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155 Cards in this Set

  • Front
  • Back
Antimicrobial Agents
Agents that kill microbes or inhibit their growth
Sterilization
Removal or destruction of all forms of microbial life
Commercial Sterilization
Exposure to sufficient heat to kill spores of Clostridium botulinum
Sanitization
Reduction of microbes present to safe levels
Microbicidal
Kills microbes
Microbistatic
Inhibits growth for a period of time
Disinfection
Destruction of vegetative pathogens present
Antisepsis
Destruction of vegetative pathogens on skin and living tissues
Degerming
Removal of microbes from an area (such as skin before a shot)
List two differences between antiseptics and disinfectants.
A) Antiseptics- Kills vegetative pathogens on living tissues.

B) Disinfectants- Kills vegetative pathogens on nonliving surfaces
Identify three different approaches in controlling the growth of microbes.
1) Killing microbes
2) Preventing microbial growth
3) Removal of microbes
Rank the following according to the resistance to antimicrobial agents:
a) Enveloped Viruses- Least resistant
b) Naked Viruses- Second least resistant
c) Typical Vegetative Bacteria- Falls in the middle
d) Mycobacteria- Third most resistant
e) Endospores- Second most resistant
f) Prions- Most resistant and most difficult to destroy
What is the ideal concentration of an antimicrobial agent?
No exact number, but the lowest effect concentration is often the best and the cheapest.
Explain how the following affect the action of chemical agents: Washing and Scrubbing, Heat, and Organic Matter.
a) Washing and Scrubbing- This reduced the original number of microbes present which would require a lower concentration of a chemical

b) Heat- Increase chemical activity

c) Organic Matter- Combine with some agents reducing activity, lowering concentration. These are typically body fluids and secretions.
List two physical methods of control that are microbistatic:
a) Cold Temperatures/Freezing

b) Desiccation (Dehydration)
Identify three targets of physical and chemical agents.
a) Plasma Membrane- Causes leakage and lysis

b) Cell Proteins- Enzymes involved in metabolism and growth are sensitive

c) Nucleic Acids- Results in disrupted function and death
Compare the action and exposure of steam heat and dry heat.
a) Steam Heat- Coagulates cell components

b) Dry Heat- Bakes or oxidizes cell components
Describe the typical conditions for sterilization using the steam autoclave.
a) 15 pounds per square inch (psi) of steam pressure

