Microbiology comprehensive review Flashcards

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created 12 years ago by kyladavis
Introduction and History: 1-8 Brief survey of life forms: 9-19 Anatomy of Cells: 20-32 Microbial growth and metabolism: 33-58 Microbial Genetics: 59-66 Immunology: 67-72 Immune system disorders: 73-75 Diagnostic tests: 76-79 Principles of disease: 80-104 Microbial control: 105-129
updated 12 years ago by kyladavis
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Define and compare the theories of bio-genesis and spontaneous generation

Bio-genesis is the principle that living organisms develop only from other living organisms and not from non-living matter. Spontaneous generation states that living organisms develop from non-living matter.


List the steps of Koch's Postulates and describe what they were designed to do

Can demonstrate the relationship of an organism to a disease.
1. The microorganism identified as the etiologic agent must be present in every case of the disease.
2. The etiologic agent must be isolated and cultivated in pure culture.
3. The organism must produce the disease when inoculated in pure culture into susceptible animals.
4. A microorganism must be observed in and recovered from the experimentally diseased animal.


Define germ theory

States that microorganisms can invade the body and can cause certain diseases.


List the major contributions to microbiology by the following people:
Louis Pasteur

Wine spoilage



Insisted on hand washing



Proposed aseptic surgical techniques to reduce sepsis. He was the first to use phenol (carbolic acid) as a disinfectant



Demonstrated a non-cellular form of immunity which is called chemical or humoral immunity.


Avery,McLeod and McCarty

Determined that DNA was the genetic material in a cell



Using characteristics of organisms to identify, name and classify organisms


Purposes of taxonomy

To make it easier to study organisms if they are organized into groups or categorized, to provide a method of determining relationships between newly discovered groups, the show similarities between existing groups, to provide a universal language for communication between scientists, and to provide insight into possible evolutionary relationships between existing and extinct forms.


Carolus Linnaeus

Developed the original scientific classification system. Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species. Do king play chess on fairly grey Sundays?


Nomenclature- Scientific names

Two names- The 1st name is the genus (always capitalized); the 2nd name is the species (do not capitalize). Underline each part of the name; the space between is NOT underlined. Underlining is not necessary if italics are used.


Three Domains-

Carl Woese- Eukarya, Bacteria, Archaea



Eukarya contains 4 kingdoms: Plantae, protista, fungi and animalia. All organisms in this domain have eukaryotic cells, nucleus.



All pathogenic and some non=pathogenic prokaryotes, as well as photoautotrophic prokaryotes. These have peptidoglycan in their cells walls, no nucleus, and no kingdom classification.



Contains prokaryotes without peptidoglycan in their cell walls. Many live in extreme environments. No nucleus, no peptidoglycan.



lack cellular organization and incapable of performing most characteristics of life, they are not considered to be living organisms, and are not classified into domain or kingdom. Neither eukaryotic or procaryotic. Their basic structure is DNA or RNA surrounded by a protein coat. With out host cell, this does not function.


Naming of Viruses

Genus and species names are NOT underlined for viruses.
Family names end in -viridae
Genus names end in -virus
Species are usually designated by a descriptive common name such as Hep A virus, etc.


Brief Survey of Life forms

fill in charts later


Name the major differences between eucaryotic and procaryotic cells.

1. Prokaryotic and eukaryotic cells are similar in their chemical composition and chemical reactions
2. Prokaryotic cells lack membrane-enclosed organelles (including a nucleus)
3. Peptidoglycan is found in prokaryotic cell walls but not in eukaryotic cell walls
4. Eukaryotic cells have a membrane-bound nucleus and other organelles.
5. Cell division in eukaryotic cells is usually by mitosis, while binary fission is the common division in prokaryotic cells.


Define Streptococci

Divide and remain attached in chain-like patterns



Those that divide in multiple planes and form grapelike clusters or broad sheets



Cocci that appear in pairs after division



vertically aligned cells



Helical shape like a corkscrew and fairly rigid bodies



Can have many shapes, not just one.



A complete, intact, infectious virus



A virus that infects bacterial cells.
Head: capsid containing genetic material
Tail: Tube like extension from head
Tail Fibers: Extensions of tail used for attaching to bacteria surface. Tail recoils like syringe to inject nucleic acid into bacteria.



An infectious agent consisting of a self replicating protein, with no detectable nucleic acids.



