IMB 401 EXAM #3 QUESTIONS AND ANSWERS
Bacteria - correct answer -The smallest known independently living cells.
-1 mm width
-smallest overlap poxviruses
Prokaryotic Cell Plan - correct answer NO nucleus, mitochondria, ER, Golgi. Interior:
cytosol, ribosomes, nucleoid. Exterior: capsule, appendages. Chemical elements:
proteins, DNA, RNA. Unique ones: peptidoglycan and LPS.
Prokaryotic Cell Core - correct answer Cytoplasm: granular (EM) and ribosome factory
Nucleoid: fibrous (EM) and single chromosome
5 Basic Steps of Infection - correct answer 1.) Adherence to host cells for colonization
2.) Local proliferation & evasion of host defense systems
3.) Tissue damage
4.) Invasion
5.) Dissemination within host & spread to others
Microbial pathogenicity - correct answer ability of microbes to cause disease
Koch's Postulates - correct answer 1.) Microbe associated with lesions and symptoms
of the disease.
2.) Microbe must be isolated from lesion of disease and grown as pure culture.
3.) Pure culture of microbe, when inoculated into a susceptible host must reproduce the
disease in the experimental host.
4.) Microbe must be re-isolated in pure culture from the experimentally infected host.
Stanley Falkow - correct answer Father of Molecular Microbial Pathogenesis. Proposed
molecular Koch's Postulates in 1988
Symbionts - correct answer All host-associated microbes are symbionts with variation
(i.e. Commensals, mutualists, pathobionts, pathogens).
Commensals - correct answer Colonize host and receive benefits from host
Mutualist - correct answer symbiosis that is beneficial to both organisms involved
(microbe & host)
Pathobionts - correct answer Can colonize as a commensal to mutualist, but
environment can drive towards pathogenic. (i.e. Inhibit bodily processes, cause
inflammation or infectious disease).
Pathogens - correct answer interaction with host is pathogenic; disease causing agents
, Virulence - correct answer ACTUAL harm that is caused by the bacteria (i.e. The
outcome)
Pathogenicity - correct answer POTENTIAL to cause disease. Boundaries between
commensal, parasite, and mutualism is fluid, and should be regarded as a continuum
rather than as fixed categories in nature.
Experimentally, how could you determine virulence? - correct answer
What usually determines whether a microbe is pathogenic? - correct answer The host
and ecological context. (i.e. Emerging Infectious Diseases such has HIV and Ebola, or
Reemerging Infectious Diseases such has Influenza A, Measles).
Why do bacterial pathogens keep emerging? - correct answer Antigenic Drift/NO
Appears most EID's are microbes long present in the environment but people have only
been recently exposed or were unable to detect so far in the clinical microbiology lab!
Other factors: Vaccination compliance, occupational exposures
Detection of EID's and Re-EID's - correct answer Molecular technics (PCR, 16s rrna),
mass spectrometry (MALDI-TOF)
Cocci - correct answer Spherical bacteria, pairs, chains, clusters
Bacilli - correct answer Rod shaped bacteria, large, small, straight, curved, Coccobacilli
Gram-positive cell wall - correct answer thick peptidoglycan layer, surface proteins,
teichoic acid, lipoteichoic acid. Porous cell wall allows for water, oxygen, and other
things to get in.
Gram-negative cell wall - correct answer Thin peptidoglycan layer, outer membrane,
Periplasmic space
What is peptidoglycan? - correct answer Sugar molecule backbone, amino acid side
chains, enzymatic cross-linking of peptide chains, 3-D matrix, changes with the
environment (not static)
Gram-negative outer membrane - correct answer Permeability barrier, LPS endotoxin,
outer membrane proteins (omps)
(i.e. Porins, matrix proteins, adherence, transport (nutrients and antibiotics)).
Lipopolysaccharide (LPS) - correct answer O side chain, core polysaccharide, Lipid A-
toxic, THE endotoxin. Can send you into toxic shock syndrome
Acid-fast stain - correct answer Cell wall difficult to stain, time/heat/penetrating agents,
once stained resist decolorization, Myobacterium tuberculosis
Bacteria - correct answer -The smallest known independently living cells.
