HSS 1100 EXAM QUESTIONS AND
ANSWERS ALL CORRECT
What is the current vaccine for whooping cough based on? - Answer-A heat-killed
organism including pertussis toxin, filamentous hemagglutinin, and adenylate cyclase.
What is the biochemical classification of Gram-negative bacteria based on? - Answer-
Ability to ferment lactose to gas and acid, and other biochemical properties.
What does a positive tuberculin test indicate? - Answer-That the individual has been
infected with Mycobacterium tuberculosis at some time.
What is the causative agent of tuberculosis? - Answer-Mycobacterium tuberculosis.
What is the primary mode of transmission for leprosy? - Answer-Primarily human to
human through respiratory droplets.
What is the role of antibiotics in treating H. pylori infections? - Answer-A combination of
antibiotics and proton pump inhibitors is most successful.
What are the symptoms of diarrhea caused by enterotoxins? - Answer-Watery diarrhea
without systemic symptoms, such as fever.
What is the significance of the term 'opportunistic pathogen'? - Answer-An organism
that causes disease primarily in individuals with compromised immune systems.
What are the three major surface antigens of enteric bacteria? - Answer-O antigen, K
antigen, and H antigen.
What is the primary complex in tuberculosis? - Answer-The local lesion in the lung,
draining lymphatics, and reacting lymph nodes formed after infection.
What are the basic structural components of viruses? - Answer-Viruses consist of
nucleic acids and, in some cases, a protein shell known as a capsid.
How do viruses replicate within host cells? - Answer-Viruses enter cells and divert the
synthetic processes of those cells towards their own replication.
,What distinguishes prokaryotes from eukaryotes? - Answer-Prokaryotes, like bacteria,
have a rigid cell wall and circular chromosomes, while eukaryotes have organized
genetic material in a nucleus.
What are mycoplasmas? - Answer-Mycoplasmas are similar to bacteria but lack a rigid
cell wall, making them more delicate.
What is the role of normal bacterial flora in human health? - Answer-Normal flora
protects against infection, participates in metabolism, and can confuse laboratory
results.
What are the two types of bacterial populations in the human body? - Answer-Resident
flora, which are permanent, and transient flora, which are temporary and can displace
resident flora.
How does antibiotic therapy affect normal flora? - Answer-Antibiotic therapy can disturb
the ecology of normal flora, potentially leading to conditions like antibiotic-induced
diarrhea.
What is the significance of mechanical barriers in host defense? - Answer-The skin acts
as a barrier to prevent bacterial invasion into deeper tissues.
What is the first requirement for bacterial invasion? - Answer-Bacteria must adhere to
the host, which involves specific ligands binding to receptors on mammalian cells.
What cells are primarily responsible for phagocytosis? - Answer-Macrophages and
blood neutrophils (polymorphonuclear cells) are the main cells that ingest and kill
bacteria.
What protective mechanism do some bacteria use against phagocytosis? - Answer-
Some bacteria, like Streptococcus pneumoniae, surround themselves with a
polysaccharide capsule to prevent engulfment by phagocytic cells.
What is the outcome of a bacterial infection determined by? - Answer-The outcome is
determined by bacterial pathogenicity factors and the host's response to those factors.
What are the clinical implications of normal flora? - Answer-Normal flora can protect
against infections, aid in metabolism, and complicate laboratory interpretations.
What can happen when a single bacterial species predominates in a normally diverse
ecosystem? - Answer-Infection can occur if a single species becomes predominant or
invades a normally sterile site.
What role does adherence play in bacterial infections? - Answer-Adherence is crucial
for bacterial invasion, as bacteria must attach to host tissues to initiate infection.
, What is the effect of host defenses on normal flora? - Answer-Deficiencies in host
defenses may lead to infections by organisms that are normally non-pathogenic.
What is the importance of the skin in the immune system? - Answer-The skin is a critical
mechanical barrier and is extensively colonized by organisms that can initiate infections
if the barrier is breached.
How can disturbances in normal flora lead to nutritional deficiencies? - Answer-Certain
microorganisms in the gut synthesize vitamin K; disturbances can result in secondary
nutritional deficiencies.
What is the relationship between normal flora and antibiotic therapy? - Answer-Antibiotic
therapy can disrupt normal flora, leading to potential infections or complications.
What is the role of antibodies in response to bacterial capsules? - Answer-The host may
produce antibodies to bacterial capsules to counteract their protective effects against
phagocytosis.
What is the significance of the balance in normal flora? - Answer-A balanced ecosystem
of normal flora prevents the dominance of pathogenic organisms.
What factors influence the outcome of bacterial infections? - Answer-Factors include
bacterial pathogenicity and the host's immune response mechanisms.
What is opsonization? - Answer-The process where antibodies bind to the capsule of
bacteria, altering its surface to facilitate phagocyte uptake.
How do antibodies function against bacteria? - Answer-They may act as opsonins or
directly kill the organisms.
What is the role of complement in the immune response? - Answer-Complement is a
system of plasma proteins that helps resist bacterial infection and enhances the
immune response.
Which types of bacteria are killed by activated macrophages? - Answer-Bacteria such
as Mycobacterium tuberculosis and Legionella species.
What are exotoxins? - Answer-Proteins produced by bacteria that can damage host
tissues and exert effects at locations distant from their site of synthesis.
How does the host defend against exotoxins? - Answer-The host defense against
exotoxins is primarily through antibodies.
What determines the outcome of an invasive infection? - Answer-The interaction
between host defenses and the pathogenicity mechanisms of the bacteria.
