Ch 13-15 Flashcards
Frederick Griffith Bacterial Transformation
put viral & nonviral bac. in mouse, put heat killed in mouse and survived and mixed heat killed with no viral but mouse died, didn’t know what molecule caused the change
Oswald Avery with Griffith’s exp.
Removed ICF from heat killed & destroyed proteins, carbs, lipids but transformation happened
destroyed DNA and transformation didn’t occur so DNA was transforming molecule
Rosalind Franklin & Photo 51
X-ray crystallography to take picture of DNA
Identified helical structure & nucleotide bases
Hershey & Chase
Confirmed DNA was passed on
bc radioactive P was found in infected bacteria but radioactive S in protein coat wasn’t
Messelson Stahl experiment
Spun e-coli in heavy nitrogen (isotope) and normal nitrogen, then combined them and DNA split with one old and one new strand, proved DNA reproduced semi-conservatively
DNA Replication
- Helicase unwinds double helix
- SS bind prot. stabilize separated strand from repairing
- Topoisomerase ahead of replication form relieving strain
DNA Replication
- Primase synthesizes RNA primers from DNA template
- DNAplll synthesizes leading strand in 5-3 towards rep fork
- Primase synthesizes RNA primers on lagging strand
DNA Replication
- DNAplll adds nucleotides to primer on lagging making okasaki
- DNApl replaces primers on strands with nucleotides
- DNA ligase joings okasaziki by joining sugar-phosphate backbones
- DNAp proofread
Protein synthesis
RNAp transcribes DNA and makes a copy (mRNA- only exons that actually code)
mRNA leaves nucleus to ribosome where tRNA brings anticodons to mRNA’s codons
meth starts the process of making a protein and stops once stop codon is reached forming an amino acid seuqnce
Mutations
Changes in genetic material of cell or virus
Mutations of DNA/RNA or protein is inheritable
Gene & Chromosomal mutations
Gene- small scale
Chrom- large scale
Point mutations
change in one nucleotide in DNA strand
ex: sickle cell: mishapen RBC’s causes lethargy, lack of O2, clotting
Substitutions
Replacing nucleotide in DNA strand
can cause silent, missense, and nonsense
Missense
Change in codon for new amino acid forming new protein
cystic fibrosis
Nonsense
Change in codon making stop codon forming segment of protein
duchenne muscular dystrophy
Swapping out bases
Transition mu: purines (A G) or pyrimidines (C T) switch
Transversion mu: purines and pyrimidines switch
Insertions & deletions
Add or remove nucleotide in DNA strand, frameshift mutations
Add shifts sequence right
Remove shifts sequence left
Cri du chat is a deletion mutation of chromsome 5p
Prokaryotic operon
multiple genes working together to express info, regulate genes by controlling transcription
operator is on/off switch
can be switched off by repressor proteins or turned on by activator proteins
Operon with repressor
Active repressor binds to the operator blocking RNAp from transcribing DNA
If repressor is inactive DNA can be transcribed
Operon with activator
Activator with a ligand binds b/w promoter & operator allowing RNAp to transcribe
If no ligand activator is inactive & RNAp can’t bind
Eukaryotic operon
each gene is transcribed into own mRNA & regulated on its own
DNA is transcribed in nucleus
transcription factors help RNAp bind to begin (ex TATA box)
Epigenetics
how behavior & environment change genes
heritable chemical modifications affect gene expression
