Principles of Disease and Epidemiology
Chapter 14
I Pathology, Infection, and Disease
A. Pathology: the scientific study of disease
1. etiology: the cause of disease
2. pathogenesis: the manner in which a disease develops
B. Infection: invasion or colonization of the body (host) by potentially pathogenic microorganisms.
C. Disease: any change from a state of health. An abnormal state in which the body is not properly adjusted or capable of performing its normal functions.
II Normal Microbiota (flora): the microorganisms that establish permanent residence (colonize) but that do not produce disease under normal conditions.
A. Protect the host by:
1. occupying niches that pathogens might occupy.
2. producing acids
3. Microbial antagonism (competitive exclusion): A phenomenon in which normal microbiota can benefit the host by preventing the overgrowth of harmful microorganisms.
a. Example: bacteriocins by E. coli dells in the large intestine, which inhibits pathogens such as Salmonella and Shigella.
b. symbiosis: the relationship between normal microbiota of a healthy person and the person.
i. commensalism: one organism benefiting, the other unaffected.
ii. mutualism: both parties benefiting
iii. parasitism: one organism benefited a the expense of the other.
B. Types:
1. gram + (aerobe)
a. Staphylococcus
b. Streptococcus
c. Candida
2. gram – (facultative anaerobe)
a. E. coli
b. Klebsiella
c. Proteus
d. Lactobacillus
e. Candida (listed under positive and negative)
C. Opportunistic Microorganisms (pathogens): They ordinarily do not cause disease in the normal habitat of a healthy person, but may do so in a different environment.
1. in the immunocompromised cell
2. as a result of a reduction in microbial microflora (as in broad spectrum antibiotics)
3. when introduced into an abnormal area of the body
4. Types:
a. E. coli.
D. Synergism: two microbes acting together have a greater effect than either acting alone.
1. probiotics: live bacterial cultures administered for beneficial effects.
2. prebiotics: chemicals administered to promote their growth.
III Etiology of Infectious Disease (did not cover this)
IV Classifying Infectious Diseases
A. Symptoms (did not cover)
B. Communicable Disease: spread directly or indirectly from one host to another.
1. contagious disease: easily spread
C. Noncommunicable diseases: not spread between hosts
D. Occurrence of a disease:
1. Endemic: disease constantly present in a population
2. Epidemic: Disease acquired by many hosts in a given area in a short time
3. Pandemic: worldwide epidemic
4. Sporadic: occurs only occasionally
E. Severity or duration (did not cover)
F. Extent of Host Involvement
1. Local infection: one in which the invading microorganisms are limited to a relatively small area of the body. (boil)
2. Systemic infection (generalized): spread throughout the body by the blood or lymphatic system.
3. Sepsis: toxic, inflammatory condition arising from the spread of bacteria or bacterial toxins from a focus of infection.
a. Septicemia: pathogens in the blood stream
i. bacteremia: bacteria pathogens in the blood
b. Toxemia: presence of toxins in the blood
V Patterns of Disease (did not cover)
VI Spread of Infection
A. Resevoirs of infection: a continual source of the pathogen
1. Human (carriers) AIDS
2. Animal (zoonoses) Rabies
3. Nonliving: soil, water. Botulism
B. Transmission of disease
1. Contact
a. direct: kissing, intercourse. Requires close association between carrier and host.
b. droplet: less than a meter (airborne)
c. indirect: involves a nonliving object such as a cup. (fomite) Syringe
2. Vehicle: inanimate reservoirs such as food, water or blood.
a. Oral-fecal
b. foodborn
c. airborne: when droplets or dust travel distance of more than a meter.
d. waterborne
3. Vectors: animals that carry pathogens from one host to another.
a. mechanical transmission: vectors carry pathogens on their bodies to food that is later swallowed by the host.
b. biological transmission: passed in a bite, or feces which later enter the wound caused by the vector.
VII Nococomial (hospital acquired) infections: one not evident or present at admission to a hospital but acquired as a result of a hospital stay.
A. 5 – 15% of all hospital patients acquire nosocomial infections.
B. Reasons:
1. Microorganisms in hospital environment
2. Compromised host
a. poor immunity
b. antibiotic resisitant drugs
3. Chain of transmission
VIII Emerging Infectious Diseases: new or changing diseases showing an increase of incidence in the recent past or a potential for increase in the near future.
