Modern Genetics Flashcards
1900
De Vries and Correns rediscovered Medelian genetics (botanists)
1902
Morgan’s experiments supported chromosomal theory of Inheritance (fruitflies)
1902 continued
Garrod hypothesized herritable factors determine inborn errors of human metabolism (Alkaptonuria)
1905
Bateson championed Mendelism and coined “genetics”
1909
Johannsen coined “gene”
1930s
Beadle and Tatum promoted one gene one enzyme hypothesis
Mutation
Change in sequence nucleic acids in DNA
Theory
Not testable, broad explanation, many lines of evidence
Beadle and Tatum experiment
hypothesized that mutation altered a gene coding for an enzyme treated type of mold with x-rays, determine wild mold could live on minimal nutrients media
Macromolecule/polymer
carbohydrate, protein, nucleic acid
Building block/monomer
sugars, amino acids, nucleotides
Srb and Horowitz
(Stanford) experiment with mold mutants with enzymes gets zapped
Pauling et al
revised one gene-one enzyme to one gene one protein, to one gene one polypeptide
Crick
central dogma genes code for polypeptide, DNA strand template-> transcription-> mRNA-> translation-> protein
Codon
set of three consecutive nitrogenous bases on DNA or RNA
4 n-bases
4^3 to make 20
Polypeptide recipe
nucleotide sequence in nuclear DNA dictates order by ribosomes bond amino acids, DNA-> ribosome thru nuclear envelope
Transcription
process of transferring info from DNA to RNA, 3 stages, initial, elongated, termination
Translation
process of trafering info from RNA to protein
tRNA molecules
maintain specificity of the relation among codons and amino acids, cytoplasm contains lots of amino acids and tRNA
Mutations
affect transcription, translation or expression,
Types of Mutation
silent (codon doesn’t change but polypeptide does)
missense (changes polypeptide)
nonsense (stop)
frameshift (extra nucleotide) (1 pair deletion) (3 cell deletion)
Sickle cell
go crazy