A resting structure formed inside some bacteria


Know the structural makeup of a typical virus

A virion is a complete, fully developed, infectious viral particle composed of nucleic acid (DNA or RNA) and surrounded by a protein coat called a capsid that is composed of small protein sub-units called capsomeres, which protect it from the environment and is a vehicle of transmission for one host cell to another. Viruses are classified by differences in the structures of these coats.


Know how prions work and examples of diseases caused in humans

Diseases are caused by the conversion of a normal host glycoprotein into an infectious form. The human diseases known are Kuru, Creutzfeldt-Jakob disease (CJD), Gerstmann-Straussler- Scheinker syndrome and fatal familial insomnia.


Name the 4 major organic compounds necessary to maintain life of all organisms, the major functions and the monomer of each.

Carbohydrates, lipids, proteins and nucleic acids



major functions: Deoxyribose is a building block of DNA, other sugars are needed for cell walls. Simple carbs are used in synthesis of amino acids and fats or fat-like substances which are used to build cell membranes and other structures. Function as food reserves. Principal function if to fuel cell activities with a ready source of energy.
monomer: monosaccharides like glucose



Major functions: Lipids are essential to the structure and function of membranes that separate living cells from their environment. Provides the structure of membranes and some cell walls and function in energy storage.
monomer: glycerol, fatty acids.



major functions: Essential ingredients in all aspects of a cells structure and function. Enzymes (help speed up reactions) Transporter proteins help transport chemicals into and out of cells. Bacteriocins kill other bacteria, certain exotoxins are proteins, some play a role in the contraction of animal muscle cells and the movement of microbial and other types of cells. Other proteins are integral parts of cell structures such as walls, cytoplasmic components, membranes, etc. Hormones are certain proteins with regulatory functions.
monomer: amino acids


Nucleic acid

Major functions: DNA, RNA were first discovered in the nuclei of cells so they are referred to as nucleic acids.
monomer: nucleotides (nitrogen containing base, pentose, and a phosphate group)are the structural units of nucleic acids.


Define Autotroph

self feeders have their own carbon source. C02



feeders on others require an organic carbon source.



An organism requiring oxygen for growth


Facultative anaerobe

An organism that can grow with or without oxygen


Obligate anaerobe

An organism that does not use oxygen and is killed in the presence of it.



An organism that grows best in an environment with less oxygen than is normally found in air



All synthesis reactions in a living organism, the building of complex organic molecules from simpler ones



All decomposition reactions in a living organism, the breakdown of complex organic compounds into simpler ones.



A decomposition reaction in which chemicals react with the H- and OH- of a water molecule.



A chemical reaction in which two or more atoms combine to form a new larger molecule



An organism that grows best at about 15 degrees C, and does not grow above 20 degrees C, a cold loving microbe.



An organism that grows between about 10 degrees C and 50 degrees C; a moderate temperature loving microbe



An organism whose optimum growth temperature is between 50 and 60 degrees C, a heat loving microbe.


Briefly describe the function of enzymes and the factors which affect the proper functioning of enzymes.

Enzymes catalyze most metabolic reactions, reducing the amount of activation energy required to start them. Factors that influence proper functioning are:
1. substrate concentration
2. Temperature
3. Enzyme inhibitors
4. pH (acidity and alkalinity)


Define co-enzyme

A non-protein substance that is associated with and that activates an enzyme


List the requirements for microbial growth

1. Temperature
2. pH
3. Osmotic Pressure
4. Chemical requirements


Describe the basic process of glycolysis and the net number of ATP's generated

A six carbon sugar is phosphorylated down into two 3-carbon compounds by use of 2 ATP. The two 3-carbon molecules are oxidized in several steps to 2 molecules of pyruvic acid, while 4 molecules of ATP are formed by substrate level phosphorylation. So net gain is 2 ATP


Compare and contrast aerobic, anaerobic respiration and fermentation.

Aerobic- 36 ATP, glycolysis, Krebs cycle, ETC, final electron acceptor is oxygen.
Anaerobic- ATP varies, only partially uses Krebs cycle, and ETC, and final electron acceptor is an inorganic molecule like nitrogen.
Fermentation- does not require Krebs cycle or ETC, uses an organic molecule as the final electron acceptor, produces small amounts like 2 ATP.


Briefly describe how ATP generates energy

ATP stores energy derived from catabolic reactions and releases it later to drive anabolic reactions and perform other cellular work. When the terminal phosphate group is split from ATP, ADP is formed and energy is released to drive anabolic reactions. ATP= ADP + P + energy, then the energy from catabolic reactions is used to combine ADP and a P to re-synthesize ATP. ADP + P + energy = ATP. Thus anabolic reactions are coupled to ATP breakdown and catabolic reactions are coupled to ATP synthesis.


