Exam 2 Flashcards
Disinfection of living tissue using a chemical agent. Safe on skin, could be alcohol, hydrogen peroxide
Antisepsis
Reduce the number of pathogens to meet public health standards
Sanitization
Use of heat to reduce the # of spoilage organisms in food or beverages
Pasteruization
3 modes of actions of microbrial control agents? How do they kill microbes?
- Alters membrane permeability
- Denatures proteins by disrupting 3d structure so that proteins cannot function
- Damages nucleic acids: DNA + RNA
Destroying microbes on inanimate objects or surfaces
Disinfecting
Killing any and all microbes
Sterilization
What is that action to bacteria and cells from radiation?
Damages nucleic acids
3 examples of using heat to denature protein + kill
- Bacticinerator
- Dry heat/hot air
- Moist heat
Examples of moist heat
Holding method (62.9 C for 30 min)
Flash method (71.6 C for 15 sec)
Ultra high temp method (140 C for 3 sec)
What type of heat is from an autoclave? 121 C at 15 lbs of pressure for 15 min
Moist heat + pressure
What are the two type of radiation?
Ionizing and non-ionizing
Examples of ionizing radiation and what it can be used on
-Gamma + X-rays
-Can preserve food
-Can be used on protein-based drugs
-Vaccines
-Plastic instruments
Examples of non-ionizing radiation and what is can be used on
-UV light (mismatch nucleotides)
-Used in OR, Morgues, and Labs
What is the action of osmosis on bacteria?
Shrivels or burst the microbe
High sure or salt water osmose OUT of the cell
What is the action of filtration on bacteria?
Pores in filter that trap microbes.
-Surgical maskm HEPA filters in heating + AC
-Some drugs get filtered
What is the action of cold on bacteria?
Slows growth, metabolism, and reproduction
Lyothalization
Removes water under a vaccum and decreases metabolism in bacteria
Action of of Phenols + Phenol derivatives
Alters membrane permeability and denatures proteins
Phenol…
Poor solubility
Is caustic to skin
Can damage CNS
Stinks
Action of aldehydes
Denatures proteins
Types of aldehydes
Formaldehyde
Formalin
Glutaraldehyde
OPA
What is the action of surfactants?
Mechanical removal of microbes
The action of hydrogren peroxide?
Free radicals -OH are toxic and damage cells by stealing electrons
Alexander Flemming
Left streak plate open + mold got into it.
Antibiotics were discovered
Define antibiotic
A substance naturally produced by a few bacterial and fungal species that inhibits or kills bacteria
Antibiotics only kill what?
Bacteria
Five target of antibiotics
- Bacterial cell wall
- Disrupting/disorganizing membranes
- Nucleic acid synthesis
- Block protein synthesis
- Metabolic pathways
What did we use before antibiotics?
Enema, blood-curdling ice baths, deadly starvation, bloodletting
Who discovered antibiotics?
Alexander Flemming
Bacterial DNA is super-coiled via an enzyme called _________
Gyrase
What is the shape of the bacterial chromosome?
Circle
How many chromosomes do bacteria usually have?
2
A plasmid carries essential information
False
Plasmids have to replicate when the bacterial chromosome replicates
False, it replicates independently
A small, circular DNA separate from the bacterial DNA is a(n)
Plasmid
The monomer of nucleic acids
Nucleotides
Nucleotides are composed of
sugar, a phosphate group, and a nitrogenous base.
The nitrogenous bases in DNA are
Adenine
Thymine
Cytosine
Guanine
How many strands does DNA contain?
2
The building block of nucleic acids is glycerol and fatty acids
False (nucleotides)
The specificity of DNA is in the
Order of the nucleotides
The building block or monomer of DNA and RNA is
Nucelotides
The sugar in DNA is
Deoxyribose
A _ is a specific sequence of nucleotides that codes for a protein or RNA
Gene
DNA is a nucleic acid
True
A _____ is the entire genetic complement of a cell or virus
Genome
The sugar in RNA is
Ribose
Nitrogenous bases in RNA are
Adenine
Uracil
Cytosine
Guanine
What are the three types of RNA?
