Final Flashcards
What is the Normal Flora?
microbes that are normally resident in/on the human body
*bacteria and fungi predominate
What are the properties of antigens?
non-self
foreign
makes Igs vs them
B and T cells recognize them
What do antigens cause?
activates immune response
What types of molecules are antigens?
polypeptides (STRONGEST) T cells can respond to them when presented to MHC 1 proteins, some carbs can be (O antigen), some nucleic acids
What cell(s) stimulate a T helper cell?
threshold # of antigen has to be presented
T cell receptor has to bind to presented antigen
CD4 binds to macrophage
What cell(s) stimulate a B cell?
an activated Th cell that has been activated by an APC
What cell(s) stimulate a Cytotoxic T cell?
viral infected cells, cancer cells, and cells from other animals and humans
What are the Basic Immune Functions?
Innate (Non-specific) and Adaptive Defenses (Specific)
What is the 1st Line of your Immune Defense?
Non-Specific/Innate BARRIERS
-skin
-secretions
-bacteria
ALL ON SURFACE AND MUCUS
What is the 2nd Line of your Immune Defense?
Non-Specific/Innate RESPONSES
-phagocytic cells
-Inflammation
-Fever
-Proteins: interferon, complement
What is the 3rd Line of your Immune Defense?
Specific/Adaptive RESPONSES vs ANTIGENS
-Cell-Mediated response (T cells secrete cytokines or cytotoxins)
-Humoral response (B cells make antibodies
What is a Prokaryote Cell Structure?
-Have DNA
-Have a Plamsa Membrane
-Have Cytoplasm
-unicellular
-Domains= bacteria, archaea
What is a Eukaryote Structure?
-Have DNA
-Have a Plasma Membrane
-Have Cytoplasm
-unicellular/multicellular
-Domain= eukarya
What organisms are an example of a prokaryote?
bacteria and archaea (domain)
What organisms are an example of a eukaryote?
-Fungi
-Yeasts (single celled)
-Molds (multicellular)
-Protozoa (single celled)
-Helminths (worms)
What are cell walls?
-membrane support
-resistance to osmotic pressure
-gives cell shape
What is the composition of a cell wall?
gram + = peptidoglycan and cell membrane
gram - = outer membrane, peptidoglycan and cell membrane
What organisms have mycolic acid in the cell wall?
mycobacterium
What organism(s) reproduce asexually by binary fission?
E. coli, protozoa, bacteria, eukaryotes
What organism(s) reproduce sexually?
protozoa, eukaryotes
How do Fungi harm host tissues?
harm by digesting your tissue
What is protozoa?
microbes that are too large to be phagocytized
-eukaryotic cell type
-unicellular
-no cell wall
-classified by type of movement
-does not secrete toxins
-does both asexual and sexual reproduction
-can produce cysts
-chemoheterotrophs
How does protozoa harm host tissues?
cause excessive diarrhea and cause you to become dehydrated and you die
What is MIC?
Minimum Inhibitory Concentration
-useful in determining the smallest effective dosage of a drug and in providing a comparative index against other antimicrobials
What is MBC?
Minimum Bacteria Concentration- MBC is MIC if cidal
How are heat labile solutions treated?
autoclave
gaseous sterilants- ethylene oxide
Why are heat labile solutions treated the way that they are?
proteins are denatured and nucleotides are inactivated
What is the treatment for steel/surgical tools? Why?
disinfection or autoclave
What is the treatment for solutions? Why?
filtration
What is the treatment for heat labile plastic devices? Why?
radiation, you can’t autoclave because the plastic will melt
What is the fermentation pathway?
-anaerobic (doesn’t require oxygen)
-consists of glycolysis and fermentation
-2 net ATP
-makes pyruvate
-makes reduced electron carrier and recycles it in fermentation step and converts it into an acid or alcohol
How does the fermentation pathway work?
glucose -> pyruvate -> organic acid/alcohol
(Glycolysis is the first step, fermentation is the second)
What step of the growth curve are microbes most susceptible to treatment?
log phase- most rapidly metabolizing and take the drug more effectively
How are surgical tools sterilized?
disinfection, autoclave (can do anything really)
How are heat labile IV solutions sterilized?
gaseous- ethylene oxide
How are plastic IV line fittings sterilized?
radiation and gaseous sertilants
What is the central dogma of biology?