b) 121 degrees Celsius for 15 minutes. Time may depend on volume
Pasteurization
Use of high temperatures to kill all pathogens in foods
Equivalent Treatment
Using different exposure or dosage to achieve the same result
Thermal Death Time
Minimal time required to kill all bacteria in a liquid suspension at a given temperature.
Decimal Reduction Time
Time required to kill 90% of bacteria at a given temperature.
Ionizing Radiation
Production of high energy ions called free radicals that react with DNA and other components to kill microbes.
Filtration
Physical removal of microbes from a suspension using porous barrier
Desiccation
Removal of water
Membrane Filters
Remove bacteria from fluids and can sterilize heat sensitive fluids
HEPA Filters
High Efficiency Particulate Air Filters- Remove microbes from air of homes, operating rooms, and other special rooms
Lyophilization
Freeze drying of microbial cultures
Explain the action and use of X-Rays
X-Rays are waves of high energy electrons which have a microbicidal reaction with cells. These waves are a form of ionizing radiation and have shorter wavelengths than UV rays. They produce high energy ions called free radicals that react with DNA and other components in a microbe and eventually kill it.
Explain the action and use of UV light
UV rays are longer than X-rays. They cause the formation of pyrimidine dimers (nucleotides with a single carbon ring; thymine, etc.) which form abnormal bonds between adjacent DNA bases. They are used for disinfections and to kill microbes in hospital rooms and operating rooms. They typically have poor penetration because their wavelengths are longer.
Explain the action and use of Desiccation
Removes water from cells which stops metabolism. This process is microbistatic. The cells may be dried in a dehydrator or by using hypertonic environments such as 10-15% NaCl as used in pickling or 50-70% sugar as used in jams. The osmophiles (mold, yeasts) are the most resistant to this method.
High-Level Germicide
They kill endospores, all vegetative bacteria, and viruses.
Intermediate-Level Germicide
They kill all bacteria and viruses, but not endospores. Mostly used in disinfection agents such as iodine, betadine, alcohols, and hand sanitizers.
Low-Level Germicide
They kills enveloped viruses and some vegetative cells, but not endospores, naked viruses, or some vegetative cells. They can sometimes have a microbistatic.
Identify the group to which the following belong and the action and use of each: Ethyl Alcohol
Alcohols; solvent for other chemical agents, disinfection of skin and instruments, degerming skin.
Identify the group to which the following belong and the action and use of each: Hexachlorophene
Phenolics; denatures proteins and damages membranes.
Identify the group to which the following belong and the action and use of each: Lysol
Phenolics; cresol containing 3-5% phenol; denatures proteins and damages membranes.
Identify the group to which the following belong and the action and use of each: Tincture of Iodine
Halogens; 3-5% iodine dissolved in solution of alcohol; irritating to skin.
Identify the group to which the following belong and the action and use of each: Betadine
Halogens; considered part of the iodophors; antiseptics with iodine attached to organic carrier; less irritating than iodine itself.
Identify the group to which the following belong and the action and use of each: Chlorine Gas
Halogens; used to disinfect water supplies.
Identify the group to which the following belong and the action and use of each: Chloroseptic
Phenolics; 1% solution of phenol used for anesthetics.
Identify the group to which the following belong and the action and use of each: Hypochlorites
Halogens; used to disinfect restaurant equipment and swimming pools; used Clorox.
Identify the group to which the following belong and the action and use of each: Clorox
Phenolics; 10% hypochlorite solution; kills HIV and HBV.
Identify the group to which the following belong and the action and use of each: Silver Nitrate.
Heavy Metals; 1% used in the eyes of newborns to prevent gonococcal infections; not recently used often.
Identify the group to which the following belong and the action and use of each: Copper Sulfate
Heavy Metals; algaecide
Identify the group to which the following belong and the action and use of each: Zinc Oxide
Heavy Metals; antifungal agent in paints, medicines, etc
Identify the group to which the following belong and the action and use of each: Ceepryn
QUATS; used in cepacol mouthwash; damages surface membranes.
Identify the group to which the following belong and the action and use of each: Triclosan
Phenolics; antibacterial agent used in soaps; denatures proteins and damages membranes.
Identify the group to which the following belong and the action and use of each: Formalin
Aldehydes; 37% solution of formaldehyde; used to preserve specimens and as an embalming fluid.
Identify the group to which the following belong and the action and use of each: Glutaraldehyde
Aldehydes; double aldehyde molecule; can be sporocidal at extended exposures.
Identify the group to which the following belong and the action and use of each: Chlorhexidine
Biguanidines; damages membranes; used in contact solutions, surgical hand scrubs, and preoperative skin preparations.
What is cold sterilization?
The term for using ionizing radiation for sterilization. This includes gamma rays and x rays.
List three chemosterilizers and identify the use of each:
a) Ethylene Oxide- Used for plastics and other heat sensitive materials. Requires 90 minutes to 3 hours in the chemiclave. It is a suspected carcinogen.

b) Hot 30% Hydrogen Peroxide- Used to sterilize food packaging. Also called plasma (suspension of ions) sterilization and products no known toxins.

c) Betapropiolactone- Used to sterilize tissues and vaccines. It is also a suspected carcinogen.
Oligodynamic Action
Ability of low concentration to inhibit bacterial growth.
QUATS
Stands for Quaternary Ammonium Compounds; they are detergents containing ammonium ions that damage surface membranes and are more effective against Gram+ bacteria. They can be found in mouth washes and contact solutions.
Explain how the use of chemotherapeutic agents differs from the use of antiseptics and disinfectants.
They are used to prevent infections and can be used to treat diseases at the same time.
List five different actions of chemotherapeutic agents and identify one drug with each action.
a) Inhibit cell wall synthesis; penicillins, cephalosporins, Vancomycin.

b) Inhibit or damage plasma membranes; polymyxins, amphotericin B, ketoconazole.

c) Inhibit protein synthesis; streptomycin, erythromycin, tetracycline.

