Microbiology Chapter 1
study of micro-organisms
living, mostly unicellular microscopic organisms
an abnormal state in which the body is not properly adjusted or incapable of performing normal functions
the branch of microbiology; dealing with human pathogens (disease causing agents)
Scope of course
1. Study of different groups of microbes 2. Pathogenic properties of microbes
3. host defenses 4. control of microbial growth
5. surgery infections diseases 6. importance of lab course.
Primitive cells, no nuclear membrane, no nucleus, no membrane bound organelles.
Cells divide by binary fission.
Groups of Procaryotes:
Bacteria, Mycoplasmas, Rickettsia, Chlamydia
found in all natural environment on humans
can be pathogen
exists in 3 shapes: Cocci (round), Bacillus(rod), Spiral
smaller in size than bacteria
shapes are atypical, no cell wall
cause respiratory & urogenital infections in humans (bladder STD's)
very small bacteria that have causative agents of typhus & other febrile diseases in humans.
like viruses, can only grow inside living cells
transmitted by mites, ticks or lice.
cocci, small parasitic bacteria like a virus
requires biomechanisms of another cell in order to reproduce
#1 causing STD
cells we're familiar with: plants & animals
have nucleus and nuclear membrane
Groups include: fungi, algae, protozoa
Fingi is found in bad food, pharmaceutical lack chlorophyll (can't make own food). They are Saprophytes; depend on food from others. Divide by asexual & sexual reproduce. Have cell wall & cellulose cell wall. both unicellular (single celled) & multicellular Unicellular: yeast (pathogens) Multicellular: Mold(pathogens) & mushrooms(produce toxins, damage GI)
1st in food chain, Autotrophs: they can make their own food bc they have chlorophyll. NOT A HUMAN PATHOGEN
Uses photosyntheses; traps sunlight
unicellular and multicellular
(see notebook for this card)
*Parasite* : single celled: protozoa have structures used to move around
ciliata: move by cilia ; flagellate, amoeba, sporozoa
multicellular: Helmiths, nematodes, cestodes, trematodes
living, non cellular, pathogenic organisms; simple in structure; DNA or RNA virus. outside of DNA/RNA is protein coat
small in size; obligate intracellular parasite (have to be inside a living cell)
Size of Micro-organisms
2. History of Micro
Demonic & Humoral Theory
Demonic: no terminology then only visual; thought that supernatural phenomenon caused by demons
Humoral: body fluid theory, natural thing
Robert Hook Discovery
Englishman discovered 1st single microscope. Didn't see any live things. Microscope x270 magnification
Germ theory of Diseases
microorganisms can invade other organisms and cause disease
Theory of Spontaneous Generation
living organism arose from non-living things
John Needham (1745)
challenged Redi's findings. 1st who spoke of spontaneous generation. life could come from non-living things. left chicken broth in a flask open & presence of life appeared even when he heated & sealed the bottle.
He actually didn't heat it long enough to kill all the microbes
Put meat in one jar with a lid and another without a lid. Open one was covered in maggots, closed was not. The lid was though disproving Needhams spontaneous generation theory. Flies left eggs on the lid
Theory of Biogenesis
1st proposed by Virchow who said living things can arise from pre-existing living cells.
Louise Pasteur: created gooseneck flask, if no air comes in living object stays. showed & supported theory.
by Louis Pasteur; heating process to kill all inactive bacteria in milk, fruit juices, alcohol. Increase temp to 62.8 celsius for 30 mins.
Louis also discovered vaccine for Cholera.
Also by Louis
chemical breakdown of fruit juices into alcohol.
sugar + yeast in absence of air = alcohol
Alcohol + yeast in air = acetic acid vinegar (alcohol goes bad)
single type of microorganism can cause a single type of disease. -Same pathogen must be present in every case of disease. -Pathogen must be isolated from disease & host & grown in pure culture (by itself) - pathogen in culture must cause the disease when inoculated into a health animal. -pathogen must be isolated from the 2nd set of diseased experimental animals & shown to be original organism. Transmission of anthrax between cows & humans which proved the germ theory;
discovered by Edward Jenner. People in village were sick with pox except for milk maid; tested her blood & she had antibodies. Vacca=Cow
Vaccine is a resistance to a particular disease conferred by inoculating w a vaccine. Prepared from a killed weakened pathogen
Sepsis=infection ... Anti-infection.
