Exam 1 Flashcards
Fred Sanger
how nucleotides came together
Walter Gilbert and Paul Burg
basic sequencing of genes
Woese’s 3 domains of life
archaea, bacteria, eukarya
-based on 16s and rRna sequence
Eubacteria
cyanobacteria, actinomycetes, Caulobacter spp, Myxococcus
cyanobacteria
-blue green algae
-filamentous
-created oxygen env
actinomycetes
-terrestrial bacteria
-form hyphae and stalks
-antibiotics
Caulobacter spp
-sticky sessile bacteria or
-mobile free swimming flagellated bacteria
Myxococcus
functions like slime mold by producing fruiting bodies
what forces help stabilize protiens?
hydrogen and ionic bondings
what are 3 main traits of archaea?
extremophiles (osmolarity), high temp, high pressure
Robert Hooke
-first compound microscope
-firs to describe cells
Francesco Redi
showed maggots didn’t spontaneously appear on decaying meat
-only when meat was exposed
Lazzaro Spallanzani
-sealed flask of sterilized meat didn’t produce microbes
-disproved spontaneous generation of microbes
-but results were not valid because experiment didn’t have air
Louis Pasteur
-boiled broth and placed in swan necked flasks
-flasks allowed air in, but not microbes
-proposed that the transmission of microbes cause disease
Edward Jenner
-father of immunology (diseases not form karma)
-smallpox vaccine
-Variolation
-patient: James Phipps (given cowpox, protected from small pox)
-noted for saving millions of lives (attenuation of smallpox and given to people)
John Tyndall
-discovered that organic matter can contain heat-resistant spores
-no spontaneous generation
Joseph LIster
-antiseptic surgery
-phenol was used to sterilize surgical equipment
Ignaz Semmelweis
-hand washing in hospitals
Heat vs chemical fixation for specimen preparation
heat: preserves morphology but not internal structures
chemical: chemical penetrates cell to preserve internal structure
what are 2 common features of dyes?
1) chromophore group- chemical groups with conjugated bonds (gives dyes its color)
2) able to bind to cells
Gram + and - stain used
+ crystal violet, Gram’s iodine
- safarin counter stain
Gram + examples
Bacillus, Streptococcus, Staphyloccus
Gram - examples
Escherichia coli, Pseudomonas aeroginosa
why is electron microscope better?
smaller wavelengths –> better resolution
Germ theory of disease
Robert Kich proposed 4 criteria that must be met to determine if a microbe causes disease
1) microbe always present in diseased organim
2) microbe is isolated from disease organism and grows in pure culture (get disease back)
3) microbe isolated must cause disease in healthy organism
4) re-isolate same microbe from now-sick individual
Barry Marshall 1984
Helicobacter pylori causes stomach ulcers
Prokaryotes vs eukaryotes
- size and simplicity
- most prokaryotes lack internal membrane systems and they are divided into bacteria and archaea
what are fimbrae/ pili functions?
attachment to surfaces, bacterial conjugation and transformation, twitching and gliding motility
what are the functions of the plasma membrane?
encompass cytoplasm
selectively permeable barrier
interacts with external environment (receptors for env. cues, transport systems, metabolic processes)
peripheral proteins
- loosely connected to membrane
- easily removed
- hydrophilic amino acids
integral proteins
- amphipathic (embedded within membrane)
- may exist as microdomains
hopanoids
-a type of bacterial lipid
-found in petroleum
-equivalent to cholesterol in eukaryotes (provide rigidity)
cell wall
- peptidoglycan (polymer = murein)
- rigid structure that lies outside cell membrane
- defines bacteria structure
- 2 types based on Gram stain
- maintains structure/ shape of bacterium
- helps protect cell from osmotic lysis and toxi materials
- may contribute to pathogenecity (attachment)
penicillin
-antibiotic that blocks peptidoglycan synthesis (prevents cell wall formation and cause bacteria to burst)
-inhibits transpeptadaze –> blocks cross-linking
peptidoglycan structure
- NAM and NAG alternating sugars
- alternating D and L amino acids
- strands have helical shape
- chains are crosslinked by peptides for strength (interbridges, peptidoglycan sacs)
why do variations in peptidoglycan structure exist?
want to disrupt other bacteria’s cross links to gain their environment
LPS importance
-contributes to - charge on cell surface (protective barrier because many things trying to attach are +)
-helps stabilize outer membrane
-creates permeability barrier
-attachment to surfaces and biofilm formation
exoenzymes
-enzymes secreted by gram + bacteria
-outside the cell
-get energy from substrates (bonds built with energy)
-dont use ATP because ATP inside cell
-aid in degradation of large nutrients
LAL Assay
-endotoxic assay granules w clotting factor (coagulogen)
-horseshoe crabs w blue blood (hemocyanin assay substituted need for drugs w endotoxins)
-for endotoxin testing
porin proteins
form channels through which small molecules can pass (600-700 daltons ~7 a.a.)
hypotonic vs hypertonic environments
hypotonic: [solute] larger inside cell and cell swells w water; cell wall protects from lysis
hypertonic: [solute] larger OUTSIDE cell and plasmolysis occurs as cell shrinks
lysozyme
- breaks bond bw NAM and NAG
- degrades bacterial cell wall
- made by phage
what happens if cell is in a hypotonic solution and treated with lysozyme or penicllin?
cell will because cell wall destroyed
glycocalyx
- made of: glycoprotein/ glycosaccharide
- capsules and slime layers
- S layers
- aid in attachment to solid surfaces