d) Inhibit nucleic acid metabolism; rifampin, quinolones (cipro)

e) Can be antimetabolites which are competitive inhibitors of enzymes; sulfa drugs, isoniazid (INH)
List four genera of microbes that produce antibiotics and identify the antibiotics produced by each.
a) Penicillium- Terrestrial molds that produce Penicillin G, and Griseofulvin

b) Cephalosporium- Aquatic molds that produce cephalothin and Keflex

c) Bacillus- Soil bacteria that produce bacitracin and polymyxins. Typically too toxic for ingestion and are used topically.

d) Streptomyces- Filamentous soil bacteria that produce streptomycin (derivative of azithromycin in labs), erythromycin (penicillin alternative), tetracycline, and nystatine (Monistat for yeast infections)
Chemotherapeutic Agent
Chemicals used to treat diseases and to prevent infections.
Spectrum
Groups of microbes against which an agent is effective.
Antibiotic
Means "against life", produced by microbes and major antibiotic producers in laboratories.
Semisynthetic Drug
Basic structure synthesized by microbes and additional groups or chains added in lab.
Selective Toxicity
Ability of a drug to kill or inhibit a pathogen without harming the patient. Side effects result from a lack of selective toxicity.
Anaphylactic Shock
A very severe and lethal allergic reaction in which blood supply goes down.
Drug Resistance
Ability of microbes to develop a tolerance for chemotherapeutic agents.
MRSA
Methicillin Resistant Staphylococcus Aureus
R Factors
Plasmids that contain genes for resistance
Synergistic Action of Drugs
One drug enhances the actions of another. Described as 1+1=3. The combined effect of the drugs is greater than individual effects.
Antagonistic Action of Drugs
One drug decreases the actions of another.
Antibiogram
Sensitivity profile for the microbe obtained by using representatives from different groups of drugs.
Describe two adverse reactions of chemotherapeutic agents:
a) Allergy- Immune response to drugs may cause anaphylactic shock and death. It is a common response in patients, especially with penicillins.

b) Elimination of Normal Flora- Usually normal bacteria in the colon is destroyed due to long term use of broad-spectrum agents. Can cause a superinfection in which overgrowth occurs and begins a new infection by microbes that do survive.
Explain the differences between Narrow-Spectrum drugs and Broad-Spectrum drugs.
a) Narrow-Spectrum drugs- Kills or inhibits either Gram+ or Gram- species but not both.

b) Board-Spectrum drugs- Kills or inhibits both gram+ and gram- species
Why is it not a good idea for a patient to take a broad-spectrum drug for a long period of time?
Broad-Spectrum drugs can destroy the normal flora in the body. This typically occurs in the colon with bacterium used to help create feces. And your body builds up resistance against the drug.
Identify four actions of antiviral agents and list one drug with each action.
a) Blocking uncoating of viruses; amantadine used for influenza.

b) Inhibit viral replication; interferons.

c) Inhibit synthesis of viral nucleic acids; acyclovie (Zivorax) used for herpes virus infections.

d) Inhibit the release of new viruses; Tamiflu, Relenza
List two advantages of semisynthetic penicillins.
a) Have a much broader spectrum that Penicillin G.

b) Can be given orally.
Explain the disc sensitivity test and how it is used to identify agents to which a microbe is sensitive.
a) The disc sensitivity test is a process in which an agar plate is inoculated with a broth culture and several discs with a specific concentration of antimicrobial agents are added to the plate. The plates are then incubated at 37 degrees for 22 hours.

b) The discs will leave a clear area around themselves themselves called a zone of inhibition. This zone is measured and compared to a standard table to determine sensitivity.
Identify two genetic processes that are responsible for microbes developing resistance.
a) Mutations are the first process. This includes a change in the gene which makes a microbe resistant.

b) Transfer of R factors is the second process. These R factors contain genes for resistance that can spread from cell to cell through a population.
Identify three changes in cells that can result in resistance to a chemotherapeutic agent.
a) A cell can produce an enzyme that can break down a drug, such as penicillinase.

b) A cell can have a decreased permeability to drug which keeps the drug from entering the cell.

