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Microbio Exam 2


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Mycobacterium TB
Mycobacterium tuberculosis
rod, obligate aerobe
acid fast
cell wall has a large amount of lipids
Plasmodium vivax/ovale/falciparum
caused by parasite
carried by female mosquito
can cause anemia
Salmonella enterica
gram -, rod shaped
facultative anaerobe
don't use antibiotics
in food- meat and poultry
Lyme Disease
Borrelia burgdorferi
spirochete, gram -, microaerophilic (little air)
bullseye rash
death is rare
carried by ticks, deer, raccoons
Clostridium botulinum
gram +, rod shaped, obligate anaerobe, produce endotoxins
foodborne, wound, infant
boil food
Order- Mononegavirales
Family- Rhabdoviridae
Genus- Lyssavirus
bullet shaped
first symptoms- flu like
then attacks CNS
Enterococcus faecalis
gram + cocci
gastrointestinal tract, vagina, mouth
nosocomial infections
Pseudomonas aeruginosa
gamma Proteobacteria- gram - aerobic rods and cocci
Order- Pseudomonadales
gram -, aerobic, rods or cocci
Enterobacter aerogenes
gamma Proteobacteria- facultative gram - rods, enterics
urinary tract infections
soil, skin, mucus membranes
move by axial filaments
Treponema, Borrelia
Aquatic, animal parasites
helical (like a spring), gram -
Gram - aerobic rods and cocci
Pseudomonas, Legionella, Neisseria, Rhizobium
soil, water, animal parasites
Facultative Gram - rods, enterics
Escherichia, Salmonella, Klebsiella, Vibrio, Enterobacter, Yersinia
soil, plants, animals- respiratory, coliforms
Anaerobic Gram - rods
animals and insects, intestinal
Aerobic, nitrifying, chemoautotrophs
Nitrosomonas, nitrobacter
soil, gram -, agricultural
Endospores, aerobic to anaerobic
gram + rods and cocci
Bacillus, Clostridium
soil, animal intestinal tract
Regular, Gram + rods
Lactobacillus, Listeria
dairy products
Irregular, gram + rods
human pathogens,pleomorphic
soil, plants, animals
gram +
Gram + cocci
Staph, Strep, Enterococcus
soil, skin, mucus membranes
Binary fission
cell division, cell divides along median
Physical requirements for microorganisms
Temp., pH, osmotic pressure,
Chemical requirements for microorganisms
carbon, nitrogen, sulfur, phosphorus, trace elements, oxygen, organic growth factors
Chemically defined media
media whose exact chemical composition is known
Complex media
exact chemical composition is not known
Generation time
the time required for a cell to divide
Bacterial growth curve
lag phase- little or no cell division
log phase- much cell growth
stationary phase- period of equilibrium
death phase- cells die
plate counts
counting colonies from plates
Serial dilutions
concentration of bacteria reduce ten-fold as dilution continues
Pour plates
petri plates are inoculated with each ten-fold dilution, count of colonies can be used to calculate original number in sample
Spread plate
Inoculum is spread over the entire surface of the agar plate
water is passed through a membrane filter which bacteria can't pass through, filter is then plated
Medium becomes cloudy and measured with spectrophotometer to measure amount of cells using a log
the removal or destruction of all forms of microbial life
destruction of vegetative pathogens
use chemicals, boiling, steam
destruction of vegetative pathogens on living tissue
use of chemicals (alcohol)
removal of microbes from a limited area
treatment to lower microbial counts on eating and drinking utensils
Physical methods of control
heat (moist heat, pasteurization, dry heat), filtration, low temps., high pressure, desiccation (absence of water), osmotic pressure, radiation
Chemical methods of control
phenols/phenolics, biguanides, halogens, alcohols
carbolic acid, rarely used as it irritates the skin
chemically altered phenol, injure lipid containing plasma membrane causing leakage
used for disinfecting pus, saliva, feces
used for control on skin and mucous membranes
injures plasma membrane
iodine, chlorine
solution in aqueous alcohol
kill bacteria and fungi but not endospores and nonenveloped viruses
Surface-Active Agents
surfactants, decrease tension among molecules of a liquid
soaps, detergents
Quaternary Ammonium Compounds (Quats)
most widely used surface-active agents, positively charged,
formaldehyde, form covalent cross links
hydrogen peroxide, oxidizes cellular components
info that codes for characteristics
actual, expressed properties
DNA polymerase
enzyme that synthesizes DNA by copying template
Semiconservative replication
new double DNA strand has one original DNA strand from parent
DNA replication
1. DNA is unwound and stabilized, replication fork forms
2. one new DNA strand is synthesized continuously as DNA polymerase moves toward replication fork
3. RNA primer starts synthesis on 3' end
4. DNA polymerase removes RNA primer
5. DNA ligase joins newly made DNA fragments
symthesis of complementary strand of RNA from DNA template
1. RNA polymerase binds to one strand of DNA
2. RNA polymerase assemles free nucleotides into new chain, base pairing
3. RNA polymerase continues along DNA
4. RNA synthesis continues until reaches terminator
5. RNA polymerase and mRNA released from DNA
protein synthesis
tRNA travels along codons to assemble amino acids into polypeptide chain, continues until 3 nonsense codons are reached
inhibits gene expression and decreases synthesis of enzymes
