Part B: Lecture 8 Flashcards
Why do scientist use model organisms?
They ate used to understand biological processes
Examples of unicellular model organisms
E-coli bacteria
S. cerevisiae yeast
Neurospora crassa - orange bread mold
unicellular model organisms can be grown in ____ and _____
-agar plate (colonies)
-liquid media (cells)
You can grow unicellular organisms in two types of media
-minimal media (MM)
-complete media (CM)
Minimal media (MM) contain three things:
-carbon source (ex. glucose)
-energy source (ex. glucose)
-salts (ex. Na+)
Complete media (CM) contain four things:
-amino acids
-sugars
-lipids
-nucleotides
Source of prototroph?
wild
Source of auxotroph?
lab
Genotype of prototroph?
genes are all functional (+)
Genotype of auxotroph?
one gene is non-functional
Phenotype of prototroph?
can grow on CM and MM
Phenotype of auxotroph?
can grow on CM
Significance of Srb and Horowitz experiment
experimental proof of the one-gene-one-enzyme + invention of biochemical pathway analysis
Srb and Horowitz experiment summary
1.WT cells exposed to UV light (1 mutation/cell)
2. Collected cells with random DNA damage
3. Collected mutant strains that can’t make arginine
4.Grew mutant cells on CM, MM, MM + Arg etc.
5. WT cells can make Arg in specific pathway using 3 enzymes made by 3 genes
Mutant strains (def.)
cells with random DNA damage
Mutagen (def.)
something capable of inducing changes in DNA
By studying mutant types, you can learn _____
how wildtype works
Purpose of biochemical pathway analysis
To determine how a cell/organism synthesizes an organic molecule
Mutation in ___ gene prevents production of ___ enzyme and blocks the pathway at ____ place
-one
-one
-one
Biochemical pathway analysis: providing different nutrients- WT appearance
the nutrient has recused the mutant so the nutrient is after the blocked step
Biochemical pathway analysis: providing different nutrients- mutant appearance
the nutrient has not recused the mutant so the nutrient is before the blocked step
Positive controls (def.)
If the experiment worked these will be positive
Negative controls (def.)
If the experiment worked these will be negative
Purpose of transformation rescue
to determine if a new mutation is in a known gene
Transformation (def.)
the uptake and use of DNA or RNA by a cell/organism
Transformation in animals is called ____
transfection
Transformation rescue experiment summary
- Plasmid with functional gene transforms mutant strain
- WT appearance: transgene rescued mutant so transgene=mutant gene
- Mutant appearance: transgene doesn’t rescue mutant so transgene ≠ mutant gene
