occurs
This demonstrates that DNA is the key transforming factor.
Which molecule is responsible for transformation?
DNA
Transformation stopped when DNA was destroyed, indicating its critical role.
What was the scientific community’s initial reaction to Avery’s findings?
Scientists were still skeptical that DNA was responsible for heredity
This skepticism persisted despite Avery’s discoveries.
Why did scientists doubt DNA as the cell’s genetic material?
They believed DNA was too simple to account for complex traits
This perception affected the acceptance of DNA’s role in heredity.
In the Hershey-Chase experiment, what was the independent variable?
The element being tagged
This refers to whether the DNA or protein was labeled with radioactive markers.
In the Hershey-Chase experiment, what was the dependent variable?
Whether or not radioactivity was found
This indicated if the labeled component entered the bacteria.
What was the result when bacteria were infected with DNA-marked viruses in Phase 1?
Bacteria contained 32P
This shows that DNA was present in the bacteria after infection.
What was the result when bacteria were infected with protein-marked viruses in Phase 1?
Bacteria contained no markers
This indicates that the protein coat did not enter the bacteria.
What claim can you make about the virus’s genetic material based on the experiment?
Nucleic acids were present inside the cells
This supports the conclusion that DNA is the genetic material of the virus.
What are Chargaff’s Rules?
Rule 1: in any double strand DNA, the amount of guanine equals the amount of cytosine and the amount of adenine equals the amount of thymine.
Rule 2: The relative amount of these bases varies from one species to the next, accounting for genomic diversity.
What does Rule 1 state about the base pairings in DNA?
The number of guanine equals the number of cytosine, and the number of adenine equals the number of thymine.
How does Rule 2 relate to genomic diversity?
The relative amounts of guanine, cytosine, adenine, and thymine vary from one species to the next.
What is the approximate % of G if a species has approximately 31% C?
31%
