BIOL 375 Ex 1

what are properties of all cells

structure, metabolism, growth, evolution

what makes up all of the microflora in someone’s body

microbiome

who built the first microscope and saw euk. cells first and published *Micrographia*

robert hooke (1600s)

who built a microscope and was the first to see bacterial cells

Antoni van Leeuwenhoek 1600s

when was the golden age of microbiology

1800s

who (1660’s) demonstrated that maggots in decaying meat were the offspring of flies

Francesco Redi

who (1760’s) demonstrated that a sealed flask of meat broth sterilized by boiling failed to spoil

Lazzaro Spallanzani

what are properties of some cells

differentiation, communicate (signal transduction), motility, horizontal gene transfer

Questions that started the science of Microbiology (E)

•Question of Spontaneous Generation

–The belief that life generated spontaneously from putrid & decaying materials

•Nature of Infectious Disease

–Why were some diseases contagious?  What caused them?

Disproval of spontaneous generation (E)

•Francesco Redi (1660’s) demonstrated that maggots in decaying meat were the offspring of flies

•Lazzaro Spallanzani (1760’s) demonstrated that a sealed flask of meat broth sterilized by boiling failed to spoil

Pasteur’s swan neck flask

who is the father of modern surgery due to aseptic technique (1800s)

Joseph Lister

what is described by the tendency to automatically reject new information

or knowledge because it contradicts established norms or beliefs.

The Semmelweis Reflex

Koch’s postulates

1\.Microbe must __always__ be:

ØPresent in __diseased__ animals

ØNever in __healthy__ animals

2\.The organism must be isolated in __pure__ culture from the diseased animal

3\.The isolated culture must cause the __same__ disease in a healthy animal

4\.The organism must be:

Ø __re-isolated__ from the experimental animal

Øconfirmed to be the __same__ organism as found in the __original__ animal

Pasteur’s swan-neck flask experiments (E)

liquid was sterilized in the flask, and when upright airflow could happen but no microbes, and when down all could get in, showed that SG isn’t real

What led up to the development of the Germ Theory (E)

•Observations:

–many diseases were contagious

–microbes seen everywhere, spoiled food, and caused fermentation

•Cleaning of wounds by Joseph Lister in the 1860’s

•Ignaz Semmelweis & hand washing, 1847

Contributions of Koch (E) 1800s

•Developed Germ Theory of Disease

–A.k.a. “Koch’s Postulates”

•Developed method for isolating pure cultures of microorganisms

–Pure culture = 1 single species present

•Discovered the causes of anthrax, TB, cholera

•Helped develop the petri plate with Richard Petri

Contributions of Pasteur (E)

•Hypothesized that microbes also cause disease (Germ Theory of Disease)

•Disproved Spontaneous Generation of microorganisms

•First to recognize significance of optical isomers

•Discovered microbial fermentation

•Invented Pasteurization

•Developed rabies vaccines + others

who •(1851-1931)

–Hypothesized presence of 1st virus

–Enrichment culture technique

Martinus Beijerinck

who •(1856-1953)

–Soil bacteria

–Metabolism of various organisms, including *chemolithotrophy* and *chemoautotrophy*

–Bacterial nitrogen fixation

Sergei Winogradsky

which domain is most closely related to humans (E)

archaea, diverged after bacteria

what did Carl Wose do (1990’s)

used rrna to find 3 domains (rrna is well conserved)

what did norman pace do

looked for rrna in funky places, saw that some can live off non-organic stuff, unculturables

Endosymbiont Theory (E)

by lynn margulis

2 pathways

evidence: chloro and mito both have own DNA and ribosomes and rrna (70s instead of 80s) and binary fission all resemble bac

Differences between eukaryotes and prokaryotes (E)

prok: circ dna chrom, cell membrane, cytoplasm, ribosomes, flagella, cell wall

euk: linear, plasma membrane, cytoplasm, ribosomes, endomembrane system makes lipids, flagella or cilia, cell wall

__Heterotrophs__

need more than one carbon source

autotrophs

get carbon from CO2

__Facultative__

grow with or without o2

__Microaerophilic__

grow with only a small amount of O2

strep vs staph

strep= strands

staph= clumped like grapes

spirochete

zig zag guy

vibro

look like a comma

what is the average size of a bacterium

2-4 micrometers

what is the theoretical small limit for life

.15 micrometers

what is the surface area to volume ratio relationship

large SA:V= small cell, small cell has a higher metabolism, faster cellular transport, faster reprod

what are the 4 levels of bacterial classification

1. gram
2. shape/size
3. growth requirements
4. physical components

what is the function of the cytoplasmic membrane

maintains a positive internal turgor pressure, permeability barrier, protein anchor, E conservation, ECT occurs there, detects environmental signals, structure support for pili/flag, secretes virulence factors, communication signals, toxins, wastes, ion transport and energy storage

what are the types of ion transport

simple (driven by proton motive force), ABC (periplasmic binding protein and get E from ATP), group translocation