turns on trascription of gene
change in base sequence of DNA
spontaneous and random,
Types of Mutations
Base insertions, deletions or substitutions
Cause of Mutations
chemicals, ionizing radiation, UV radiation
Genetic recombination
exchange of genes between two DNA molecules to form new combinations of genes on a chromosome
genes are transferred from one bacterium to another as "naked" DNA in solution- direct uptake
new DNA obtained via conjugation tube (sex pilus), from another cell, often involves plasmids
bacterial DNA is transferred from a donor cell to a recipient cell inside a virus (bacteriophage)
small segments of DNA that can move from one region of a DNA molecule to another
can have antibiotic resistance
Recombinant DNA procedure
1. Gene of interest is inserted into vector DNA
2. Vector is taken up by a cell where it multiplies
3. Cell is grown to form a clone
4. From clone gene of interest is harvested and can be inserted into another vector
5. If gene is expressed its protein product can be harvested and used
Restriction Enzymes
DNA cutting enzymes that exist in many bacteria
recognizes and cuts only one particular sequence of nucleotide bases, cuts sequence in the same way each time
Restriction enzymes action
1. base sequences are the same but run in opposite directions
2. staggered cuts leave single-stranded DNA at ends (sticky ends)
3. two fragments of DNA from different sources with same sticky ends they can be spliced
4. sticky ends first by hydrogen bonding
5. DNA ligase used to covalently link DNA
Polymerase Chain reaction
technique where small samples of DNA can be quickly amplified for analysis
PCR process
1. each strand of target DNA serves as a template
2. four nucleotides and DNA polymerase, short pieces of nucleic acid (primers) are also added (complementary to ends of target DNA)
3. Hybridize to fragments to be amplified
4. polymerase synthesizes new complementary strands
5. DNA is heated to convert all new to single strands for a new template
Colony hybridization
identifying cells that carry cloned gene, DNA probes are synthesized, DNA probe is labeled with a radioactive element so its presence can be determined
Southern blotting
human DNA is filtered and exposed to a radioactive probe for gene of interest, fragments are then separated through the gel
Three Domains
Taxonomic Hierarchy
science that studies blood serum and immune responses that are evident in serum
Methods used for classification
morphological characteristics
differentail staining
biochemical tests
phage typing
fatty acid profiles
flow cytometry
DNA base composition
DNA fingerprinting
ribosomal RNA sequencing
polymerase chain reaction
nucleic acid hybridization
Dichotomous keys
identification method based on successive questions each with two possible answers
maps that show evolutionary relationships among organisms
Eukaryotic, vegetative structures, hyphae (long rows of cells), can reproduce sexually or asexually, heterotrophic, mainly aerobic, antibiotics not effective
Superficial Mycoses
Ringworm, spreads out in all directions, causes hypersensitive immune reactions, red rings
Tinea capitis- ringworm of scalp
Tinea pedis- ringworm of feet
Systemic Mycoses
fungal infection within the body, enter through respiratory tract, id is difficult
more prevalent because of AIDS, drug treatment
kingdom- protista
reproduction is sexual or asexual
can form protective cyst
aerobic heterotrophs
African Sleeping Sickness
transmitted via tsetse fly
affects CNS
Giardia lamblia
intestinal infection
"travelers diarrhea"
Trichomonas vaginalis
move via flagella
move via pseudopodia
Entamoeba histolytica
infect large intestine
amoebic dysentery
diagnosed by examining fresh stool
move via cilia
no serious pathogens
all parasites
lack locomotor structures
all are disease causing
sickle cell disease offers some resistance
Composed of DNA or RNA, protein coat, sometimes an envelope
intracellular parasites
lytic cycle- new virus production, cell lyses
lysogenic- prophage state, viral DNA integrates with host DNA and becomes lytic later
Steps of Virus infection
1. Attachment- receptor on cell/virus
2. Penetration, uncoating
3. Replication of genome
4. mRNA, protein synthesis
5. maturation and release by budding
Catalase test
place hydrogren peroxide on sample- if small bubbles form organism is catalyst positive-is able to produce a catalase (enzyme) to detoxify hydrogen peroxide- aerobic
Oxidase Test
identifies the presence of cytochrome oxidase in aerobic electron transport chain
shows is organism is anaerobic
Nitrate Reduction test
identifies is bacteria can transfer electrons to nitrate at the end of an electron transport chain- anaerobic
SIM medium
combination medium- used to test multiple properties
tests for sulfur reduction, indole production and motility
differentiates Salmonella and Shigella
UV radiation
UV did not inhibit growth of cells, bacteria was able to develop mutation
UV light was not able to penetrate the paper to stimulate cells to grow
Fluorescence test
If bacteria can grow on ampicillin plate and fluoresce it is transformed and contains the plasmid
Action of disinfectants
measure the space between paper soaked in disinfectant to see how effective it is against P. aeuroginosa

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