A. Contributing factors:
1. evolution of new strains
2. changes in weather patterns
a. Malaria
3. Modern transportation
a. West Nile Virus
4. Ecological disaster
5. Animal control measures
a. Lyme disease
6. Public health failure
IX Epidemiology: the science that deals with the transmission of diseases in the human population, and where and when they occur. (did not cover different kinds)
Friday, April 11, 2008
Chapter 8 Microbial Genetics
Microbial Genetics Chapter 8
I Structure and function of genetic material
A. DNA is composed of repeating nucleotides
1. Base pairs (the hydrogen bonds from which DNA is connected)
a. Adenine & Thymine
b. Cystosine & Guanine
2. Deoxyribose sugar & Phosphate group
a. The “backbone” or basis of DNA is deoxyribose.
b. Phosphate is held together by hydrogen bonds between AT & CG.
II DNA replication (Reproduction)
(see next page for steps)
A. Bacteria replication begins at the origin of replication.
B. Circular molecule
C. DNA polymerase
III RNA and Protein Synthesis (Regulation)
A. Transcription: a strand of mRNA is synthesized from the genetic info of DNA.
1. Uracil replaces Thymine. (AT becomes AU)
2. promoter site: the region where RNA polymerase binds to DNA and transcription begins.
3. terminator site: where RNA polymerase and newly formed mRNA are released from the DNA, signaling the end point for transcription of the gene.
B. Translation: translates the language of nucleic acids into the language of proteins.
1. codons: (the language of mRNA) groups of 3 nucleotides that “code” for a particular amino acid.
a. 64 possible codons
b. 20 amino acids (therefore amino acids have more than one codon)
c. degeneracy of the code: 20 amino acids/64 codons
d. sense codons: code for amino acids
e. nonsense codons: signal the end of the synthesis of protein.
i. UAA, UGA, UAG
f. Met/start codon
i. AUG
2. Ribosomes: the sites of translation that move along mRNA.
a. Transfer (t)RNA: transports amino acids to the ribosome.
b. anticodon: a complimentary tRNA molecule made for a specific amino acid. (3 nucleotides by which a tRNA recognizes an mRNA codon.) AUG for mRNA meets UAC for tRNA.
IV Mutations: a change in the base sequence (genetic material) of DNA. Carcinogenic and can be genetic.
A. Types
1. base substitution
2. nonsense mutation
3. Spontaneous: occurs without known intervention of mutation causing agents.
B. Mutagens: chemicals and radiation that bring about mutations.
1. Chemical mutagens
2. Radiation
a. ionizing
b. nonionizing
i. UV light
3. Viruses
V Genetic transfer and recombination
A. Recombination, general overview:
1. Donor cell gives a portion of its total DNA to a different recipient cell.
2. Recipient cell (aka recombinant) DNA from donor is added to its own DNA.
3. Vertical gene transfer: DNA passed from an organism to its offspring.
4. horizontal gene transfer: DNA passed laterally to other microbes of the same generation.
B. Recombination: the rearrangement of genes to form new combinations. Types:
1. Transformation
a. DNA released when donor cell dies.
b. DNA taken up by adjacent cells.
c. competence: the ability to take up foreign DNA.
i. ex: antibiotic resistance
d. Gram + that can take up outside DNA (exogenous)
i. Streptococcus pneumoniae
ii. Staphylococcus aureus
iii. Bacillus subtilis
e. Gram – (neg) that can take up exogenous DNA
i. Neisseria meningitis
ii. Neisseria gonorrhea
iii. Haemophilus influenzae
iv. E. coli
2. Conjugation: transfer of a plasmid (F- Factor) DNA from one bacterium to another. (page 243)
a. Plasmid transfer in gram – bacteria occurs only between strains of the same species or closely related species.
b. Need cell to cell contact. With a sex pilus. (This is how we get a double coil plasmid.)
c. Usually only occurs in gram – bacteria. The exceptions are gram +:
i. Bacillus subtilis
ii. some Streptococcus
iii. Enterococcus faecalis
3. Transduction: A virus carries DNA from one bacteria to another.
(pg 244)
a. Generalized, not specific.
b. Occurs between unrelated species.
c. Can often lead to changes in microbial pathogenicity.