Transfer, messenger, and ribosomal RNA
How many strands does RNA have?
1
One strand (the 5’ or five prime strand) has
A terminal phosphate group
The other strand (the 3’ or three prime strand) has a
Terminal hydroxyl group
Acts as a go between between DNA and protein
Messenger (mRNA)
Ribosomes along with proteins are what RNA is made of
Ribosomal (rRNA)
Transfers amino acids
Transfer (tRNA)
An enzyme called ________ unwinds and unzips the DNA at the ori site
Helicase
_______ adds complementary nucleoties in the 5’ > 3’ direction
DNA Polymerase
The strand that is replicated continuously is called
The leading strand
The DNA strand that’s replicated in fragments is known as
Okazaki fragments
What are Okazaki fragments knitted(seal) together by?
DNA Ligase
What direction does DNA polymerase make strands in?
5’ > 3’
The process of DNA being converted to mRNA is known as
Transcription
The process of mRNA being converted to protein is known as
Translation
moves along the DNA strand that is serving as the template and adds complementary nucleotides and builds the mRNA strand (transcription)
RNA Polymerase
Transcription occurs in ______ of prokaryotic cell
Cytoplasm
Transcription takes place in the ______ in eukaryotic cell
Nucleus
In transcription _____ is transcribed into _____
DNA, mRNA
How many DNA strands serve as a template in transcription?
1
Action of alcohol on bacteria
Damages membranes and denatures proteins
The action of gaseous sterilizer on bacteria
Denatures protein
Action of hydrogen peroxide on bacteria
Free radicals are toxic and damage cells by stealing electrons
Water disinfection
Ozone
Halogens actions on bacteria
Denatures proteins
Heavy metals on bacteria
Denatures proteins
What does drying do to bacteria?
Decreases metabolism
List what chemicals sterilize
Aldehydes, Gaseous Sterilizers, and Chlorine Dioxide by denaturing proteins
Contribution of Paul Ehrlich
Synthesized compound salvarson 606 which is an antimicrobial drug. Gave this to syphillis patients. All his compounds contained phenol and arsenic
Contribution of Gerhard Domagk
Created antimocrobial drug in form of red dye called Prontosil. Used against strep, staph, mice
Contribution of Alexander Flemming
Did research on staphylococcus and streak plate became contaminated. ID’d mold as Penicillium and tried to isolate Penicillin
Contribution of Howard Florey + Ernstchain
Chemists that isolated penicillin and was used to treat people very quickly
Contribution of Selman Waksman
Soil microbiologist that discovered 20 diff antibiotics. First to call “Antibiotics” what they’re called now
5 targets of antibiotics
- Bacterial CELL WALL
- Disrupt MEMBRANES
- NUCLEIC-ACID synthesis
- Block PROTEIN synthesis
- METABOLIC pathways
Targets of bacterias effectiveness on Gram+ and Gram -: Bacterial cell wall
Effective against GRAM +
Not effective against Gram - (outer membrane protects underlying cell wall)
Targets of bacterias effectiveness on Gram+ and Gram -: Bacterial cell wall
Effective against GRAM +
Not effective against Gram - (outer membrane protects underlying cell wall)
Targets of bacterias effectiveness on Gram+ and Gram -: Disrupts membranes
Effective against GRAM - (disrupts outer membrane)
Not effective against Gram + (thick cell wall blocks access to cell membrane)
Targets of bacterias effectiveness on Gram+ and Gram -: Nucleic-acid synthesis
Effective against both + and - gram baceria
How do bacteria resist antibiotics?
- Produce ENZYMES that destory antib.
- Decrease entry of antibiotic alter MEMBRANE PERMEABILITY
- PUMPS OUT
- Alter TARGET SITE
- Changes METABOLIC PATHWAYS
How do bacteria ACQUIRE resistance?