c) A cell can alter its target site which would make it no longer inhibited by the drug.
Genetics
Study of the transmission and expression of genes.
Gene Expression
Process that includes transcription and translation.
Genome
One copy of all genes in a cell.
Transcription
Copying DNA to mRNA. First step of gene expression
Translation
Using mRNA to synthesis polypeptides (proteins) to make specific characteristics. Second step of gene expression.
Genotype
Genetic makeup or genes of an organism.
Phenotype
Appearance of an organism. Results from an expression of the genotype.
Haploid
One gene for each trait. Microbes have one unpaired circular chromosome.
Diploid
Two genes for each trait. Humans have two paired linear chromosomes.
Recombination
Process in which donor DNA replaces section of recipient chromosome in which the recipient may gain new traits.
Operon
A group of genes involved in the transcription of several related enzymes.
Explain the function of the following parts of the operon:
a) Operator- DNA sequences that initiated transcription of the structural genes. Forms the control site along with the promoter.

b) Promoter- DNA sequence to which RNA polymerase binds at the beginning of transcription.

c) Structural Genes- Sequence of genes transcribed to produce enzymes that function in a common metabolic pathway.

d) Repressor- Protein produced by a regulator gene that combines with the operator when active and represses it, blocking transcription and enzyme synthesis.
Describe the synthetic capacity of inducible operons and explain how they are turned on and off.
Inducible- These operons are naturally turned off because the regulator gene codes for an active repressor. A substrate (inducer) combines with an allosteric site on the repressor which will inactive it. This turns the operon on and polycistronic transcription of structural genes and enzyme synthesis begins. The operon is turned back off when the substrate (inducer) is broken down. This type of regulator monitors catabolic pathways. Examples: Lactose Operon.
Describe the synthetic capacity of Repressible operons and explain how they are turned on and off.
These operons are naturally turned on at all times because the regulator gene codes for an inactive repressor. The operon is transcribing structural genes and synthesizing enzymes at this point. The turn off the enzyme, the end product (arginine) will combine with the repressor to make the repressor active and it will stop transcription and production. The operon is turned on again when the end product is used up. This type of regulator monitors synthetic pathways. Example: Arginine Operon.
Why are haploid organisms more likely to be altered by a mutation?
There is only one chromosome per trait, which could be altered if that one gene were to be mutated to change.
What DNA units are typically transferred between bacteria?
a) Plasmids
b) Sections of the donor's chromosome (a few genes)
List three things that can happen to donor DNA after transfer to a recipient.
a) Donor DNA can be degraded.
b) Donor DNA remains separate from recipient chromosome and expressed transfer of plasmids such as an F factor.
c) Recombination can occur.
Briefly explain how donor DNA is transferred in each of the following:
a) Conjugation- One way transfer of DNA from donor recipient. Transfers F factors which contain the genes for transfer.
b) Transformation- The uptake of free donor DNA by recipient. Some dead cells have proteins that have not been denatured and can be taken up by recipient cells, and used in their own DNA.
c) Transduction- The transfer of DNA from donor to recipient by the use of a bacteriophage. During virus replication, the new phage will take up some of the host bacteria's DNA (transducing phage). These viruses will then inject this new DNA material into the next bacterium that will utilize those new genes.
Explain the differences between the following: F+, F-, and Hfr.
a) F+ -- Denotes that the bacteria have an independent F factor.
b) F- -- Denotes that the bacteria does not have an F factor, therefore is a recipient.
c) Hfr -- Denotes that the bacteria has an R factor attached to its chromosome.
Identify the DNA transferred and the effect in the following: F+ x F-
It starts with the donor (F+) F factor being replicated. A copy of this F factor is then transferred to the recipient through the sex pilus. The recipient (F-) now has the F factor, therefore is now a donor (F+) bacteria.
Identify the DNA transferred and the effect in the following: Hfr x F-