i. Botulism toxin of Clostridium botulinum
ii. Capsule of Streptococcus pneumoniae
iii. E. coli 0157.H7 toxin. (pathogenic)
VI Plasmids and transposons (only went over plasmids)
A. Plasmids: circular pieces of DNA that replicate independently from the cell’s chromosome.
1. Plasmids usually carry only genes that are not essential for growth of the cell.
2. Types
a. dissimilation plasmids: code for enzymes to utilize unusual sugars and hydrocarbons. (Pseudomonas)
b. bacteriocins: toxic proteins that kill other bacteria.
i. plasmids cause the synthesis of bacteriocins
c. resistance (R)factors: carry genes for antibiotic resistance and other antimicrobial factors.
i. encode antibiotic resistance in gram negative bacteria.
d. other plasmids contribute to the pathogenicity of microbes.
i. S. mutans, the cause of cavities.
I Structure and function of genetic material
A. DNA is composed of repeating nucleotides
1. Base pairs (the hydrogen bonds from which DNA is connected)
a. Adenine & Thymine
b. Cystosine & Guanine
2. Deoxyribose sugar & Phosphate group
a. The “backbone” or basis of DNA is deoxyribose.
b. Phosphate is held together by hydrogen bonds between AT & CG.
II DNA replication (Reproduction)
(see next page for steps)
A. Bacteria replication begins at the origin of replication.
B. Circular molecule
C. DNA polymerase
III RNA and Protein Synthesis (Regulation)
A. Transcription: a strand of mRNA is synthesized from the genetic info of DNA.
1. Uracil replaces Thymine. (AT becomes AU)
2. promoter site: the region where RNA polymerase binds to DNA and transcription begins.
3. terminator site: where RNA polymerase and newly formed mRNA are released from the DNA, signaling the end point for transcription of the gene.
B. Translation: translates the language of nucleic acids into the language of proteins.
1. codons: (the language of mRNA) groups of 3 nucleotides that “code” for a particular amino acid.
a. 64 possible codons
b. 20 amino acids (therefore amino acids have more than one codon)
c. degeneracy of the code: 20 amino acids/64 codons
d. sense codons: code for amino acids
e. nonsense codons: signal the end of the synthesis of protein.
i. UAA, UGA, UAG
f. Met/start codon
i. AUG
2. Ribosomes: the sites of translation that move along mRNA.
a. Transfer (t)RNA: transports amino acids to the ribosome.
b. anticodon: a complimentary tRNA molecule made for a specific amino acid. (3 nucleotides by which a tRNA recognizes an mRNA codon.) AUG for mRNA meets UAC for tRNA.
IV Mutations: a change in the base sequence (genetic material) of DNA. Carcinogenic and can be genetic.
A. Types
1. base substitution
2. nonsense mutation
3. Spontaneous: occurs without known intervention of mutation causing agents.
B. Mutagens: chemicals and radiation that bring about mutations.
1. Chemical mutagens
2. Radiation
a. ionizing
b. nonionizing
i. UV light
3. Viruses
V Genetic transfer and recombination
A. Recombination, general overview:
1. Donor cell gives a portion of its total DNA to a different recipient cell.
2. Recipient cell (aka recombinant) DNA from donor is added to its own DNA.
3. Vertical gene transfer: DNA passed from an organism to its offspring.
4. horizontal gene transfer: DNA passed laterally to other microbes of the same generation.
B. Recombination: the rearrangement of genes to form new combinations. Types:
1. Transformation
a. DNA released when donor cell dies.
b. DNA taken up by adjacent cells.
c. competence: the ability to take up foreign DNA.
i. ex: antibiotic resistance
d. Gram + that can take up outside DNA (exogenous)
i. Streptococcus pneumoniae
ii. Staphylococcus aureus
iii. Bacillus subtilis
e. Gram – (neg) that can take up exogenous DNA
i. Neisseria meningitis
ii. Neisseria gonorrhea
iii. Haemophilus influenzae
iv. E. coli
2. Conjugation: transfer of a plasmid (F- Factor) DNA from one bacterium to another. (page 243)
a. Plasmid transfer in gram – bacteria occurs only between strains of the same species or closely related species.
b. Need cell to cell contact. With a sex pilus. (This is how we get a double coil plasmid.)
