Genetics OUTLINE UNIT TWO

Biology 120: Genetics

Topical Outline

Unit Two

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V.
Linkage
A.
Determination of independence (eg., Chi Square Testing)
B.
Frequency of Recombination as an estimate of distance
C.
Two Point Crosses
D.
Three Point Crosses
1.
Determination of gene order
2.
Calculation of map distances
E.
Linkage Map Units are not strictly additive, nor does one linkage map unit strictly correspond to any fixed distance.


VI.
Molecular Genetics
A.
DNA as the Hereditary Material
1.
Griffith and transformation
2.
Avery, MacLeod and McCarty and transformation
3.
Hershey and Chase and the Waring Blender experiment
B.
DNA Structure
1.
Watson and Crick
2.
Nucleotides (Deoxyribose, Nitrogenous Base, Phosphate)
3.
Nitrogenous bases (Adenine, Thymine, Guanine, Cytosine)
4.
Complementary Base Pairing: The Secret to Life
5.
Secondary Structure: The Double Helix
6.
RNA structure vs. DNA structure
1.
RNA contains the sugar ribose, instead of deoxyribose.
b.
The bases in RNA are adenine, guanine, cytosine and uracil (no thymine). Uracil behaves just like thymine in base pairing.
c.
RNA is single stranded, not double stranded. As the helical secondary formation of DNA is the consequence of base pairing, RNA is not helical. NOTE: Some RNA sequences do quite a bit of internal base pairing between different sections of the same RNA molecule. In those regions, the molecule will assume the typical, double stranded helical secondary structure.
d.
RNA is typically much shorter than DNA.
C.
DNA Replication: DNA's Autocatalytic function
1.
Semi-conservative replication.
a.
Meselson and Stahl experiments with heavy nitrogen
b.
Two sides separate and construct new partner strands, selecting nucleotides by complementary base pairing.
2.
Enzymology
D.
Protein Synthesis: DNA's heterocatalytic function
1.
DNA is an information archive; the active agent in protein synthesis is RNA.
2.
Protein Synthesis has two stages
a.
Transcription (RNA Synthesis)
b.
Translation (Protein construction)
3.
Protein Synthesis involves three kinds of RNA
a.
messenger RNA, transcribed from structural genes
b.
ribosomal RNA, transcribed from ribosomal DNA
c.
transfer RNA, transcribed from transfer DNA
4.
The genetic code is triplet, degenerate, and universal.

Material for Exam II ends here

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