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Study of organisms/infectious diseases too small to be seen with the human eye
- 10x more microbes than human cells
coined the term cell
- "micographia" journal
1st to see living microbes and 1st to describe bacteria
- called these organisms animalcules
cells come from cells
- proved it by maggot expirement
father of modern microbiology
- demonstrated air is filled with microorganisms and proved this by using swan necked flask
(bacteria & archaea are prokaryotes)
- binary fission
- no nucleus
- genetic material not contained in membrane bound organelle
-fungi, yeast, protozoa. helmenths
; has nucleus
1. HIV (virus)
2. TB (bacterial organism
3. Malaria (protozoal disease)
-produce oxygen and nitrogen
-resident microbes (flora)
-food production (fermentation)
-bioremediation**= use organisms to degrade environmental waste (clean up oil spills, radioactive waste)
-synthesis of products (ethanol, antibiotics, express proteins-insulin, pesticides)
- gastric ulcers/hep. c
atoms sharing a pair of electrons. these are strongest. polar or non-polar. hard to break.
- non-polar: bonds btw identical atoms or btw atoms that have similar attraction for electrons (same valence number type thing) H-H or C-H
- polar: one atom has a greater attraction to the electrons than the other. produces slight diference within molecule called polarity. one side slightly negative and other side slightly positive. O-H
ex. cations & anions. charged atoms are attracted to each other & form a bond thus each atom gains or loses an electron.
- cathode: attracts cation
- anthode: anion is attracted to this, its positive charged.
ionic bonds are weaker than covalent, & dissociate in h2o.
A type of weak chemical bond formed when the slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule. they hold molecules together & covalent bonds hold atoms together
-ex, water molecules & DNA.
constantly being formed & broken at room temp. primarily in proteins
when an atom becomes slightly polarized, with a weak negative charge @ one end (due to concentration of electrons) and a weak positive charge @ the other (lack of electrons)
substance that consists of a single type of atom
- 99% of all living matter made up of C,N,H,O
+ phosphorous & sulfur
# of protons = # of neutrons (except in isotopes.
- and # of protons = # of electrons (except in ions)
outer orbital contains max. # of electrons (8 usually)
- 2, 8, 8, etc.
- gain, lose, or share with other atoms when trying to become stable. molecules formed when atoms bond together
makes up 70% of all living organisms
-hydrogen bonding of water produces polar molecule
if soluble, must have some type of polarity-called hydrophyllic (ex. water) HAS CHARGE
- if molecule has no charge, it isnt soluble and is hydrophobic
negative log of hydrogen concentration in solution
-0 HIGHLY ACIDIC
-14 HIGHLY ALKALINE (basic)
-when hydrogen and hydroxide ions are equal, solution is neutral
- high hydrogen (H) is ACID
- high hydroxide (OH) is BASE
Large molecules composed of thousands of covalently connected atoms.
- polysaccharides (carbohydrates)
- nucleic acids
Lipids are also macromolecules
- are polymers
- large molecules formed by joining smaller subunits together (this involves dehydration rxn)
- when macromolecules are broken down into smaller subunits, water is added (this is called hydrolysis rxn)
- molecules of communication
- over 50% of cell dry weight
- catalyze rxns, compose & shape structures, gene regulation, nutrient procurement
- composed of numberous combination of 20 amino acids (sub-units)
- protein shape/function depends on shape of the sequence of amino acids
-all have a carboxyl group (COO-), an amino group (NH2+), a central carbon, and a side chain, and hydrogen
- AA's that form proteins are held together by peptide bonds(type of covalent bond formed btw carboxyl group of on AA and the amino group of another AA this rxn causes release of water thus forming peptide bond)
(COO-) and (NH2+)
both have partial negative charge
sequence of amino acids
- determines other protein features
- stabilized by covalent bonds between amino acids
the regular or periodic folding of the primary structure
- alpha helix structure (spiral)
- beta sheet structure (pleated)
this new configuration results from weak bonds formed between amino acids
- 3 dimensional structure with 2 major shapes: globular and fibrous
- globular: looks like intestines
- fibrous: looks like rope
- OVERAL FOLDING OF POLYPEPTIDE. becomes functional protein.