DNA to RNA to Protein
What is gene expression?
the process by which a gene gets turned on in a cell to make RNA and proteins
How is gene expression regulated?
Prokaryotes: in transcription
Eukaryotes: in transcription and translation
What is the genetic code?
the relationship between mRNA codons and amino acids
What is spontaneous mutation? (How do they happen and what is their outcome?)
involve…
replication
randomly
rare
What is a point mutation? (How do they happen and what is their outcome?)
-One DNA base is substituted for another
-1 codon is affected
What is a silent mutation? (How do they happen and what is their outcome?)
-same/similar amino acid
-no phenotype change
What is a missense mutation? (How do they happen and what is their outcome?)
-different amino acid
-altered phenotype
*DON’T affect overall shape and function of the protein
What is a nonsense mutation? (How do they happen and what is their outcome?)
-premature stop codons
-non functional protein (a protein that terminates or ends its translation earlier than expected)
What is a frameshift mutation? (How do they happen and what is their outcome?)
-DNA bases are removed/added that are not in multiples of 3, which disrupts the triplet reading of a DNA sequence
-Outcomes: codon reading frame is thrown off & non-functional proteins usually result (MORE THAN ONE CODON AFFECTED)
What are insertions? (How do they happen and what is their outcome?)
Involves the addition of one or more nucleotide base pairs into a segment of DNA
-Occurs from an error during DNA replication
-Can either result in no change OR can lead to a pathogenic variant associated with a genetic disease
What are deletions? (How do they happen and what is their outcome?)
-Occurs when part of the DNA is not copied during replication
-Involves the loss of any number of nucleotides
-cause for many genetic diseases such as cystic fibrosis
What are the 4 targets for antibiotic therapy?
- cell wall: peptidoglycan, chitin (in fungi) LEAST SIDE EFFECTS
-protein synthesis (70s Ribosome complex)
-nucleic acid: DNA/RNA synthesis
-cell membrane: structure, ergosterol (in fungi) GREATEST SIDE EFFECTS=
What are the 4 ways that microbes become antibiotic resistant
-Inactivation of the drug by enzymes
-Alteration or loss of drug target
-Decreased entry of drug into cell (altered membrane transport)
-Rapid efflux of the drug
*Drug resistance can also be due to genotype alteration
What is the antibiotic target for bacteria?
cell membrane
What is the antibiotic target for fungi?
cell membrane
What is the antibiotic target for viruses?
cell membrane
What are antibiotics for endospores?
there are none
they can be treated with an autoclave
not metabolically active, constantly in lag phase
What are B lactam antibiotics?
all penicillin’s, all semi-synthetic penicillins, cephalosporins
What are B lactamases? (drug with lactam in it)
type of enzyme that is in some antibiotics
How do B lactams and B lactamases relate to one another?
B-lacatamase is an enzyme that bacteria produces to disable beta-lactam antibiotics
What is a non-B lactam cell wall-targeting antibiotic?
vancomycin (has a resistance to B lactamase) and caspofungal walls
What is the barrier against disinfectants and antibiotics
cell membrane
What is the reason for taking multiple antibiotics/antimicrobial drugs at the same time?
-prediagnostic treatment
-treatment of mixed infections
-synergostic effects
-decrease the occurrence of antibiotic resistance
What is vertical gene transfer? (methods and significance)
Acquiring genes from parent organisms during reproduction
What is horizontal gene transfer? (methods and significance)
any transfer of DNA that results in organisms acquiring new genes that did not come directly from parent organisms
What are the scenarios for drug resistance?
Conjugation (and plasmids), Transformation, Transduction (and Transposition)
What is conjugation?
Direct cell-cell transfer of bacterial DNA mediated by plasmids (most efficient mode of horizontal gene transfer)
What is Transformation?
the transfer of genetic material contained in “naked” DNA fragments from a donor cell to a competent recipient cell
What is Transduction?
the transfer of genetic material from one bacterium to another by means of a bacteriophage vector
What is a transposon?
a DNA segment with an insertion sequence at each end
What is a naked virus and how is it transmitted?
transmitted by fecal-oral, more durable
What is an enveloped virus and how is it transmitted?
transmitted by contact, more fragile- made by phospholipid bilayer, easily broken
What is viral antigenicity?
group antigens vs type specific antigens
What are group antigens?
