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Microbiology Exam 2


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modification in the base sequence of DNA in a gene resulting in an alteration in the protein encoded by the gene.
What is a negative result of mutations?
Cause cancer
Properties of a cell determined by its DNA composition
Mutant microorganism that required an organic growth factor.
Organisms that use light as a source of energy
Parent Strain
Refers to the original strain of a bacterium used in an experiment; term is often used in place of wild-type strain.
The characteristics displayed by an organism in any given environment.
Spontaneous Mutations
Discredited theory that organisms can arise from non-living matter.
What are 3 types of spontaneous mutations?
Base substitution
Removal or addition of nucleotide
Transposable elements
How do spontaneous mutations occur
Without the addition of agents.
Base Substitution
Substitution that doesn't normally occur. Mix up of the base pairs.
Removal or Addition of Nucleotide
Also called frameshift mutation.
Transposable Elements
Genes that can jump down the chromosome. Jumping genes.
Induced Mutations
Mutation that results from the organism being treated with an agent that alters its DNA. Caused by humans.
Chamical Mutagens
Any chemical treatment that alters a purine or primidine. One is used to inhibit HIV.
Jumping genes are added to culture and form mutations which change the DNA structure.
A way to induce mutations with UV and XRAY.
Two types of radiation
UV and XRay
Are pure cultures really pure?
No. There will be mutants.
Natural Selection
Mutants can respond to the changing environment. Selection by the environment of those cells best able to grow in that environment.
Name 3 types of mutant selection.
Direct Selection
Indirect Selection
Conditional Lethal Mutants
Direct Selection
Technique of selecting mutants by plating organisms on a medium on which the desired mutants but not the parent will grow.
Indirect Selection
Technique for isolating mutants and identifying organisms unable to grow on a medium on which the parents do grow; often involves replica plating.
Conditional Lethal Mutants
Mutant that under some environmental conditions will grow, with lethal results, but under other conditions will not grow.
DNA-mediated Transformation
Actual pieces of DNA from a lysed cell insert themselves into a new bacterium.
Bacteriophage (virus) infects the bacteria. Virus attaches to tcell wall of bacteria and dumps DNA into the cell.
A virus that infects bacteria.
Means by which plasmids are transferred. Most common way of transfer in gram (-) rods.
Plasmid Transfer
Contact between donopr and recipient cells.
Activation of DNA transfer
Plasmid transfer
Synthesis of functional plasmid in the recipient and donor cells.
Extra chromosomal material DNA that is independent of the chromosome. Most baceria do have plasmids.
Not part of the cell's chromosome.
Pieces of DNA that are capable of replicating. Contains an origin of replication.
Host Range
The range of cell types that a pathogen can infect.
Two variations of the host range.
Wide and Narrow
R Plasmids
Resistant plasmids. Plasmids that encode resistance to one of more antimicrobial medications and heavy metals.
R Genes
Part of an R Plasmid
Resistance Transfer Ractor (RTF)
Part of the R Plasmid that codes for the transfer of the plasmid to other bacteria by conjugation.
What are 2 parts of the R Plasmids?
R Genes
Resistance Transfer Factor
What does Wide Host Range mean?
_____ Can multiply in many different species of bacteria.
Hospital Environment
A place where there are many resistant bacteria.
Science that studies organisms in order to arrange them into groups. Organisms with similar properties are grouped together.
Characterizing organisms
Process of arranging organisms into similar or related groups primarily to privide easy identification and study.
System of assigning names to organisms; a component of taxonomy.
Name of the Taxonomic Hierarchies of Prokaryotes
Domain - Kingdom -
Phylum (Division) - Class -
Order - Family -
Genus - Species.
What are the 3 domains
What book shows the hierarchy of Bacteria?
Bergeys Manual of Systematic Bacteriology
What are 4 microscopic phenotypic characteristics?
Size and shape
Gram stain
Special stains
Gram Stain
A quick, easy test to differentiate gram (+) from gram (-). Can be diagnostic.
What is the first step in identifying unknown?
Microscopic Morphology.
Who invented the microscope?
What is the second level of identification?
Metabolic Differences
What are culture characteristics?
The characteristics we see on the plate of agar.
What type of plate is used to grow staph and strep cultures?
Blood agar plate
Characteristics of Serratia marcescens
Red, gram (-) rod.
What are the characteristics of Pseudomonas aeruginosa?
Lime green, gram (-) rod. Fruity smell.
What are the characteristics of Streptococcus pyogens?
Beta Hemolytic group A strep. Causes hemolysis on blood agar plate.
What is one biochemical test?
What is dichotomous key?
Like a flow chart. Used to identify unknowns.
What are 3 commercial biochemical tests?
A Catalase (+) bacteria.
A catalase (-) bacteria.
Means of identification. Antibody/Antigen Reactions.
Streptococcus pyogenies
Causes strep throat
Who discovered the identification of the strep groups?
Fatty acid analysis
A cumbersome research method done in research areas that is expensive.
Gas Chromotography
The method of viewing the results of fatty acid analysis.
Do you need the living organism to identify an organism genotypically?
No. The organism does not need to be living.
Name 3 genotypic tests.
Nucleic Acid Probe
Polymerase Chain Reaction
Sequencing Ribosomal Unculturable Organisms.
Single stranded DNA
A genotypic test that can be done on throat cultures.
Test done to detect gonorrhea and chlamidia.
A strain that has a characteristic biochemical pattern different from other strains; also called a biovar.
Serological Typing
Type based on cellular and flagella antigens.
A strain that has a characteristic antigenic structure that differs from other strains; also called a serovar.
Antibiotic susceptibility pattern; used to distinguish different bacterial strains.
Antibiograms in hospital
Statistical data that helps a doctor treat diseases.
Susceptibility Patterns
Listing of conditions in various hospitals and their rate of occurence.
Also, resistance in a given population. Trends.
Anaerobic Chemoorganotrophs
Organisms that oxidize organic compounds such as glucose to obtain energy.
Anaerobic Respiration
The terminal electron acceptor can not be O2; usually sulfur or sulfate.
Three characteristics of Sulfur- and sulfate reducing bacteria.
Rotten egg hydrogen sulfide
Mud & water turn black
Desulfovibrio (organism)
How do anaerobic chemoorganotrophs oxidize glucose?
By fermentation
Name an example of an anaerobic chemoorganotroph.
Name 4 characteristics about Clostridium
Gram (+) rods
Can form endospores
Most found in soil
Cause tetanus, gangrene, botulism
Lactic Acid Bacteria
Generate lactic acid as a major end product of their fermentative metabolism.
Name some lactic acid bacteria
Obligate Fermentors.
Use pyruvate at final electron acceptor to produce lactic acid. They don't utilize O2.

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