Mutation
Conjugation
Transduction
Transformation
The process of DNA being converted to mRNA is known as
transcription
The process of mRNA being converted to protein is known as
translation
Where does TRANSLATION occur?
Cytoplasm in both euk. and prok.
What are ribosomes?
Site of protein synthesis
Prokaryotes have what kind of ribosomes?
70s
Eukaryotes have what kind of ribosomes?
80s
Where does TRANSCRIPTION occur in prokaryotes?
Cytoplasm
Where does TRANSCRIPTION occur in eukaryotes?
Nucleus
The process of converting DNA to mRNA
Transcription
A ______ is 3 nucleotides on mRNA
Codon
Each codon specifies an
amino acid
More than one codon encodes for the same amino acid
True
The genetic code is redundant or degenerate. This means that
More than one codon encodes for the same amino acid
Can be used to cut a human gene out human DNA.
Restriction enzymes
We then insert the human gene into the plasmid and knit the DNA together using
DNA Ligase
Is used to produce human proteins including insulin, clotting factors, interferon, and growth hormone.
Recombinant DNA technology
Since the two DNA strands run __________the strands will have to be copied slightly differently.
Anti-parallel
DNA replication then proceeds _________
around the circular bacterial chromosome
Bi-laterally/directionally
Chemical and physical agents that control the growth of microorganisms that have an action of denaturing proteins include all the following EXCEPT
Radiation
Hydrogen peroxide
Cold
Drying
Osmosis
Filtration
Surfactants
Flow of information is a cell proceeds from DNA to Protein to mRNA
False
Which of the following is NOT an action of chemical or physical agents that control the growth of microorganisms?
Damage nucleic acids
Alteration of membrane permeability
Block protein synthesis
Damage nucleic acids
Block protein synthesis
Which of the following is an action of a narrow spectrum antibiotic?
inhibition of nucleic acid synthesis
Inhibition of essential metabolites
Inhibition of protein synthesis
inhibition of cell wall synthesis
inhibition of cell wall synthesis
Hydrogen peroxide is ONLY effective against obligate aerobes
False
The DNA samples are digested with a restriction enzyme this is called
RFLP or restriction fragment length polymorphism.
The DNA samples are digested with a restriction enzyme this is called
RFLP or Restriction Fragment Length Polymorphism.
Polymerase chain reaction (PCR) is used to
multiply DNA
What are the 5 targets of antibiotics?
- Protein synthesis
- Nucleic acid synthesis
- Cell wall
- Membrane
- Metabolism
4 ways antibiotics acquire resistance
Mutation
Conjugation
Transduction
Transformation
5 ways bacteria resist antibiotics
- Pump antibiotic out
- Change target site
- Produce enzymes
- Decrease entry (membrane)
- Change metabolic pathway
Contribution of Paul Ehrlich
Created Compound Salvarson 606 which was an antimicrobial drug
Created magic bullet
Contribution of Paul Ehrlich
Created Compound Salvarson 606 which was an antimicrobial drug
Created magic bullet
Contribution of Gerhard Domagk
Created a synthetic antimicrobial drug called Prontosil
Contribution of Alexander Fleming
Left streak plate + mold got into it. Mold was penicillium. Antibiotics were discovered
Contribution of Howard, Florey, and Ernst Chain
Were able to isolate penicillium
Made penicillin readily available quickly
Selman Waksman
Soil microbiologist, found 20 different antibiotics
Section of DNA that contains one or more structural genes along with a regulatory gene that controls transcription of the structural gene(s).
Operon
The ________ gene of an operon is always transcribed + translated
Regulatory Gene
The product of the regulatory gene is a
Repressor protein (can be active or inactive)
What happens when repressor protein binds to operator site?
Blocks RNA polymerase so structural genes are not transcribed and translated
Order of sections in an operon
DNA Regulatory gene [promoter, operator, structural genes]
What happens when the repressor protein binds to the operator site?
When it doesn’t bind?