-capsid distinguishes Groups A,B,C
-Antibody vs capsid does NOT neutralize virus
What are type specific antigens?
-H and N proteins
-Antibody vs H neutralizes virus
What is Antigenic Shift?
-occurs in H and N
-MAJOR changes in antigens
-Associated with Group A
-Flu’s segmented genome can re-assort
-Re-assort new H’s or new combos of H and N
-animal flu viruses provide new segments
What is Antigenic Drift?
-occurs in H and N
-MINOR change in antigens
-Associated with Group B
-mutations
What causes antigenic shift and what is the significance of it?
-occurs if a flu virus from an animal population gains the ability to infect humans
-can result in a new Flu A subtype infecting people for the first time
What causes antigenic drift and what is the significance of it?
-caused by point mutations
Influenza A virus drift variants result from the positive selection of spontaneously arising mutants by neutralizing antibodies
-antigenic properties are different enough that the body’s immune system will have a harder time recognizing and fighting against the virus
What is the danger if antigenic shift occurs?
A pandemic may occur if…
-efficient & sustained human-human transmission
-widespread mobility & mortality worldwide
-high proportion of deaths among young adults
What is the difference in structure between a prokaryote and a eukaryote?
Eukaryotes are membrane-bound organelles w/ a complex structure, while Prokaryotes are not membrane bound organelles and have a simple structure
What are the specializations of structure in a prokaryote cell?
-lacking a nuclear membrane
-single circular chromosome for DNA
-lacking histones
-70s ribosomes
- peptidoglycan cell wall
-binary fission
-asexual reproduction
What are the specializations of structure in a eukaryote cell?
- have a nuclear membrane
-paired linear chromosomes for DNA
-histones are present
-80s ribosomes
-cellulose/chitin/ none cell wall
-mitosis/meiosis
-sexual and/or asexual reproduction
What is dangerous to the normal flora?
opportunistic/ nosocomial infections
What does the normal flora do?
-helps prevent growth of other microbes
-produces growth factors for the host
-The “Human Microbiome”
What is sterilization?
removal of ALL microbial life forms
What is disinfection?
removal of PATHOGENS (from inanimate objects)
What is sanitization?
Reducing the microbial counts to meet health codes
What is ELISA?
-serological test: using antibodies to identify an unknown critter
-Direct vs Indirect
-Direct looking for antigen
-Indirect looking for antibodies vs antigen
What are some targets of protozoan infections?
-intestinal tract
-urogenital tract
-blood
-other tissues
True or False:
A protozoa is vegetative when in its feeding form
True
True or False:
A protozoa is a cyst when resting
True
What is tRNA
Transfer RNA
-connects amino acids with another type of RNA during translation
What is transcription?
mRNA synthesis; the process where a strand of RNA is produced against a DNA template
How can mutations be induced?
Induced during replication by….
-chemicals
-radiation (ionizing/non-ionizing)
-some viruses
What do cytokines regulate?
-immune cell differentiation
-proliferation
-effector functions
What do alpha and beta interferons do?
promotes antiviral proteins in non-infected cells
What does Gamma Interferon do?
(by Th1) activates macrophages
What does IL-1 do?
(secreted by macrophages)
-activates T helper cells
-promotes fever and inflammation
-APC cytokine
*If excessively secreted, can lead to shock
What does IL-2 do?
(secreted by Th1)
-promotes Th and Tc growth
-stimulates T cells
What does IL-4 and IL-5 do?
-promote B cell differentiation and proliferation
-promotes antibody (Ig) class switching
-IL-4 stimulates B cells for humoral immunity
What does IL-6 do?
-promotes fever
-stimulates B and T cells
What does IL-10 do?
(secreted by Th2)
-limits gamma interferon, thus Th1 cells
-suppresses macrophage MHC and functions
-anti-inflammatory
What does IL-12 do?
(secreted by macrophages)
-promotes production of Th1 cells
-APC cytokine
