Microbiology Exam 2
Terms
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- Mutation
- 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
- Genotype
- Properties of a cell determined by its DNA composition
- Auxotrophic
- Mutant microorganism that required an organic growth factor.
- Phototrophic
- 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.
- Phenotype
- 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.
- Transposition
- Jumping genes are added to culture and form mutations which change the DNA structure.
- Radiation
- 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.
- Transduction
- Bacteriophage (virus) infects the bacteria. Virus attaches to tcell wall of bacteria and dumps DNA into the cell.
- Bacteriophage
- A virus that infects bacteria.
- Conjugation
- 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. - Plasmids
- Extra chromosomal material DNA that is independent of the chromosome. Most baceria do have plasmids.
- Extrachromosal
- Not part of the cell's chromosome.
- Replicons
- 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.
- Taxonomy
- Science that studies organisms in order to arrange them into groups. Organisms with similar properties are grouped together.
- Identification
- Characterizing organisms
- Classification
- Process of arranging organisms into similar or related groups primarily to privide easy identification and study.
- Nomenclature
- 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
-
Bacteria
Archaea
Eukarya - 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
Capsule - 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?
- Lewanhook
- 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?
- pH.
- What is dichotomous key?
- Like a flow chart. Used to identify unknowns.
- What are 3 commercial biochemical tests?
-
API
Entertube
Vitek/Microscan - A Catalase (+) bacteria.
- Staphylococcus
- A catalase (-) bacteria.
- Streptococcus.
- Serology
- Means of identification. Antibody/Antigen Reactions.
- Streptococcus pyogenies
- Causes strep throat
- Who discovered the identification of the strep groups?
- Lancefield.
- 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.
- Hybridization
- Test done to detect gonorrhea and chlamidia.
- Biotype
- 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.
- Serotype
- A strain that has a characteristic antigenic structure that differs from other strains; also called a serovar.
- Antiobiogram
- 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.
- Clostridium
- 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
-
Streptococcus
Enterococcus
Lactococcus
Lactobacillus
Leonconostoc - Obligate Fermentors.
- Use pyruvate at final electron acceptor to produce lactic acid. They don't utilize O2.