Blocks RNA polymerase so structural genes are not transcribed and translated
RNA polymerase can transcribe + translate structural genes
Environmental structure is in the environment and inactivates repressor protein by attaching to it and structural genes will be made
Repressor protein is always active when structure is not in the environment
Lactose Operon “induce operon”
Environmental structure activates Repressor protein by attaching to it to block transcription and translation of structural genes
When environmental structure isn’t in the environment, Repressor protein is inactive and the structure is naturally made in our body
Tryptophan Operon
When there is no tryptophan in the environment, the repressor protein is…
Inactive so RNA polymerase can transcribe and translate the tryptophan structural gene
OPERIN IS “ON”
When there is tryptophan in the environment, the repressor protein is…
Activated by the tryptophan in the environment and stops natural transcription of tryptophan because its plentiful in environment (turkey day)
OPERON IS “OFF”
Permanent change in an organisms DNA
Mutation (1 mut per 1 bil replic.)
Permanent change in an organisms DNA
Mutation (1 mut per 1 bil replic.)
Ex of mutagens:
Exposure to UV
Xrays
Gamma rays
Benzopyrene
Mutations can be
Beneficial
Harmful
Neutral (3rd wobble)
Repair mechanism for mutation:
DNA polymerase proofreads and repairs as it copies DNA
Cancer causing agent
Carcinogen
3 Mechanics of Genetic Recombination
Transformation (recip. takes donor dna)
Transduction (bacteriophage)
Conjugation (pili sex)
Griffiths Experiment
Took 2 strains of Streptococcus pneumonia:
“S strain”: smooth, capsule caused pneumonia
“R strain”: rough, no capsule, no pathogenic
Conclusion of Griffiths experiment
Genetic recombination
Injecting heat treated “S strain” alone didnt cause pneumonia
Injecting both heat treat “S Strain” and regular “R Strain”: R strain transformed into S strain by picking up lysed S DNA
Who identified transforming factor as DNA
Avery McCloud and McCarty
Transfer and integration of DNA from lysed donor bacterium to recipient bacterium
Discovered by Frederick Griffith
Transformation
Limitations of transformation
Only competent bacteria can take up DNA (less than 1% is naturally competent )
Transfer and integration of donor bacterium via using bacteriophage
Transduction
Limitations to transduction
Bacterioaphage has to effect donor + recipient bacteria
Same genus + species
Virus + host cell specificity
In prokaryotes DNA replication occurs ________ from a single point (the origin of replication or ori site).
Bi-directionally
Bacteria are used to produce human proteins including insulin, clotting factors, interferon, and growth hormone
True
The restriction enzyme BAMHI cuts all human DNA into the same number of fragments
False
Polymerase Chain Reactino is used to multiply RNA
False (used to multiply DNA)
Bacteria is the most common vector used in gene therapy
False
In most gene therapy studies, a _______ gene is inserted into the genome to replace an ________ disease-causing gene
Normal
Abnormal
Used to determine if a chemical is a mutagen of Salmonella.
Has to do with His - and His + Salmonella
The Ames Test
Transfer and integration of donor bacterium DNA into recipient bacterium by cell-to-cell contact (sex) (pili)
Conjugation
Who discovered Transformation?
Frederick Griffith, lab studied pneumonia (R) + (S)
Who identified transforming factor as DNA
Avery McCloud + McCarty
Virus that infect bacteria
Bacteriophage
Steps in transduction:
- Phage attaches to RECEPTOR
- Phage ENTER bacteria. Donor DNA is DEGRADED
- Phage DNA uses donor cell machinery to produce PHAGE COMPONENTS
- ASSEMBLY of PROGENY PHAGE
- Donor bacterium is LYSED, and progeny phages are RELEASED + donate DONOR bacterium to the RECIPIENT. (TRANSDUCTION OCCURS)
Steps in F+ and F- Conjugation
- F+ (D) attaches to F- (R) bacterium via PILI
- ONE strand of F+ PLASMID DNA is transferred to the F- using the PILUS
- Recipient bacterium makes ONE COMPLIMENTARY F PLASMID strand to match it and now both are F+
Steps in HFR x F- Conjugation
- F+ cell’s plasmid INTEGRATES into chromosome by recombination and turns to HFR
- HFR and F- Cells join via pilus
- PORTION (1/2) of F plasmid trailing WITH CHROMOSOMAL DNA goes into recipient
- Donor chromosome+plasmid DNA is integrated into the F- chromosome but recipient bacterium is STILL F-
Are ubiquitoius and not cells
Viruses
Why are viruses not cells?