1. carbohydrates (polysaccharides)
3. nucleic acids
-composition and shape of certain bacterial structures
-an amino group (NH2+)
-a carboxyl group (COO-)
-common source of food & energy
-form part of nucleic acids
-form part of bacterial cell wall
-classified by number of carbons in molecule
-most common are 5&6 carbon sugars
-----ex: glucose, galactose, mannose, fructose
Match the following with the appropriate bond:
protein (amino acids)
lactose= glucose & galactose
sucrose = glucose & fructose
maltose = glucose & glucose
-chains of monosaccharides
-imp in plant cell wall
-shorter chains called oligosaccharides
a phosphate group
purine = adenine and guanine
pyrimidine = thymine and cystosine
saturated fats contain no double bond and are solid at room temperature.
unsaturated fats contain double bonds and are liquid at room temperature (oils)
- monounsaturated = 1 double bond
- polyunsaturated= >1 double bond
- simple lipid
- structure consists of 4 membered ring
- insoluble in water
- if one of the rings has an OH group attached its classified as a STEROL
-most important compound lipid
-made up of a phosphate, & two fatty acids attached to a glycerol molecule
- phosphate head is POLAR & SOLUBLE: hydrophillic
- fatty acids are NON-POLAR & INSOLUBLE: hydrophobic
What is the source of light for the following:
bright field microscope
phase contrast microscope
λ = wavelength of light
sinθ = 1.00
η = refractive index of medium
distance = 0.61 wavelengths of light divided by the refractive index x 1.00
distance become larger when the wavelength is larger and the resolution becomes poorer.
thus, as D becomes smaller, wavelength shortens & resolution improves.
-two lenses: objective & ocular.
-4x 10x 40x 100x
- 0.2 um (2x10-7m) maximum resolving power
amplifies difference between refractive indexes of cells and surrounding medium
- translates between light and dark
uses electromagnetic lenses, electrons, and flourescent screen to produce image
-resolution increased 1000 fold over bright field microscope 0.3nm (1x10-10m)
-observes fine detail
-beam of electrons pass through or scatter at surface. show dark and light areas
-specimen prepared through thin sectioning and freeze fracturing
-observe surface detail
-beam of electrons scan the surface of specimen that is coated in metal
-electrons are released and reflected into viewing chamber
most common, carry positive charge and bond to cell structures that carry negative charge
-commonly stain the cell (acidic stains the background)
-common basic dyes include:
methylene blue, crystal violet, malachite green & safranin
1. primary stain (stains the cell)
2. mordant (holds primary dye onto the cell)
3. decolorizer (removes primary dye from gram-negative cell)
4. counter or secondary stain (recolors cells a different color that lose stain through decolorization)
1. primary: both neg & pos are purple/blue
2. mordant: cells remain purple/blue
3. decolorizer: pos cells remain purple/blue but neg cells become colorless
4. secondary or counter stain: pos cells remain purple/blue & neg cells appear pink/reddish
used to stain organisms that resist conventional staining
-high lipid concentration in cell wall which prevents uptake of dye
- uses heat to facilitate staining
-steps: primary dye (carbon fuchsin colors acid-fast bacteria red.) decolorizer (removes stain) and counter stain (methylene blue)
capsule, endospore, flagella
capsule: ex of a negative stain. allows capsule to stand out around organism
endospore: stainining enhances endospore, uses heat
flagella: staining increases the diameter of the flagella to make them more visible
diplococci: pairs of prokaryotes along a single plane
streptococci: chains of prokaryotes along a single plane
(cocci: round, bacillus: rod)
packets: division along 2/3 perpendicular planes
clusters: division along several random planes
molecules move from a region of high to low concentration, until equilibrium is reached. speed depends on concentration->the greater difference in concentration = faster the diffusion