c. Usually only occurs in gram – bacteria. The exceptions are gram +:
i. Bacillus subtilis
ii. some Streptococcus
iii. Enterococcus faecalis
3. Transduction: A virus carries DNA from one bacteria to another.
(pg 244)
a. Generalized, not specific.
b. Occurs between unrelated species.
c. Can often lead to changes in microbial pathogenicity.
i. Botulism toxin of Clostridium botulinum
ii. Capsule of Streptococcus pneumoniae
iii. E. coli 0157.H7 toxin. (pathogenic)
VI Plasmids and transposons (only went over plasmids)
A. Plasmids: circular pieces of DNA that replicate independently from the cell’s chromosome.
1. Plasmids usually carry only genes that are not essential for growth of the cell.
2. Types
a. dissimilation plasmids: code for enzymes to utilize unusual sugars and hydrocarbons. (Pseudomonas)
b. bacteriocins: toxic proteins that kill other bacteria.
i. plasmids cause the synthesis of bacteriocins
c. resistance (R)factors: carry genes for antibiotic resistance and other antimicrobial factors.
i. encode antibiotic resistance in gram negative bacteria.
d. other plasmids contribute to the pathogenicity of microbes.
i. S. mutans, the cause of cavities.
Chapter 8 DNA Replication
DNA Replication
1. Two helical strands unravel and separate from each other at a replication fork.
2. Synthesis of new strand begins.
3. Complementary base pairing yields a complementary copy of the original DNA. (AT, CG)
4. Segments of new nucleotides are joined to form short strands of DNA by DNA polymerase enzymes.
5. Short strands are joined into continuous DNA by action of DNA ligase enzymes.
(skipped some enzyme steps here)
6. Called semi conservative replication because each new double stranded DNA molecule has one original strand and one new strand.
Protein Synthesis
1. DNA gets a signal we need more proteins. Sends a message to mRNA.
2. mRNA carries the message DNA to protein transcriber.
1. mRNA is translated in codons. (three mRNA nucleotides = one amino acid)
2. codons “encode” for each amino acid in a protein (see degeneracy, sense, nonsense)
3. codes until it gets a stop codon because there is no tRNA to stop it. Has a start and an end because they don’t want the entire DNA transcribed.
DNA Polymerase reads it in:
E: placing (empty site)
P: reading (where the peptide bond happens. Peptide bond joins two amino acids)
A: attachment
(another way to look at it)
Transcription: In transcription, a strand of messenger RNA (mRNA) is synthesized from the genetic information in DNA. The region where RNA polymerase (needed for synthesis) binds to DNA and transcription begins is known as the promoter site. The terminator site is whereENA polymerase and newly formed mRNA are released from the DNA, signaling the endpoint for transcription of the gene.
Translation: Protein synthesis is called translation because it translates the language of nucleic acids into the language of proteins. The language of mRNA is in codons, groups of three nucleotides such as AUG. Each codon “codes” for a particular amino acid. The sites of translation are ribosomes that move along mRNA. The amino acids are transported to the ribosome by transfer RNA (tRNA). Each tRNA molecule is made specifice for an amino acid by an anticodon that is complementary to a codon. The codon AUG would be complementary to the anticodon UAC. (see 8.9 fig)
Various facts
mRNA is the transcriber
rRNA on ribosomes
tRNA translator
RNA polymerase is in transcription.
The “ladder” sides of DNA are made up of phosphate and carbon.
Most bacteria have only one chromosome.
Circular molecule
DNA polymerase: enzyme that replicates DNA
There are two major steps for expressing any enzyme:
1. transcription
2. translation
Proteins are composed of amino acids. (GCAT)
DNA is made up of nucleotides
Reproduction = DNA replication
Regulation = protein synthesis
Ribosome carry out protein synthesis. 50s and 30s = 70s
Protein synthesis starts at AUG.
AUG may be the start of a new amino acid or the middle of another.
Protein synthesis ends at UAA, UAG, UGA. (nonsense codons)
You do not need a live cell for recombination, only a piece of DNA is transferred. Host may take 2 genes and leave 8. The rest will degrade. That is why it is so scary, bacteria dies, but the DNA lives. (I think in this case she was talking about TRANSFORMATION)
Definitions
RNA primer: a short strand of RNA used to start synthesis of the lagging strand of DNA, and to start the polymerase chain reaction.
mRNA: (messenger RNA) the type of RNA molecule that directs the incorporation of amino acids into proteins.
tRNA: (transfer RNA) the type of RNA molecule that brings amino acid to the ribosomal site where they are incorporated into proteins.