They do not fulfil the characteristics of life
How small are viruses?
Need EM to see them at 250,000x
What does it mean when we say viruses are OBLIGATE INTRACELLULAR
It means that the viruses must go inside a host cell to produce progeny like parasites
What are the viral components?
- NUCLEIC ACID (viral genome)
- CAPSID (protein coat)
- Sometimes have VIRAL ENVELOPE (animals virsues)
What viruses have a viral envelope (sometimes)?
Animal viruses
How do viruses acquire envelopes?
From host cell during viral replication
What does HELICAL shaped viruses look like?
Spiral - capsid determines shape (rabies, ebola)
What does ICOSAHEDRAL look like?
aka Polyhedral = Spherical (herpes, polio)
What do COMPLEX viruses look like?
NOT helical or icosahedral (bacteriophage, smallpox, influenza)
What are 2 ways of viral replication?
Lytic (T4 bacteriophage+ E. Coli B)
Lysogenic (Lambda + E. Coli X)
Steps in LYTIC Replication:
- ATTACHMENT: receptor specificity
- ENTRY: BYOE (lysozyme) on cell envelope, injects nucleic acid (2 strands of DNA)
- SYNTHESIS: lysozyme breaks done host DNA. uses host cell machinery
- ASSEMBLY: nucleic acid inserted in capsid to build viral progeny
- RELEASE: lysozyme comes back and lyses the cell
3 Entryways for ANIMAL Viral Replication
- Direct Penetration (some non-enveloped)
- Membrane Fusion (some enveloped)
- Endocytosis (most enveloped + some non-enveloped)
Steps in ANIMAL Viral Replication:
- Attachment: same; spikes increase attachement
- Entry: 1 of the 3 ways
- Synthesis: same; some are Retro Viruses (uses Reverse Transcriptase to turn into DNA)
- Assembly: same
- Release: Non-enveloped: progeny extruded via exocytosis > causes lysis in host
Enveloped: progeny extruded via exocytosis but take host cell membrane as their envelope > causes lysis
What do anti-viral drugs target?
ESAR
-Block ENTRY
-Block SYNTHESIS
-Prevent ASSEMBLY
-Prevent RELEASE
How do viruses + cancer contribute to each other?
Viral infection contributes to about 15-20% of all human cancers
Animal Viruses that can go latent:
HPV
Varicella-Zoster Virus (chx pox_
Herpes
Reactivation (inducing) factors in latent viruses
-Stress
-Increase in age
-Another infection
-UV light
Multiple Hit Hypothesis
-Takes multiple hits to cause cancer
-Virus = 1 hit
-Genetics, lifestyle…
How do some viruses contribute to cancer?
Virus inserts its DNA into human DNA, it then alters genes/proteins related to cell division
Gene that when activated transforms a normal cell into a cancer cell
Oncogenes
Proteinaceous infectious particle
Prion
What do prions do?
A protein that goes into your brain and unfolds proteins + refolds incorrectly
>Has a long incubation period
>Effects memory, coordination, balance
Prion brain disease:
Sponges = SPONGIFORM ENCEPHALOPATHY
Animal Prion Diseases
-Mad cow
-Chronic wasting disease (deer)
- Scrapie (sheep)
Human Prion Diseases
-CJ disease
-Kuru (ingesting dead brain)
-Fatal familial insomnia