Describe the differences between DNA and RNA

1. DNA is double stranded- 2 strands of alternating sugars and phosphates with nitrogen bases. RNA is single stranded.
2. DNA has thymine instead of uracil in RNA.
3. DNA has deoxyribose instead of ribose in RNA.
4. In eucaryotic cells, DNA is found throughout nucleus and in the mitochondria; RNA is in nucleolus of nucleus and in cytoplasm.


Review the 4 stages of the microbial growth curve

1. Lag phase: Period of little or no cell division. Can last for 1 hour or several days.
2. Log phase: (Exponential growth) Eventually the cell begins to divide and enter a period of growth
3. Stationary phase: Eventually the growth rate slows and the number of microbial deaths balances the number of new cells and the population stabilizes.
4. Death phase: (Logarithmic decline) Number of deaths eventually exceeds the number of new cells formed.


Define and describe phenotype, genotype

Phenotype: The actual, expressed properties, such as hair color.
Genotype: its genetic makeup, the information that codes for all the particular characteristics of the organism.


Semi-conservative replication

The original strand and a newly synthesized daughter strand, one old and one new.



DNA fragments that are strictly cytoplasmic or extra-chromosomal. Plasmids can also be transferred during conjugation. A specific example of a plasmid is the R factor plasmid. This type has genes the designate the resistance to certain antibiotics.


Define Missense, nonsense, and frame-shift mutations

Missense: A mutation that results in the substitution of an amino acid in a protein
Nonsense: A base substitution in DNA that results in a nonsense codon which does not code for any amino acid.
Frame-shift: one or a few nucleotide pairs are deleted or inserted in the DNA, makes it read wrong.


Crossing over, transformation, conjugating, and transduction

Crossing over: when 2 chromosomes exchange their DNA.
Transformation: A transfer of genes from one bacterium to another. Usually this involves a living bacterium absorbing DNA from a dead one.
Conjugation: A type of mating, resulting in the transfer of genetic material between cells.
Transduction: The transfer of genetic material from a bacterial virus (bacteriophage) into a bacterium.


fertility factor

F+ Bacteria have a fertility factor that can be transmitted to recipient cells. Donor cells are male (F+). F- bacteria lack fertility factor but can receive it from a male (F+) during conjugation.


genetic engineering

This process involves human intervention in which genes are taken from one organism and transferred into another.


Briefly summarize protein synthesis

1. Components needed to being, come together
2. tRNA is paired w/ start codon on mRNA @ P site.
3. 2nd codon moves into A site. The 2 join by peptide bone
4. Keeps moving on and 1st one reaches E site.
5. All keep bonding and start to get released
6. Ribosome moves along mRNA, new amino acids are added
7. Ribosome reaches stop codon. Polypeptide chain is released.
8. Last tRNA is released and ribosome comes apart. The released polypeptide forms a new protein.


List the body's 3 major lines of defense, describe them. Know which are nonspecific immunity and which are specific immunity.

First line of defense: nonspecific- innate immunity, skin, mucous membranes and their secretions, and normal microbiota.
Second line of defense: nonspecific- innate immunity, phagocytes, neutrophils, macrophages, etc, inflammation (swelling, pain, redness, temperature are cardinal signs of inflammation) fever, antimicrobial substances.
Third line of defense: specific- adaptive immunity, specialized lymphocytes such as T & B cells, and antibodies.


Briefly summarize the mechanism of the humoral response.

Humoral response (antibody mediated) response is carried out by antibodies produced by B cells. In humoral immunity, the bodys lymphocytes produce antibodies, which bind to antigens and label it for destruction... In a sense the body is attacking from a distance, making antibodies and sending them out...


Cell-mediated response

In Cell mediated, the cells patrol the body directly (like the police) looking for bad cells and destroy them directly... they do not produce antibodies


Name and describe the functions of the 5 types of antibodies

1. IgG- most abundant class of antibodies in serum, fix complement
2. IgM- First class of antibodies to appear after exposure to an antigen , fix complement
3. IgA- found in secretions
4. IgE- involved in hypersensitivities
5. IgD- found on B cells


Briefly describe the inflammatory response

Histamine is released from basophils. Histamine causes area blood vessels to dilate and leak out neutrophils. Fluids leak out with neutrophils causing swelling and pain as pressure build on local nerve endings. Swelling, pain, redness and area temperature are the cardinal signs of inflammation. wants to destroy pathogen, or limit ifs effects on body by walling if off, and wants to replace or repair tissue. Diapedesis- when phagocytes squeeze through cells of blood vessels to reach damaged area.