Anticodon: the three nucleotides by which a tRNA recognizes an mRNA codon.
Bacteriocin: An antimicrobial peptide produced by bacteria that kills other bacteria.
Chromosomes: The structure that carries hereditary information; chromosomes contain genes.
Codon: a sequence of three nucleotides in mRNA that specifies the insertion of an amino acid into a polypeptide.
Degeneracy: Redundancy of the genetic code; that is, most of the amino acids are encoded by several codons.
Genetic code: the mRNA codons and the amino acids they encode.
Genetic recombination: the process of joining pieces of DNA from different sources.
Genome: One complete copy of the genetic information in a cell.
Genotype: The genetic makeup of an organism.
Lagging strand: During DNA replication, the daughter strand that is synthesized discontinuously.
Leading strand: During DNA replication, the daughter strand that is synthesized continuously.
Nonsense codon: a condon that does not encode any amino acid.
Phenotype: the external manifestations of an organism’s genotype (genetic makeup)
Replication fork: The point where DNA strands separate and new strands will be synthesized.
Semiconservative replication: The process of DNA replication in which each double-stranded DNA molecule contains one original strand and one new one.
Spontaneous mutation: a mutation that occurs without a mutagen.
Transcription: The process of synthesizing RNA from a DNA template.
Translation: the mRNA as a template in the synthesis of protein.
1. Two helical strands unravel and separate from each other at a replication fork.
2. Synthesis of new strand begins.
3. Complementary base pairing yields a complementary copy of the original DNA. (AT, CG)
4. Segments of new nucleotides are joined to form short strands of DNA by DNA polymerase enzymes.
5. Short strands are joined into continuous DNA by action of DNA ligase enzymes.
(skipped some enzyme steps here)
6. Called semi conservative replication because each new double stranded DNA molecule has one original strand and one new strand.
Protein Synthesis
1. DNA gets a signal we need more proteins. Sends a message to mRNA.
2. mRNA carries the message DNA to protein transcriber.
1. mRNA is translated in codons. (three mRNA nucleotides = one amino acid)
2. codons “encode” for each amino acid in a protein (see degeneracy, sense, nonsense)
3. codes until it gets a stop codon because there is no tRNA to stop it. Has a start and an end because they don’t want the entire DNA transcribed.
DNA Polymerase reads it in:
E: placing (empty site)
P: reading (where the peptide bond happens. Peptide bond joins two amino acids)
A: attachment
(another way to look at it)
Transcription: In transcription, a strand of messenger RNA (mRNA) is synthesized from the genetic information in DNA. The region where RNA polymerase (needed for synthesis) binds to DNA and transcription begins is known as the promoter site. The terminator site is whereENA polymerase and newly formed mRNA are released from the DNA, signaling the endpoint for transcription of the gene.
Translation: Protein synthesis is called translation because it translates the language of nucleic acids into the language of proteins. The language of mRNA is in codons, groups of three nucleotides such as AUG. Each codon “codes” for a particular amino acid. The sites of translation are ribosomes that move along mRNA. The amino acids are transported to the ribosome by transfer RNA (tRNA). Each tRNA molecule is made specifice for an amino acid by an anticodon that is complementary to a codon. The codon AUG would be complementary to the anticodon UAC. (see 8.9 fig)
Various facts
mRNA is the transcriber
rRNA on ribosomes
tRNA translator
RNA polymerase is in transcription.
The “ladder” sides of DNA are made up of phosphate and carbon.
Most bacteria have only one chromosome.
Circular molecule
DNA polymerase: enzyme that replicates DNA
There are two major steps for expressing any enzyme:
1. transcription
2. translation
Proteins are composed of amino acids. (GCAT)
DNA is made up of nucleotides
Reproduction = DNA replication
Regulation = protein synthesis
Ribosome carry out protein synthesis. 50s and 30s = 70s
Protein synthesis starts at AUG.
AUG may be the start of a new amino acid or the middle of another.
