January 14: Cuba Libre!

Here is a link to the article on hereditary alcohol intolerance mentioned in class.

January 14 notes:
January 14, 2009
1. The molecule of heredity: the chemical that transmits information from generation to generation
a. Protein is made of 20 amino acids. Since organisms are complicated and proteins are very complicated it stands to reason that proteins are the molecule of heredity.
b. The Griffith experiment: see page 4 of the text book. Glossy bacteria kill mice, rough bacteria doesn’t. Mice were injected with: live glossy bacteria, heat-killed glossy bacteria, live rough bacteria, and live rough bacteria with heat-killed glossy bacteria. Live glossy bacteria killed mice, live rough bacteria did not kill mice, heat-killed glossy bacteria did not kill mice, and the live rough bacteria with heat-killed glossy bacteria did kill mice. Bacteria cultured from treatment 4 was mostly glossy bacteria. Disproved protein hypothesis.
- Nucleic acids: 4 different nucleotides- Adenine, Thymine, Cytosine, Guanine
c. The Avery/McLeod experiment: (Figures on page 5 of textbook) A culture of glossy cells is heat killed. The dead glossy cells (containing DNA w/ a little protein and RNA)are put in a culture of rough cells. Both rough and glossy cells grew. Therefore, protein hypothesis is disproved. Glossy cells were then treated with Protease or RNase, the glossy cells were put in a culture of rough cells, and both rough and glossy cells grew. This means that RNA and proteins are not the molecule of heredity. Finally, glossy cells were treated with DNase. Then added to a culture of rough cells. Only rough cells grew. This suggests that DNA is the molecule of heredity.
d. The Hershey-Chase experiment: Nonradioactive E. coli cells were infected with phage labeled with radioactive phosphorus and radioactive sulfur. Radioactive P was used for DNA and radioactive S was used for proteins. Part of phage remaining attached to cells was removed in a kitchen blinder. The phages from with the radioactive P were radioactive, but the phages from the radioactive S were not.
2. The structure of DNA
a. Double stranded
i. Backbone: sugar and phosphate links nucleotides in chain
ii. Anti-parallel strands: one runs from 5’ to 3’, the other runs from 3’ to 5’
b. Complimentary base pairing: A and T, C and G; A and T have double bonds, and C and G have triple bonds
3. Genes and proteins
a. What is a gene?
b. What is a mutation - change in DNA sequence of a gene
c. “Inborn error of metabolism” alkaptonuria: caused by mutation to gene in _last_ step of phynylalanine breakdown pathway, recognized by black urine- not harmful to system; phenylketonuria (PKU): mutation to gene in _first_ step of phynylalanine breakdown pathway, which causes a buildup of phynylalanine (can cause mental retardation); aldehyde dehydrogenase deficiency: mutation that does not allow the ethanol to aldehyde break down
~Emily Peterson

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