Structure of DNA Flashcards
What is Chargaff’s Rule?
There is a ratio of 1:1 for purine to pyrimidine bases in DNA.
Griffith’s experiments demonstrate the principle of _______.
Explain what this means.
“Transformation”
Rough nonvirulent (Type R) => Mouse Lives
Smooth virulent (Type S) => Mouse Dies
Genetic information from the heat-killed S cells was transferred to the R cells, transforming them into virulence.
Explain the significance of Hershey and Chase’s experiments in 1952.
Radioactive phosphorus and sulfur were used to label DNA and proteins in separate viral particles, respectively. The radioactivity was used to visualize the movement of particles as the viruses infected the bacterium.
The nucleic acids were labeled as they entered the bacterial cell, showing that DNA is the hereditary material.
Explain the significance of the experiments conducted by Avery, MacLeod, and McCarty in 1944.
They isolated components from heat-killed S cells and added purified molecules to living R type cells and looked for transformation in the molecules.
Only DNA had the ability to transform when it was isolated.
Explain the following Key Terms:
Transformation Bacteriophage Nucleotide Nitrogenous Base Deoxyribose Sugar Base-pair (bp) Covalent Bond Hydrogen Bond Phosphodiester Bond Sugar-phosphate Backbone Chargaff's Rules Purines and Pyrimidines Adenine, Thymine, Guanine, Cytosine Antiparallel Alignment