Protein synthesis ends at UAA, UAG, UGA. (nonsense codons)
You do not need a live cell for recombination, only a piece of DNA is transferred. Host may take 2 genes and leave 8. The rest will degrade. That is why it is so scary, bacteria dies, but the DNA lives. (I think in this case she was talking about TRANSFORMATION)
Definitions
RNA primer: a short strand of RNA used to start synthesis of the lagging strand of DNA, and to start the polymerase chain reaction.
mRNA: (messenger RNA) the type of RNA molecule that directs the incorporation of amino acids into proteins.
tRNA: (transfer RNA) the type of RNA molecule that brings amino acid to the ribosomal site where they are incorporated into proteins.
Anticodon: the three nucleotides by which a tRNA recognizes an mRNA codon.
Bacteriocin: An antimicrobial peptide produced by bacteria that kills other bacteria.
Chromosomes: The structure that carries hereditary information; chromosomes contain genes.
Codon: a sequence of three nucleotides in mRNA that specifies the insertion of an amino acid into a polypeptide.
Degeneracy: Redundancy of the genetic code; that is, most of the amino acids are encoded by several codons.
Genetic code: the mRNA codons and the amino acids they encode.
Genetic recombination: the process of joining pieces of DNA from different sources.
Genome: One complete copy of the genetic information in a cell.
Genotype: The genetic makeup of an organism.
Lagging strand: During DNA replication, the daughter strand that is synthesized discontinuously.
Leading strand: During DNA replication, the daughter strand that is synthesized continuously.
Nonsense codon: a condon that does not encode any amino acid.
Phenotype: the external manifestations of an organism’s genotype (genetic makeup)
Replication fork: The point where DNA strands separate and new strands will be synthesized.
Semiconservative replication: The process of DNA replication in which each double-stranded DNA molecule contains one original strand and one new one.
Spontaneous mutation: a mutation that occurs without a mutagen.
Transcription: The process of synthesizing RNA from a DNA template.
Translation: the mRNA as a template in the synthesis of protein.
Microbial Control Chpt 7 Physical Methods
Microbial Control Chapter 7
Physical Methods
I Disinfection: for inanimate objects. Reduces the amount of bacteria. (decreases, not eliminate)
II Sterilization: for animate objects. Kills all cells.
A. cidal: kills bacteria and endospores
B. static: upon usage killed, but when removed they regrow. (refrigeration)
C. order of death:
1. gram +
2. lipid virus
3. gram –
4. endospore
III Heat: structural proteins and enzymes damaged (denatured). Water is lost.
A. Dry heat: kills all forms of life.
1. hot air: 2 hours at 170 C. (baking) requires a long time.
2. direct flame/incineration
B. Moist heat
1. boiling: 10 minutes at 100 C. Used for food and water.
a. Will not kill Clostridium.
b. Kills 95% of bacteria.
c. for disinfection of food and water.
2. autoclaving: 15psi @ 121 C for 20 minutes.
a. kills all organisms and spores
b. widely used in medical applications.
3. Pasteurization: 15 seconds @ 72 C
a. milder process
b. makes materials (wine, milk) safe
c. aka: intermediated (intermittent) heating
4. UHT (ultra high temperature) 5 seconds @ 140 C
a. short time at high temp
b. “flash” sterilization
c. Ex: start at 74 C, heat at 5 seconds @ 140 C, back to 74 C.
IV Filtration
A. Membrane filters for fluids
B. HEPA filters for air
V Radiation
A. Ionizing radiation (x-ray, gamma ray)
1. highly penetrating
2. generate free radicals inside cells
3. used for certain medical products
4. use on food being explored. (don’t want humans creating free radicals)
B. Non-ionizing radiation (UV)
1. damages DNA
2. poor penetration
3. used primarily for surface sterilization (germicidal lamps)
VI Drying: creates a hypertonic situation
A. Salting
B. Sugaring
VII Low Temperature
A. Refrigeration is bacteriostatic
************************************************************************
Various notes
Microwaving does not kill endospores
Antibiotics are ingested to kill bacteria.
Clostridium = endospores
Order of death:
1. gram +
2. lipid virus (b/c easily soluble in disinfectant)
3. gram - (b/c of polylipid layer)
4. endospore
Physical Methods
I Disinfection: for inanimate objects. Reduces the amount of bacteria. (decreases, not eliminate)
II Sterilization: for animate objects. Kills all cells.
