Bacteria cultured since late 19th cent, Koch's postulates. Important in identification and understanding of disease.
Isolate organism, (through filtration technique and in petri dish with nutrients), culture pathogen, reintroduce in organism, observe whether disease reemerges, re-isolate pathogen, re-culture it, establish causality.
cultured on nutrient agar on petri dish, you can identify strains and species by color and shape.Variablity! Some well defined margins, others not as well defined.
free-living cells, useful for many studies, for cell/molecular biology, many defined strains, produce large numbers of them. Bottom center break off flagella, discard body and study proteins of flagella (pseudomonas). Top center see cilia, complex cells b/c live complex lives.
life too diverse to study all of it; biochemical mechanisms highly conserved across orgs, reduce effort by reducing # of studied orgs, hopefully representative, more similarities than dissimilarities.
model organism: Ecoli
human gut symbiont/pathogen. most commonly used lab cell, tool for molecular biol, important historically b/c used in so many studies..used to grow DNA
Budding yeast: saccharomyces cerevisiae
very small euk and little bigger than bacterium; very thick cell wall like bacterium; small genome; many strains; easily transformed; versatile metabolism; haploid: expression easy to work with b/c immediately apparent; basic cell functions; doesn't have all things seen in euk cell but has many
biflagellate unicellular chlorophyte alga; haploid; normal cell that has all cellular process (not like yeast). easy to grow and moderat. fast gen. time; grow to conc. more than millions/mL, 10-12micron flagella length; grown phototropially, a swimming chloroplast b/c it takes up most of cell #1 for studying photosynthesis/photochem
chlamydomonas induced sexuality/mutants
Induce sexuality by starving it by taking away phosphorus and nitrate..it shrinks and grows flagella and becomes gamete. Mate via pillus and DNA and sheds cell wall, forms diploid zigote. shorter or longer flagella mutations/some beat strangely.
chlamydomonas and "rescue experiment"
Mate mutant gene with wildtype..mutant phenotype is rescued or reverted to wild type and reveals functionality of gene. Look at diagram.
ciliated, easily grown; well est. strains and transformable; b/c of cilia has macro/micro nuclei allow for controlled expression. Has a lot of microtubules, cilia attached to them. cell needs to very rapidly regulate various parts of genomes so it can carry out its normal functionality.
Tetrahymena macro/micro nuclues
micro: full copy of DNA and genes. Macro: portion of genome that's actively being used be cell and amplifies DNA being used. continues to increase that DNa so theres lots of DNa that can be involved in rapid expression in transc. and transl.
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