Group Translocation (E)

chemical modification of cargo through phospho pyruvate

glucose is phosphor as it enters the cell

a phosphate from PEP goes through some enzymes to phosphor substrate

means that glucose-6p is ready to do glycolysis

allows for certain molecules to be picked first for energy use

what is the difference in the name of the cell wall for prok vs archaea

prok- peptidolglycan

arch- pseudopeptidolglycan

what is the function of the cell wall

helps maintain turgor pressure, provides shape and rigidity

General structure of peptidoglycan (E)

made up of NAG and NAM glycan chains that are cross linked by peptide crossbridges that have tetrapeptide side chains extending up

the beta (1,4) bonds is sensitive to lysozyme attack

D-aa help it avoid protease attack

how does the cell wall of mycobacteria and mycoplasmas compare

bac- have waxy coat so doesnt gram stain and isnt sensitive to antibiotics, have to do acid fast stain to see (TB)

plasm- no PDG only cell mem

Differences between gram-negatives and gram-positives (E)

•Gram-Positives have a *thick* cell wall, up to 40 layers of PDG

–Often surrounded by S-layers, capsules, or slime layers

\-has teichoic acid (extend partially) and lipoteichoic acid (extend through), no periplasm, no porins, stains purple

•Gram-Negatives have a *thin* cell wall with 1-3 layers of PDG

–Surrounded by an outer membrane, often encapsulated, has periplasm, has porins, no teichoic acid, outer membrane has LPS (lipopolysaccharides- •Protection from ,Dehydration, Phagocytes, Immune system. Certain antibiotics (esp. penicillin)) that contains o-specific polysaccharide (antigenic), and lipid A (a toxin), porins extend only in the outer membrane, PDG is surrounded by periplasm, stains pink

what does the periplasm do

–All secreted proteins contained here until transported across outer membrane

–Also contains proteins & enzymes for nutrient processing and building cell wall

what are the external structures of the cellular envelope

capsules and slime layer known as glycocalyx

\-Capsules are thick and tightly bound to the cell

\-Slime layers are thin and loosely bound to the cell

what is the function of the glycocalyx (capsule and slime layer)

•Retention of nutrients & moisture

•Protection

•Attachment

Are often part of biofilms

what are mucoid colonies and biofilms

biofilm- lets bac stick to stuff and gives them a safe place to live, how they colonize, can degrade things, made of poly sacc matrix

mucoid- goopy slime layer

what is made of the pilin subunit

fimbriae- attachment and pellicles (film layer at the top) (shorter and fewer)

pili- attachment (longer and more) twitching motility, and transfer of DNA through conjugation

what is the nucleoid

sing circ prok genome found throughout cell, uses binding proteins to do supercoiling

what is a plasmid

not always present circular DNA separate from genome that doesn’t encode housekeeping genes and often encodes virulence factors, carries antibiotic resistance, and can destroy stuff like oil slicks

what is the prok ribosome

70s (50+30) target for antibiotics, rRNAs and proteins cause change in protein synth

what are cell inclusions/ reserves

for phosphate or sulfate when environ nut is limited

what are magnetosomes

—Inclusions containing iron

—Magnetite, greigite

—Magnetosomes serve to orient the swimming of magnetotactic bacteria within a magnetic field

have monolayer membrane

what are endospores

met resting/ dormant cells keep cell alive in bad conditions and are resistant to dessication, heat, chem, spread thru wind, water, guts (C.diff), and are only found in G+, pathogens make spores

sporulation vs germination

s=makes endospore

g=returns to veg state

what are the orientations to spore formation

reproductive, terminal, subterminal, central

what are 3 types of microbial locomotion

flagella (swimming), gliding (needs contact with a surface, can use fimbriae), gas vesicle (regulate aquatic positions)

what makes up a flagellum and what powers its movement

flagellin monomers, Proton motive force powers rotation (can be Na in marine areas)

what are the 4 flagellar arrangements

polar (monotrichous, or amphitrichous), lophotrichus (branched), peritrichous (all over)

how do endoflagella of spirochetes work

turn it like a corkscrew to burrow found in the periplasm, lots of G-

how to flagella compare in G+ and G-

G- has 4 rings (L,P,MS, and C rings)

G+ has MS and C

L- LPS, P- periplasmic, MS- motor proteins, C- cytoplasmic membrane

mot proteins turn it like a rotor

how does the direction of flagellar movement relate to speed

CCW- propells

CW- flag flares out and causes it to tumble

there are reversible and unidirectional flagella

helps them stay in one general area

what is directed movement

when it encounters a gradient of attractants or repellents and changes flagellar motion to move away for towards an area

what are the types of bacterial taxis

—Chemotaxis (chemicals)

—Phototaxis (light)

—Aerotaxis (oxygen)

—Osmotaxis (high ionic strength)

—Hydrotaxis (water)

—Magnetotaxis (in a magnetic field)

Chemotaxis Capillary Assays (E)

bac sense environment with receptors that note when a concentration of something increases, if attractant, will increase runs over tumbles, w/o gradient they increase their tumbles

more on group level, increases the net movement

methyl accepting chemotaxis proteins (MCPs) detect stimuli and tell bac when to run and tumble, MCPs generally cluster to one end