- water, (02 and CO2) & small hydrophobic molecules pass thru via simple diffusion
transport proteins: aka permeases or carriers. they span the membrane and a single carrier transports a specific type of molecule
proton motive force: transporters allow protons into cell. protons either bring in or expel other substances
ATP binding cassette system (ABC): use binding proteins to scavenge and deliver molecules to transport complex. utlizes hydrolysis of ATP
BOTH OF THESE ARE AGAINT CONC. GRADIENT
-surrounds cytoplasmic membrane
-determines shape of bacteria
-holds cells together
-prevents cells from bursting
-unique chemical structure (distinguish gram pos from gram neg)
-much like cytoplasmic membrane but outer leaflet made of lipopolysaccharides not phospholipids
-outer memberane also called LPS layer
-LPS serves as a barrier to a large number of molecules. molecules pass though prions
-only found in a gram-negative cell
-contain o-specific side chain and lipid A
portions of the outer membrane that are medically significant
-O specific directed away from membrane. oppositite location of lipid A. USED TO DESCRIBE CERTAIN SPECIES OR STRAINS
-Lipid A: portion that anchors LPS molecule in lipid bilayer. PLAYS ROLE IN RECOGNITION OF INFECTION
P: prevents linking of glycan chains. (affects dead cells)
L: breaks bonds of NAG and NAM (affects living cells)
BOTH AFFECT PTG
the movement of a cell toward or away from a chemical stimulus.
(attraceted or repelled). it turns motor proteins
They're examples of bacterial flagella arrangement schemes.
Mono: one flagella on one end
Lopho: tuft: bunch of flagella on one end
Amphi: one flagella on each side
Peri: multiple flagella everywhere
-shorter, thinner than flagella
-composed of protein subunits called pilus
-function: join bacteria together for dna transfer & attachement by frimbrae
Small, circular DNA molecule found in bacterial cells that is capable of replicating independently from the bacterial chromosome
-encodes characteristic particularly enhances survival.
-can transfer info to other plasmids
Small rigid compartments produced by some aquatic bacteria that provide buoyancy to the cell.
-growth stops & DNA is replicated
-cell splits unevenly
-forespore becomes core & PTG between membranes forms cell wall and cortex
-moter cell proteins produce sport coat
-mother cell degrades and releases endospore
Which of the three differential stains would likely to be first used when identifying
an unknown bacterium? Explain:
Almost all bacteria can be differentiated by Gram stain into the two groups whereas only a very small percentage of bacterial species are either spore formers or acid-fast.
Bacillus Anthracis, a causative agent of Anthrax is an endospore-former.
Why does this enhance its capabilities as a biological weapon?
Bacillus anthracis spores are ideal for biological weaponry because
they can be easily produced, easily dispersed in the air, and areenvironmentally very stable.
How do you think the acid-fast nature of Mycobacterium contributes to its virulence?
The waxy cell wall of Mycobacterium protects the bacterium against phagocytosis and most antibiotics while in the host tissue. This allows the pathogen a greater opportunity to cause the disease.
Gram positive bacteria stain______ when stained with Gramstain.
Using the Schaeffer-Fultonspore stain method, spores arecolored _____
Name the counterstain in theacid-fast staining procedure.
Gram’s iodine functions as the_____ in Gram staining.
Mycobacterium and Nocardiacontain a waxy material in their cellwalls called _______ that preventsthem from being stained by manystains.
How many stains are used whensimple staining?
The negative stain allows you toobserve _______ features
When performing a streak plate,the petri plate is placed ______ onthe table.
Negative stains require heatfixing. T/F
Streaking for isolation to obtain pure samples for further testing or cultivation. Dilutes out the organisms so single colonies of bacteria are left isolated from the others.
-Organisms that do not destroy the RBCs
-Normal blood agar around the growth