A. cidal: kills bacteria and endospores
B. static: upon usage killed, but when removed they regrow. (refrigeration)
C. order of death:
1. gram +
2. lipid virus
3. gram –
4. endospore
III Heat: structural proteins and enzymes damaged (denatured). Water is lost.
A. Dry heat: kills all forms of life.
1. hot air: 2 hours at 170 C. (baking) requires a long time.
2. direct flame/incineration
B. Moist heat
1. boiling: 10 minutes at 100 C. Used for food and water.
a. Will not kill Clostridium.
b. Kills 95% of bacteria.
c. for disinfection of food and water.
2. autoclaving: 15psi @ 121 C for 20 minutes.
a. kills all organisms and spores
b. widely used in medical applications.
3. Pasteurization: 15 seconds @ 72 C
a. milder process
b. makes materials (wine, milk) safe
c. aka: intermediated (intermittent) heating
4. UHT (ultra high temperature) 5 seconds @ 140 C
a. short time at high temp
b. “flash” sterilization
c. Ex: start at 74 C, heat at 5 seconds @ 140 C, back to 74 C.
IV Filtration
A. Membrane filters for fluids
B. HEPA filters for air
V Radiation
A. Ionizing radiation (x-ray, gamma ray)
1. highly penetrating
2. generate free radicals inside cells
3. used for certain medical products
4. use on food being explored. (don’t want humans creating free radicals)
B. Non-ionizing radiation (UV)
1. damages DNA
2. poor penetration
3. used primarily for surface sterilization (germicidal lamps)
VI Drying: creates a hypertonic situation
A. Salting
B. Sugaring
VII Low Temperature
A. Refrigeration is bacteriostatic
************************************************************************
Various notes
Microwaving does not kill endospores
Antibiotics are ingested to kill bacteria.
Clostridium = endospores
Order of death:
1. gram +
2. lipid virus (b/c easily soluble in disinfectant)
3. gram - (b/c of polylipid layer)
4. endospore
Chapter 7 Microbial Control Chemical Methods
Microbial Control Chapter 7
Chemical Methods
Fall into two categories:
Antiseptics: reduce the number of microbes and viruses on living tissue
Disinfectants: destruction of most microorganisms and viruses on non-living tissue
I Alcohol
A. Isopropanol (rubbing alcohol) 70%
B. Ethanol 90% alcohol
C. denatures proteins and disrupt cell membranes
D. Kills most microbes (not spores)
E. Used as antiseptic or disinfectant
II Chlorine: denatures proteins
A. Hypochlorite (Bleach)
B. Chloramine (Cl & NH3)
C. Gas
D. Widely used as disinfectant, antiseptic, and water purification
III Phenols: denatures proteins and disrupts cell membranes
A. Examples: Lysol, hibiclens, phisohex, triclosan
B. Widely used as skin antiseptic and disinfectant, but harsh on skin
IV Iodine: denatures proteins
A. tincture (mixed with alcohol)
B. iodophors (betadine)
C. widely used as a skin antiseptic
V QUATS (quanternary ammonium compound): disrupt cell membranes
A. surface active chemicals (surfactants)
B. detergents: zepharin & cepacol
C. Antiseptic: mill many microbes, but spores and others are resistant.
D. works effectively against gram + bacteria
VI Hydrogen Peroxide: denatures proteins
A. used as antiseptic or disinfectant for deep wounds
B. a catalyst enzyme (by product of aerobic respiration….oxidation)
VII Formaldehyde & Gluteraldehyde: denatures proteins and inactivating nucleic acids
A. kills all microbes and spores
B. toxic and irritating
C. used as preservative and for vaccine production
VIII Ethylene Oxide: denatures proteins
A. gas
B. kills all microbes and spores
C. Sterilization of heat and water-sensitive objects
D. widely used on medical supplies and equipment
E. may be carcinogenic
Chemical Methods
Fall into two categories:
Antiseptics: reduce the number of microbes and viruses on living tissue
Disinfectants: destruction of most microorganisms and viruses on non-living tissue