ANSWERS ALL CORRECT
What is the current vaccine for whooping cough based on? - Answer-A heat-killed
organism including pertussis toxin, filamentous hemagglutinin, and adenylate cyclase.
What is the biochemical classification of Gram-negative bacteria based on? - Answer-
Ability to ferment lactose to gas and acid, and other biochemical properties.
What does a positive tuberculin test indicate? - Answer-That the individual has been
infected with Mycobacterium tuberculosis at some time.
What is the causative agent of tuberculosis? - Answer-Mycobacterium tuberculosis.
What is the primary mode of transmission for leprosy? - Answer-Primarily human to
human through respiratory droplets.
What is the role of antibiotics in treating H. pylori infections? - Answer-A combination of
antibiotics and proton pump inhibitors is most successful.
What are the symptoms of diarrhea caused by enterotoxins? - Answer-Watery diarrhea
without systemic symptoms, such as fever.
What is the significance of the term 'opportunistic pathogen'? - Answer-An organism
that causes disease primarily in individuals with compromised immune systems.
What are the three major surface antigens of enteric bacteria? - Answer-O antigen, K
antigen, and H antigen.
What is the primary complex in tuberculosis? - Answer-The local lesion in the lung,
draining lymphatics, and reacting lymph nodes formed after infection.
What are the basic structural components of viruses? - Answer-Viruses consist of
nucleic acids and, in some cases, a protein shell known as a capsid.
How do viruses replicate within host cells? - Answer-Viruses enter cells and divert the
synthetic processes of those cells towards their own replication.
,What distinguishes prokaryotes from eukaryotes? - Answer-Prokaryotes, like bacteria,
have a rigid cell wall and circular chromosomes, while eukaryotes have organized
genetic material in a nucleus.
What are mycoplasmas? - Answer-Mycoplasmas are similar to bacteria but lack a rigid
cell wall, making them more delicate.
What is the role of normal bacterial flora in human health? - Answer-Normal flora
protects against infection, participates in metabolism, and can confuse laboratory
results.
What are the two types of bacterial populations in the human body? - Answer-Resident
flora, which are permanent, and transient flora, which are temporary and can displace
resident flora.
How does antibiotic therapy affect normal flora? - Answer-Antibiotic therapy can disturb
the ecology of normal flora, potentially leading to conditions like antibiotic-induced
diarrhea.
What is the significance of mechanical barriers in host defense? - Answer-The skin acts
as a barrier to prevent bacterial invasion into deeper tissues.
What is the first requirement for bacterial invasion? - Answer-Bacteria must adhere to
the host, which involves specific ligands binding to receptors on mammalian cells.
What cells are primarily responsible for phagocytosis? - Answer-Macrophages and
blood neutrophils (polymorphonuclear cells) are the main cells that ingest and kill
bacteria.
What protective mechanism do some bacteria use against phagocytosis? - Answer-
Some bacteria, like Streptococcus pneumoniae, surround themselves with a
polysaccharide capsule to prevent engulfment by phagocytic cells.
What is the outcome of a bacterial infection determined by? - Answer-The outcome is
determined by bacterial pathogenicity factors and the host's response to those factors.
What are the clinical implications of normal flora? - Answer-Normal flora can protect
against infections, aid in metabolism, and complicate laboratory interpretations.
What can happen when a single bacterial species predominates in a normally diverse
ecosystem? - Answer-Infection can occur if a single species becomes predominant or
invades a normally sterile site.
What role does adherence play in bacterial infections? - Answer-Adherence is crucial
for bacterial invasion, as bacteria must attach to host tissues to initiate infection.
, What is the effect of host defenses on normal flora? - Answer-Deficiencies in host
defenses may lead to infections by organisms that are normally non-pathogenic.
What is the importance of the skin in the immune system? - Answer-The skin is a critical
mechanical barrier and is extensively colonized by organisms that can initiate infections
if the barrier is breached.
How can disturbances in normal flora lead to nutritional deficiencies? - Answer-Certain
microorganisms in the gut synthesize vitamin K; disturbances can result in secondary
nutritional deficiencies.
What is the relationship between normal flora and antibiotic therapy? - Answer-Antibiotic
therapy can disrupt normal flora, leading to potential infections or complications.
What is the role of antibodies in response to bacterial capsules? - Answer-The host may
produce antibodies to bacterial capsules to counteract their protective effects against
phagocytosis.
What is the significance of the balance in normal flora? - Answer-A balanced ecosystem
of normal flora prevents the dominance of pathogenic organisms.
What factors influence the outcome of bacterial infections? - Answer-Factors include
bacterial pathogenicity and the host's immune response mechanisms.
What is opsonization? - Answer-The process where antibodies bind to the capsule of
bacteria, altering its surface to facilitate phagocyte uptake.
How do antibodies function against bacteria? - Answer-They may act as opsonins or
directly kill the organisms.
What is the role of complement in the immune response? - Answer-Complement is a
system of plasma proteins that helps resist bacterial infection and enhances the
immune response.
Which types of bacteria are killed by activated macrophages? - Answer-Bacteria such
as Mycobacterium tuberculosis and Legionella species.
What are exotoxins? - Answer-Proteins produced by bacteria that can damage host
tissues and exert effects at locations distant from their site of synthesis.
How does the host defend against exotoxins? - Answer-The host defense against
exotoxins is primarily through antibodies.
What determines the outcome of an invasive infection? - Answer-The interaction
between host defenses and the pathogenicity mechanisms of the bacteria.