It starts with the donor's chromosome and the attached F factor replicating. The F factor replicates last. The replicated unit then moves across the sex pilus. While the unit is moving, the sex pilus breaks so that only the first section of the chromosome is transferred. Recombination then occurs between the donor's DNA and the recipient's DNA. In this tranfer,"", the recipient remains F-. Hfr literally means High Frequency of Recombination.
Explain how Griffith's experiments demonstrate transformation.
In the final test, the mouse was injected with living nonencapsulated bacteria and heat-killed encapsulated bacteria. The mouse died and colonies of encapsulated bacteria was isolated. Transformation occurred here because the living cells that were injected took up the genes from the dead encapsulated bacteria. The dead bacteria's DNA was not denatured; therefore it was still viable for use.
Identify the type of phage required, the relative number of transducing phage produced, the DNA transferred, and the effect of the donor DNA in Generalized Transduction.
Generalized Transduction- The use of lytic phage to transfer DNA. Any section of the donor's DNA can be transferred in this process. Lytic viruses take up the DNA from an infected host cell. The host cell ruptures and the transducing phages with the dead host's DNA infect the new cells and inject that host DNA instead of the viral DNA. This DNA can then recombine with the new host's DNA to change the genotype.
Identify the type of phage required, the relative number of transducing phage produced, the DNA transferred, and the effect of the donor DNA in Specialized Transduction.
The use of lysogenic phage to transfer DNA. Only genes next to the attachment site of the virus can be transferred. The lysogenic phage which has new chromosomes from another host cell injects its DNA into the new host cell, which attaches to the new host cell's DNA. This host cell integrates this new DNA into the genotype.
Explain the role of each of the following in genetic engineering:
a) Restriction Endonucleases- Enzymes that cut DNA so the pieces can be joined together to form recombinant DNA.
b) Cloning Vector- Self-replicating unit containing recombinant DNA
c) Cloning Hosts- Cell in which recombinant DNA can be expressed.
List two types of cloning vectors and two types of cloning hosts used in genetic engineering:
a) Cloning Vectors
1) Plasmids
2) Phage Viruses
b) Cloning Hosts
1) Bacteria
2) Yeasts
Genetic Engineering
Introduction of foreign DNA into a microbe and its replication or expression to produce a specific product.
Variation
Change in the phenotype, not due to a change in genotype.
Mutation
Change in the genotype or genes
Mutant
Altered phenotype resulting from mutation.
Spontaneous Mutation
A mutation in which there is no identifiable cause. The rate is 1 in 10^6 in bacteria. The rate is fixed per species.
Mutagen
An abnormal environment in which a mutation occurs.
Induced Mutation
A mutation due to abnormal environment.
Neutral Mutation
Altered codon codes for the same amino acid. This is a mutation without a mutant reaction.
Redundancy of the Genetic Code
For most of the amino acids, there are two or more codons that can code for those amino acids.
Missense Mutation
Altered codon codes for a different amino acid all together. This is a mutation with a mutant reaction.
Nonsense Mutation
Altered codon codes for a stop signal. This mutation can be most critical depending on where it occurs.
Insertion
Addition of one or more DNA bases
Deletion
Loss of one or more DNA bases.
Frameshifts
Changes the way transcriptase reads the bases of DNA. Shift occurs beyond the point of insertion of deletion.
Point Mutation
Addition, Deletion, or substitution of only one DNA base.
What is the relationship between mutagens and carcinogens?
About 85% of mutagens are carcinogens in lab animals.
Explain the Ames test and identify its importance.
a) Species bacteria are exposed to chemicals. Mutations can be detected by these chemicals. If the mutations are detected, the chemical is a mutagen.
b) It is most useful for screening for carcinogens before use on lab animals.
List five major characteristics for the fungi.
a) They are eukaryotes.
b) They achieve nutrition by absorption.
c) They are haploid.
d) Most have cell walls made of chitin.
e) They are generally aerobes or facultative anaerobes.
Saprobe (Saprotroph)
Group that gets their nutrients from dead or decaying matter.
Mycosis
A fungal infection.
Dimorphic Fungus
Group that grows as mold (multicellular) in environment and yeast (unicellular) in the body. Temperature differences cause the changes.
Hyphae
Tubular filaments that comprise multicellular fungi.
Septate Hyphae
Structural type of hyphae that have partitions called septa.
Nonseptate Hyphae
Structural type of hyphae that have no partition. They contain multinucleated cytoplasm.
Mycelium