List the 3 types of complement activation

Classic pathway- c1 splits into c2a and c2b, and c4 into c4a and c4b. C2a and C4b combine and activate C3, splitting into C3a and C3b
Alternative pathway- C3 combines with factors B,D, and P on surface of microbe which causes C3 to split into fragments C3a and C3b
Lectin pathway- Lectin binds to an invading cell, once bound it splits C2 and C4, C2a and C4b combine and activate C3.


Study summary Chart

7-8 in book


General characteristics of humoral and delayed hypersensitivity reactions

Humoral- immediate, antibody mediated, involving B cells. Usually the response to the shocking dose of allergen occurs within minutes, but can occur from seconds to 24 hours in most cases, a few reactions can take several days. 3 types of immediate reactions.
1. Anaphylactic reactions- Type 1
2. Cytotoxic reactions- Type 2
3. Immune complex reactions- Type 3
Cell mediated (delayed) Type 4 involving T cells. Usually the response occurs 24-48 hours after the introduction of the shocking dose.



Transmission: Blood injection, organ transplants, sex, to babies from nursing, and while in womb
Describe progress (stages) of disease: phase 1- asymptomatic
phase 2- T cells decline to about 200, symptomatic, diarrhea, cervical cancer, etc
phase 3- AIDS, T cells below 200. infections such as C.albicans, cytomegalovirus eye infections, TB, pneumocystis.
Major precautions to prevent HIV: nonexposure, barrier protection, virucide (flushing work areas with bleach or disinfectant.), Universal standards


Define antiserum

A blood derived fluid containing antibodies


homologous antibody

Matching antibodies with antigen


Define antibody titer and describe its use

Serial dilutions (1:20, 1:40, 1:80, etc) are made with the patients serum and saline solution. The last, highest dilution that produces a visible reaction, such as agglutination or precipitation.
Usually 2 tests are run. The first at onset of symptoms (acute serum) a second test is taken after a lag period of 10-14 days after antibodies (IgM) can build up will show a rise in antibody titer (covalescent serum) indicated an active infection. The presence of antibodies but no rise between the two tests indicate a previous infection or prophylactic immunization. (IgG)


Name and describe the 8 major categories of diagnostic tests

1. Precipitation: This type of reaction involves soluble antigens combining with homologous antibodies (IgG or IgM) to form large lattices or aggregates that precipitate out of solutions. The ratio must be optimal in order for the test to work

2. Direct agglutination: These tests are very sensitive, easy to perform and read. Great variety

3. Neutralization: An antigen- antibody reaction in which the harmful effects of a bacteria exotoxin or a virus are blocked by specific antibodies.

4. Complement fixation: During most antigen-antibody reactions, complement binds to the antigen-antibody complex and is used up, or fixed, this process can be used to detect very small amounts of antibody.

5. Fluorescent Antibody: Can identify microorganisms in clinical specimens and can detect the presence of a specific antibody in serum. Combine dyes with antibodies to make them fluoresce when exposed to UV light.

6. Enzyme-Linked Immunosorbent Assay (ELISA): 2 different types. The direct detects antigens and the indirect detects antibodies. In direct testing for antigens, antibodies are absorbed into the well, sample is added, ELA is added, enzymes substrate is added, if it is positive then there will be a color change. In indirect testing for antibodies, the antigen is added to the well, and so on. Color = positive indirect test.

7. Polymerase Chain Reaction (PCR): Technique by which small samples of DNA can be quickly amplified, that is, increased to quantities that are



The degree to which a pathogen can cause disease


Herd immunity

The presence of immunity in most of a population



The cause of disease


Normal flora

Microorganisms that normally reside in and on the body and contribute to the body's function and health, normally do not cause disease.


transient flora

Present for a short period of time (days, months) but disappear or are eliminated by the body or normal microbiota


opportunistic pathogen

Normally not pathogenic as long as they remain in their normal habitat. In debilitated hosts, these pathogens man create infection or disease.



Science that studies when and where diseases occur and how they are transmitted in populations



Number of people affected by a disease in a given period of time in relation to total population



Number of deaths resulting from a disease in a population in a period of time relation to total population.


Know the classification of infectious diseases and how they can be transmitted

Definitions: Symptoms, signs, syndrome
Types of Diseases: communicable (spreads from one host to another directly or indirectly), contagious( easily spread from one person to another), noncommunicable (Not spread from one host to another).
Occurrence of Disease: sporadic, endemic, epidemic, pandemic.