I Alcohol
A. Isopropanol (rubbing alcohol) 70%
B. Ethanol 90% alcohol
C. denatures proteins and disrupt cell membranes
D. Kills most microbes (not spores)
E. Used as antiseptic or disinfectant
II Chlorine: denatures proteins
A. Hypochlorite (Bleach)
B. Chloramine (Cl & NH3)
C. Gas
D. Widely used as disinfectant, antiseptic, and water purification
III Phenols: denatures proteins and disrupts cell membranes
A. Examples: Lysol, hibiclens, phisohex, triclosan
B. Widely used as skin antiseptic and disinfectant, but harsh on skin
IV Iodine: denatures proteins
A. tincture (mixed with alcohol)
B. iodophors (betadine)
C. widely used as a skin antiseptic
V QUATS (quanternary ammonium compound): disrupt cell membranes
A. surface active chemicals (surfactants)
B. detergents: zepharin & cepacol
C. Antiseptic: mill many microbes, but spores and others are resistant.
D. works effectively against gram + bacteria
VI Hydrogen Peroxide: denatures proteins
A. used as antiseptic or disinfectant for deep wounds
B. a catalyst enzyme (by product of aerobic respiration….oxidation)
VII Formaldehyde & Gluteraldehyde: denatures proteins and inactivating nucleic acids
A. kills all microbes and spores
B. toxic and irritating
C. used as preservative and for vaccine production
VIII Ethylene Oxide: denatures proteins
A. gas
B. kills all microbes and spores
C. Sterilization of heat and water-sensitive objects
D. widely used on medical supplies and equipment
E. may be carcinogenic
Glycolosis Preparatory Stage
Glycolysis Preparatory Stage
In this stage, 2 molecules of atp are used to phosphorylate a molecule of glucose. The resultant phosphorylated sugar is then split into two 3-carbon molecules.
Glucose enters the cell and is phosphorylated 000000
A molecule of atp is invested ATP
The product is glucose 6 phosphate 000000p
Enzyme
000000p (fructose 6)
ATP
p000000p (1,6 diphosphate)
enzyme
p000 000p
Next an enzyme rearranges glucose 6 phosphate to create fructose 6 phosphate
The phosphate from another atp is used to produce fructose 1,6 diphosphate
Note that 2 atp molecules have been invested up to this point
Next an enzyme splits the sugar into 2 three carbon molecules and the preparatory stage of glycolysis is completed.
2 molecules of ATP used so far. Created two 3 carbon units.
In this stage, 2 molecules of atp are used to phosphorylate a molecule of glucose. The resultant phosphorylated sugar is then split into two 3-carbon molecules.
Glucose enters the cell and is phosphorylated 000000
A molecule of atp is invested ATP
The product is glucose 6 phosphate 000000p
Enzyme
000000p (fructose 6)
ATP
p000000p (1,6 diphosphate)
enzyme
p000 000p
Next an enzyme rearranges glucose 6 phosphate to create fructose 6 phosphate
The phosphate from another atp is used to produce fructose 1,6 diphosphate
Note that 2 atp molecules have been invested up to this point
Next an enzyme splits the sugar into 2 three carbon molecules and the preparatory stage of glycolysis is completed.
2 molecules of ATP used so far. Created two 3 carbon units.
Exam 2 Various Notes
Exam 2
Various Notes
44 multiple choice
6 fill in the blanks/short answer. May be write the difference between 2 cycles, or describe a cycle.
Chapter 5
115
119
121-125
125-131
133-136
137-143
Chapter 6
Complete chapter
161-163 carbon and nitrogen
Know range, mesophiles etc
166 not enzymes
Know pic @ top and definition
167 not mechanisms
168 chemic def media
Fastidious
Complex
Omit anaerobic growth media and methods
171 selective and differential media
172, not 17
Chapter 13
387-393
400-410
411-412: latent and persistent viral infections
Various Notes
44 multiple choice
6 fill in the blanks/short answer. May be write the difference between 2 cycles, or describe a cycle.
Chapter 5
115
119
121-125
125-131
133-136
137-143
Chapter 6
Complete chapter
161-163 carbon and nitrogen
Know range, mesophiles etc
166 not enzymes
Know pic @ top and definition
167 not mechanisms
168 chemic def media
Fastidious
Complex
Omit anaerobic growth media and methods
171 selective and differential media
172, not 17
Chapter 13
387-393
400-410
411-412: latent and persistent viral infections
Subscribe to:
Posts (Atom)