Lecture 14/15 Flashcards
1
Q
Describe Griffith’s experiment.
A
- Took the pneumonia (virulent) bacteria and injected it into a mouse, this mouse then died
- Then he took the non virulent pneumonia bacteria and injected it into another mouse, this mouse lived
- Then he boiled the virulent bacteria, injected it into a mouse and the mouse lived
- Then he took the nonvirulent and mixed it with the boiled virulent bacteria, injected it into a mouse, and the mouse died
- Concluded that there must be transforming material that can transform bacteria
2
Q
Describe the Avery-Macleod-McCart experiment.
A
- Used the heat killed bacteria and filtered it
- Then they separated the bacteria and treated it with different enzymes that destroy RNA or DNA
- The RNase treated sample and the Protease treated samples both produced the virulent and nonvirulent bacteria
- The DNase only produced the non-virulent bacteria
- Concluded that DNA is the transforming substance
3
Q
Describe the Hershey Chase experiment.
A
- Used isotopic labels as a tracker to track the protein vs DNA
- Sulfur label tracked protein capsid in bacteriophage
- No sulfur was detected in cell after the bacteriophage infected it
- Sulfur was detected in bacteriophages
- Phosphorus label tracked DNA core in bacteriophage
- After infection, phosphorus was found in the cells
- No phosphorus was found bacteriophages
4
Q
What are the purines?
A
adenine and guanine
5
Q
What are the pyrimidines?
A
cytosine and thymine/uracil
6
Q
What is the complementary base pairs?
A
A to T and C to G
7
Q
How many base pairs are in a helix?
A
10 bp per turn
8
Q
What is a euchromatin?
A
where most transcription takes place
9
Q
What is a heterochromatin?
A
a highly condensed DNA
10
Q
What are the 3 levels of DNA packing?
A
1) nucleosomes
2) nucleosomes fold to form 30nm of chromatin fibre
3) fold again to form 300nm loops