Growth of mold containing all of its hyphae. Equivalent to bacterial colonies.
Vegetative Hyphae
Functional type of hyphae that are found close to substrates and absorb nutrients.
Aerial Hyphae
Functional type of hyphae that are involved in reproduction. Their spores give mold its green color.
Karyogamy
The process of positive and negative nuclei fuse to form diploid zygote.
Teleomorphs
Fungi that produce both sexual and asexual spores. Most fungi are teleomorphs.
Anamorphs
Fungi that produce only asexual spores.
List four morphological groups of fungi.
a) Yeasts- Unicellular fungi
b) Molds- Produce wooly growths
c) Fleshy Fungi- Produce large fruiting bodies made of compacted hyphae
d) Dimorphic Fungi- Mold in the environment and yeast in the body
Asexual Spores
These spores are formed by mitosis in cells or by the hyphae of one fungus. The germination process produces fungus. The new spores are genetically identical to the parent. They are also less resistant than bacterial endospores.
Sexual Spores
These spores are formed by recipient and donor strains. The fungus produced in germination has properties of both mating strains. The spores are formed by karyogamy and meiosis. Meiosis produces the new haploid nucleic and sexual spores.
Sporangiospores
Asexual spores formed in bulblike sporangium at the end of aerial hyphae.
Conidiospores
Asexual free spores not enclosed in a sack. They are formed by pinching off tips of aerial hyphae or segmentation of existing hyphae. There are several different specific types.
Arthrospores
Asexual spores that are rectangular. They are formed by segmentation of septate hyphae.
Blastospores
Asexual spores that are produced by budding. Generally occurs in yeasts.
Pseudohyphae
Chains of blastospores.
Describe three types of sexual spores produced by fungi.
a) Basidiospores- Spores formed at the tips of club-shaped hyphae called basidia.
b) Ascospores- Spores formed in a sack called an ascus.
c) Zygospores- Spores that develop from a zygote. They form from the fusion of haploid cells.
List four divisions of true fungi and list one representative of each:
a) Zygomycota- a division including nonseptate hyphae that are called conjugation fungi. They produce sexual spores, or Zygospores. Rhisopus nigricans is an example, otherwise known as black bread mold.
b) Ascomycota- A division including septate hyphae called the sac fungi. They produce Ascospores. Aspergillus, fungal truffles (tree root fungi), and typically baking and brewing yeasts are examples.
List four divisions of true fungi and list one representative of each:
c) Basidiomycota- A division including septate hyphae called the club fungi. They produce basidiospores. Mushrooms and puffballs are examples.
d) Deuteromycota- a division including fungi that are called fungi imperfecti. They produce no sexual spores and contain some human pathogens. Examples are Candida albicans and Phytophthora infestants which is an aquatic fungus that causes potatoe blight.
e) All of these are identified by the type of sexual spores that they produce.
Fungi Imperfecti
Alternate name for Deuteromycota. They produce no sexual spores. They are all Anamorphs.
Opportunistic Fungi
Can cause infection only under unusual conditions such as elimination of normal flora or with a weakened immune system.
Mycorrhizae
A group of fungi that have mutualistic relationship absorbing water and minerals on roots of plants. Literally means fungus root.
Identify two opportunistic fungi and one disease caused by each.
a) Candida albicans- Causes thrush and vaginitis
b) Pneumocystis carinii- Causes pneumonia in AIDS patients. (PCP)
List five beneficial effects of the fungi.
a) Some are edible (mushrooms, truffles)
b) Some produce antibiotics such as Penicillium
c) Some are decomposers that recycle nutrients.
d) Some produce products of fermentation (yeasts)
e) Some are Mycorrhizae
List three harmful effects of fungi
a) Some cause infections in humans (mycoses)
b) Some cause diseases in plants
c) Some produce toxins
Superficial Mycoses
Fungal infections that invovle the very outer layer of skin and hair. Tinea versicolor is an example
Cutaneous Mycoses
Fungal infections that live in the tissues of the skin, hair, and nails. They are able to break down keratin (keratinase). Dermatophytes are fungi that produce keratinase and are involved in cutaneous mycoses. Tinea Capitis (ringworm) and tinea pedis (athlete's foot) are examples.
Subcutaneous Mycoses
Fungal infections that involve tissues below the skin. Sporotrichosis is an example.
Systemic Mycoses
Fungal infections that involve internal organs. Most of these fungi begin in the lungs, but do not necessarily stay there. Histoplasmosis is an example, which is similar to tuberculosis.