Severity and duration of diseases:
acute, subacute, chronic, latent

Acute: one that develops rapidly but lasts only a short time



Intermediate between acute and chronic



Develops slowly, less severe, but likely to continue or reoccur for long periods of time



Causative agent remains inactive for a time but then becomes active to produce symptoms of disease


Extent of host involvement:
Local infection, systemic infection, focal infection, sepsis, septicemia, bacteremia, toxemia, viremia, primary infecion, secondary infection, subclinical infection, superinfection.

invading microorganisms are limited to a small area



spread throughout body



systemic infection that began in one place such as teeth, etc.


Stages of disease development
Incubation, prodromal, illness, decline, convalescence

interval between initial infection and the first appearance of any signs or symptoms.



relatively short period that follows the period of incubation in some disease



disease is most severe with most severe signs or symptoms



Signs and symptoms decline. Vulnerable to secondary infections



Regains strength and the body returns to its pre-diseased state. recovery has occurred


Review how infections and diseases spread, including nosocomial infection

Reservoirs (human, animal, nonliving), transmission (direct, indirect, droplet, vehicle such as waterborne, foodborne or airborne), vectors (mechanical such as on insects feet, or biological such as an active process). required as a result of hospital stay by direct or indirect contact.


Distinguish the major differences between exotoxins and endotoxins

Exotoxins are made in certain bacteria and secreted into the environment. Many are lethal in small amounts. Can be produced by gram (-&+), they are specific and affect certain tissues only.
Endotoxins are produced by gram - bacteria in the outer portion of their cell walls (lipid A) and are released only when bacterial cells undergo lysis, they are not specific and affect many different tissues.


List the ways microbes can penetrate host defenses

Capsules, cell wall components, enzymes, antigenic variation.


Define sterilization

The removal or destruction of all forms of microbial life



Destruction of vegetative pathogens



Removal of microbes from a limited area such as the skin around an injection site



Absence of significant contamination


List the 7 major methods of physical control and indicate which is the most effective

1. Heat disinfection (moist and dry) Dry heat such as incineration or flaming is most effective.
2. Filtration (HEPA filters, membrane filters)most do not remove viruses because they are to small
3. Refrigeration and freezing (only slows down cells)
4. Desiccation (lack of water)
5. Osmotic pressure (high concentrations of sugar or salt, therefore low water)
6. Ionizing radiation (gamma rays, x-rays, etc)
7. Non-ionizing radiation (UV)
8. Microwave


Describe the method of action and preferential uses for the following disinfectants and antiseptics:
alcohol, zinc oxide, hydrogen peroxide, chlorine, iodine, formalin, ethylene oxide gas, phenolics, glutaraldehyde.

Most effective, water is required for denaturing process, degerming, plasma membrane disruption


Zinc oxide

heavy metal- effective against diaper rash, found in mouth wash.


Hydrogen peroxide

oxidizer, degrades h2o and o that can affect anaerobes. good disinfectant, poor antiseptic



Disinfectant for treatment of drinking water and pools. oxidizer. cidal.



iodine in alcohol= tincture of iodine
oxidizer, inhibits protein function, used as antiseptic.



used in biopsy, embalming, protein denaturization


Ethylene oxide gas

sterilized materials that are damaged by heat or moisture that cannot be autoclaved, kills all microbes and endospores, requires large chambers. toxic and explosive in pure form.



Derived from coal tar, effective against mycobacterium, disinfecting pus, saliva, feces. used in Lysol.



used to disinfect respiratory equipment and embalming, cidex, protein denaturization, one of a few chemicals considered to be a sterilizing agent.


List the 5 major methods of action for antibiotics

1. Interference with Cell wall synthesis (cillins)
2. Inhibitors of protein synthesis (mycins)
3. Interference with cell membrane function (polymixin B)
4. Inhibition of Nucleic acid synthesis (Rifmapin, fluoroquinolones)
5. Interference with metabolism (sulfonamides, TMP)


Name method of action for each of the following:

Interference with cell wall systhesis


Polymixin B

Interference with cell membrane function



Inhibitor of protein synthesis



Antiviral drugs



Interference with metabolism



Antifungal drugs



Antiprotozoan drugs



Antihelminthic drugs



Inhibition of Nucleic acid synthesis


List the 4 major mechanisms that contribute to drug resistance

1. Blocking entry
2. Inactivating enzymes
3. Alteration of target molecule
4. Efflux of antibiotic