November 22, 2011
1.) See attached
2.) The organism I am working with is Escherichia coli str. 'clone D i14 and the gene is thrL.
3.) The protein produced from this gene is thr operon leader peptide homoserine kinase. This
Tests that can screen for mutagenesis:
Ames: determination of mutagenic properties.
Used to test any additive for consumption- Red dye #5 in m&ms300lbs/ day will cause mutations.
If you fail this test the product can't be used- FDA, EPA w
Mutations are the driving force for changing proteins and evolution.
In a heterozygous individual, one allele is normal and that protein functions.
The other allele (recessive) is mutated and doesn't function.
Recessive homozygous exhibits a
Types of RNA:
mRNA- messenger- these are the "genes"
tRNA- transfer- transfers AAs to mRNA
rRnA- ribosomal- makes large and small subunits through folding.
snRNA- small nuclear- remains in nucleus for intron removal
Si or microRNA- short int
History of Genetics
Question to be answered: Which cell component allows the next
generation to achieve traits of the first generation?
DNA- synthesis, mutations, repair, handling DNA
RNA- gene regulation, processing
Cell is filled with tRNA, ribosomes (rRNA and protein complexes), mRNA,
enzymes, AA, siRNA
Enzymes are for glycolysis, aerobic respiration, Krebs cycle, electron
AA (Fig 6.2)- some essential Aas must be consumed, others we synthesize
Eukaryotes have 4 repair mechanisms:
Proofreading: 3' to 5' exonuclease activity by the DNA
polymerase (the most effective mechanism)
Base excision repair: repair of damaged bases
Nucleotide excision repair: dimer repair T=T;
Regulation of Gene Expresion
Levels of Control in Eukaryotes (Figure 20.2)
Transcriptional control: determines which DNA is coded into
RNA. Most critical. If we only make needed RNA, we save energy at
all of the levels.
Processing control: don't pol
Only amplifying one small portion of a large genome
The first extension flanks or precedes the exon but extends beyond.
After a couple of cycles, we bookend and produce the desired
Cycle 21: 2,097,192 of the desired fragment. 42 of the longer
Genetics of Cancer
Cancer cells are our own cells and indistinguishable from healthy cells.
Very difficult for our immune system to target without hitting and killing the
healthy cells also.
Cancer cells are unique in their growth rates and inability to a
Gene Mapping- a technique to find relative gene locations on a
Now outmoded by technology
How to determine expressivity:
Determines whether or not transcription of a particular gene is
occurring in a part
In the G1 phase chromosomes have a single chromatid
In the S phase the chromatid gets copied so that a single chromosome has
Mitosis occurs in autosomal cells and maintains the fidelity of the genome.
Meiosis occurs i
Just because mRNA is produced, we don't necessarily get a protein from it.
Do we get a protein?
Preform Protein Isolation
SDS-PAGE (Sodium Dodecyl Sulfate- Poly Acrylamide Gel
Lyses open cells
Meselson and Stahl- Most beautiful experiment in biology
Hypothesis: either DNA replicates via conservative, semi-conservative,
or dispersive replication.
Bacteria were grown in N15 (heavier than N14) until all of the DNA was
Then all N15 was washed