Ignaz Semmelweis: encouraged hand washing & cleaning instruments
Joseph Lister: father of antiseptic surgery, used carbolic salts and acids to clean instruments
Study of Immunity
study of viruses, after discover of microscope
Chemical treatment of disease.
discovered 1st synthetic drug artificially made in the lab
natural drug discovered by accident; when he was working with staphylococcus discovered penicillin from penicillium in the mold.
Microbial Genetics & Molecular Biology
Microbial Genetics: how microorganism inherit traits
Molecular Biology: how genetic information is stored inside DNA and how DNA makes protein
(see notebook for hierarchy)
Taxonomy: signs of classification and identification of organisms.
Kingdom classification system
In 1969 Robert Whittaker created 5 kingdom classifcations
1. Monera: *only procaryote group* ancestors to all eukaryotes, mostly unicellular & prokaryotic.
2. Protista: mostly unicellular organisms, eukaryotic, includes protozoa & algae
3. Fungi: heterotrophs, can't make own food absorb it
4. Plantae: multicellular phototrophs (make own food)
5. Animalia: multicellular ingestive heterotrophs
Domain Classification systems
Carl Woese: based this on modern techniques in biochem and molecular biology
2. Archaeo bacteria
live in extreme environments b/c their cell walls can't live in oxygen, carry out unusual metabolism;
Methanogens- metabolism produces CH4 gas (methane) Halophiles- high salt environment ;
Thermoacidphile-need high temps and high acid conditions
Naming micro organisms
always has a genus name, then species name. Genus name may be abbreviated ex: S. aureus. always underlined or italic
example: Staphylococcus aureus - Staphylococcus genus word meaning cluster of cocci
aureus is species name meaning golden (look yellowish)
a species of bacteria that are a common cause of infection. found on skin, upper respiratory.
clusters of cocci that grow in clusters on artificial media in lab.
many strains of S.Aureus; most killed by antibiotic methicillin but not the strains. MRSA is methicillin resistant s. aureus.
(E.coli) another species of bacteria.
Coli- species meaning these bacteria live in the intestines (colon) or can infect the colon
There are strains of E.Coli; serious & fatal food infection.
Each different group within a species
used microscope to see weaving of materials he wanted to see what was in tears, saliva, rain, pond water. 1st to see live biological specimens.
refers to evolutionary history
Binary (transverse) Fission
bacteria divide by budding or fragmentation
binary fission; method of prokaryote division.
Phases of Bacteria Growth
(know 4 stages and what happens)
1. Lag Pase
2. Log Phase
3. Stationary Phase
4. Decline (death phase)
when cells aren't dividing; making new cytoplasm, DNA; Elongate (become longer); lag phase is the TIME INTERVAL
between growth curves
when the cells are actively dividing at a steady rate aka EXPONENTIAL GROWTH PHASE.
bacteria are susceptible at this stage to antibiotics and radiation.
1-3 hours for growth phase to complete
growth of population stops because nutrients are used up and toxic materials build up.
same # of cells dividing same # of cells dying
Decline phase (death phase)
when population is dying
structure of prokaryotic bacterial cell
aka slime layer or GLYCOCALYX
Located external to the cell wall
structure; sticky, gelatins polysaccharide or polypeptide can be both.
functions: gives protection for bacteria against any adverse condition, protects from phagocytosis (cell eating)
help bacteria attach to any surface. gives virulence (power to become pathogenic)
hollow, whip like organ, for movement attached to cell membrane helps bacteria move
structure: consist of 3 parts, long filament attached to hook attached to basal body
depend on food from others