IMED1004 Exam actual questions and
CORRECT answers
William Farr's Law - CORRECT ANSWER William Farr demonstrated that epidemics
decline at a mathematically predictable rate, using empirical observations of a smallpox
epidemic to confirm this
bacterial cell structures - CORRECT ANSWER • Glycocalyx = gel like layer of
polysaccharides surrounding cell
• Capsule = thick, regular shell-like structure made from glycocalyx
• Slime layer = irregular, diffuse glycocalyx
• Helps with bacterial adherence
• Provides protection from immune response
• Pili - or fimbrae - short protein fibres that protrude from cell wall
• Virulence factor with role in adhesion
• Sex pili support the exchange of genetic material between organisms
• Flagella - thin protein tubes that are much longer than pili
• Spin like a boat propeller
• Used for locomotion
= virulence factor - increases disease causing capacity
Gram Positive - CORRECT ANSWER • Purple when exposed to Gram Strain
• Gram-positive bacteria with thicker layers of peptidoglycan can survive in harsher
environments
• Peptidoglycan provides protection to the plasma membrane
,Gram Negative - CORRECT ANSWER • The outer membrane contains
lipopolysaccharides (LPS) = endotoxin
• When Gram negative bacteria die, they liberate LPS which triggers an immune reaction
• Thin peptidoglycan layer
Endospores - CORRECT ANSWER • Form in response to nutritional deprivation or
other unfavourable environmental condition
• Can persist dormant in harsh environments and resume growth should conditions improve
into the future
• The DNA is replicated has cell membrane and protein coat put around it
Fungi - CORRECT ANSWER - Single celled fungi
- Filamentous fungi with branching networks of hyphae
Protozoa - CORRECT ANSWER Many protozoa are free living, others are parasites
4 types
• Flagellates have one or more flagella for locomotion.
• Amoebae move by extending portions of their cytoplasm.
• Ciliates have cilia, like little hairs, that beat for motion. Most are free-living.
• Apicomplexa are generally not motile, most are intracellular parasites.
Viruses - CORRECT ANSWER • Virion = an individual complete viral particle
• Most viruses have one of a few basic structures
• Genetic material surrounded by protein coat = capsid
• Many viruses are also surrounded by an envelope
Opportunistic infection - CORRECT ANSWER when microorganisms of normal
microbiota cause disease
• Sudden access to unaccustomed site
, • Often associated with immunocompromised host with impaired immune defences
Requirements for infectious disease - CORRECT ANSWER 1. Reservoirs provide a
place for pathogens to persist before and after an infection
Zoonosis = human disease for which an animal is a reservoir
2. Transmission to host- Contact transmission(direct/indirect), food- or water-borne
transmission, faecal-oral contamination, Vector transmission(biological, mechanical, vertical)
3.Invasion through a portal of entry.
4. Adherence to host tissue- Glycocalyx, Fimbrae, Viral pathogens often use envelope
glycoproteins, Protozoan parasite uses ventral adhesive disc
5. Infection
6. Evasion of host defence
7. Disease - release exotoxins, produce pathogenic enzymes, Viruses cause disease by killing
or interfering with the normal activities of cells they infect
8. exit via portal of exit and transmission
Antigen-presenting cells (APCs) - CORRECT ANSWER • Macrophages and dendritic
cells
• APCs use TLRs to recognise pathogen sending signals for activation
• They ingest and digest pathogens - Following digestion, small protein fragments of
pathogen are bound on major histocompatibility (MHC)
• APCs migrate to nearby (local, draining) lymph nodes to activate adaptive immune cells
responsible for microbial clearance - T and B cells
T-cells - CORRECT ANSWER • T cells migrate from bone marrow to the thymus
- Helper CD4+ T cells (Th) coordinate entire adaptive response - activate CTLs and B cells
CORRECT answers
William Farr's Law - CORRECT ANSWER William Farr demonstrated that epidemics
decline at a mathematically predictable rate, using empirical observations of a smallpox
epidemic to confirm this
bacterial cell structures - CORRECT ANSWER • Glycocalyx = gel like layer of
polysaccharides surrounding cell
• Capsule = thick, regular shell-like structure made from glycocalyx
• Slime layer = irregular, diffuse glycocalyx
• Helps with bacterial adherence
• Provides protection from immune response
• Pili - or fimbrae - short protein fibres that protrude from cell wall
• Virulence factor with role in adhesion
• Sex pili support the exchange of genetic material between organisms
• Flagella - thin protein tubes that are much longer than pili
• Spin like a boat propeller
• Used for locomotion
= virulence factor - increases disease causing capacity
Gram Positive - CORRECT ANSWER • Purple when exposed to Gram Strain
• Gram-positive bacteria with thicker layers of peptidoglycan can survive in harsher
environments
• Peptidoglycan provides protection to the plasma membrane
,Gram Negative - CORRECT ANSWER • The outer membrane contains
lipopolysaccharides (LPS) = endotoxin
• When Gram negative bacteria die, they liberate LPS which triggers an immune reaction
• Thin peptidoglycan layer
Endospores - CORRECT ANSWER • Form in response to nutritional deprivation or
other unfavourable environmental condition
• Can persist dormant in harsh environments and resume growth should conditions improve
into the future
• The DNA is replicated has cell membrane and protein coat put around it
Fungi - CORRECT ANSWER - Single celled fungi
- Filamentous fungi with branching networks of hyphae
Protozoa - CORRECT ANSWER Many protozoa are free living, others are parasites
4 types
• Flagellates have one or more flagella for locomotion.
• Amoebae move by extending portions of their cytoplasm.
• Ciliates have cilia, like little hairs, that beat for motion. Most are free-living.
• Apicomplexa are generally not motile, most are intracellular parasites.
Viruses - CORRECT ANSWER • Virion = an individual complete viral particle
• Most viruses have one of a few basic structures
• Genetic material surrounded by protein coat = capsid
• Many viruses are also surrounded by an envelope
Opportunistic infection - CORRECT ANSWER when microorganisms of normal
microbiota cause disease
• Sudden access to unaccustomed site
, • Often associated with immunocompromised host with impaired immune defences
Requirements for infectious disease - CORRECT ANSWER 1. Reservoirs provide a
place for pathogens to persist before and after an infection
Zoonosis = human disease for which an animal is a reservoir
2. Transmission to host- Contact transmission(direct/indirect), food- or water-borne
transmission, faecal-oral contamination, Vector transmission(biological, mechanical, vertical)
3.Invasion through a portal of entry.
4. Adherence to host tissue- Glycocalyx, Fimbrae, Viral pathogens often use envelope
glycoproteins, Protozoan parasite uses ventral adhesive disc
5. Infection
6. Evasion of host defence
7. Disease - release exotoxins, produce pathogenic enzymes, Viruses cause disease by killing
or interfering with the normal activities of cells they infect
8. exit via portal of exit and transmission
Antigen-presenting cells (APCs) - CORRECT ANSWER • Macrophages and dendritic
cells
• APCs use TLRs to recognise pathogen sending signals for activation
• They ingest and digest pathogens - Following digestion, small protein fragments of
pathogen are bound on major histocompatibility (MHC)
• APCs migrate to nearby (local, draining) lymph nodes to activate adaptive immune cells
responsible for microbial clearance - T and B cells
T-cells - CORRECT ANSWER • T cells migrate from bone marrow to the thymus
- Helper CD4+ T cells (Th) coordinate entire adaptive response - activate CTLs and B cells