-1 mm width
-smallest overlap poxviruses
Prokaryotic Cell Plan - correct answer NO nucleus, mitochondria, ER, Golgi. Interior:
cytosol, ribosomes, nucleoid. Exterior: capsule, appendages. Chemical elements:
proteins, DNA, RNA. Unique ones: peptidoglycan and LPS.
Prokaryotic Cell Core - correct answer Cytoplasm: granular (EM) and ribosome factory
Nucleoid: fibrous (EM) and single chromosome
5 Basic Steps of Infection - correct answer 1.) Adherence to host cells for colonization
2.) Local proliferation & evasion of host defense systems
3.) Tissue damage
4.) Invasion
5.) Dissemination within host & spread to others
Microbial pathogenicity - correct answer ability of microbes to cause disease
Koch's Postulates - correct answer 1.) Microbe associated with lesions and symptoms
of the disease.
2.) Microbe must be isolated from lesion of disease and grown as pure culture.
3.) Pure culture of microbe, when inoculated into a susceptible host must reproduce the
disease in the experimental host.
4.) Microbe must be re-isolated in pure culture from the experimentally infected host.
Stanley Falkow - correct answer Father of Molecular Microbial Pathogenesis. Proposed
molecular Koch's Postulates in 1988
Symbionts - correct answer All host-associated microbes are symbionts with variation
(i.e. Commensals, mutualists, pathobionts, pathogens).
Commensals - correct answer Colonize host and receive benefits from host
Mutualist - correct answer symbiosis that is beneficial to both organisms involved
(microbe & host)
Pathobionts - correct answer Can colonize as a commensal to mutualist, but
environment can drive towards pathogenic. (i.e. Inhibit bodily processes, cause
inflammation or infectious disease).
Pathogens - correct answer interaction with host is pathogenic; disease causing agents
, Virulence - correct answer ACTUAL harm that is caused by the bacteria (i.e. The
outcome)
Pathogenicity - correct answer POTENTIAL to cause disease. Boundaries between
commensal, parasite, and mutualism is fluid, and should be regarded as a continuum
rather than as fixed categories in nature.
Experimentally, how could you determine virulence? - correct answer
What usually determines whether a microbe is pathogenic? - correct answer The host
and ecological context. (i.e. Emerging Infectious Diseases such has HIV and Ebola, or
Reemerging Infectious Diseases such has Influenza A, Measles).
Why do bacterial pathogens keep emerging? - correct answer Antigenic Drift/NO
Appears most EID's are microbes long present in the environment but people have only
been recently exposed or were unable to detect so far in the clinical microbiology lab!
Other factors: Vaccination compliance, occupational exposures
Detection of EID's and Re-EID's - correct answer Molecular technics (PCR, 16s rrna),
mass spectrometry (MALDI-TOF)
Cocci - correct answer Spherical bacteria, pairs, chains, clusters
Bacilli - correct answer Rod shaped bacteria, large, small, straight, curved, Coccobacilli
Gram-positive cell wall - correct answer thick peptidoglycan layer, surface proteins,
teichoic acid, lipoteichoic acid. Porous cell wall allows for water, oxygen, and other
things to get in.
Gram-negative cell wall - correct answer Thin peptidoglycan layer, outer membrane,
Periplasmic space
What is peptidoglycan? - correct answer Sugar molecule backbone, amino acid side
chains, enzymatic cross-linking of peptide chains, 3-D matrix, changes with the
environment (not static)
Gram-negative outer membrane - correct answer Permeability barrier, LPS endotoxin,
outer membrane proteins (omps)
(i.e. Porins, matrix proteins, adherence, transport (nutrients and antibiotics)).
Lipopolysaccharide (LPS) - correct answer O side chain, core polysaccharide, Lipid A-
toxic, THE endotoxin. Can send you into toxic shock syndrome
Acid-fast stain - correct answer Cell wall difficult to stain, time/heat/penetrating agents,
once stained resist decolorization, Myobacterium tuberculosis
