Microbial Diversity and Pathogenesis Flashcards
How do microbes avoid soluble immunity factors?
- Avoid complement fixation
- Destroy Ab
- Avoid eliciting/detection by Ab
How is Toxoplasmosis diagnosed?
- Serology (ELISA for anti-toxiplasma serum antibodies) - blood test
- PCR
- Histology (detection of tissue cysts) or gross pathology (retina)
Define
Merozoites
a small amoeboid sporozoan trophozoite (as of a malaria parasite) produced by schizogony that is capable of initiating a new sexual or asexual cycle of development
True or False:
Normal flora can become pathogenic
True
These are termed opportunistic pathogens
Definition
lacking a cell nucleus
Anucleate cells
True or False:
Toxoplasma infect phagocytes by being phagocytosed
False
The invade the phagocytes
Definition
an infection caused by pathogens (bacteria, viruses, fungi, or protozoa) that take advantage of an opportunity not normally available, such as a host with a weakened immune system, an altered microbiota (such as a disrupted gut microbiota), or breached integumentary barriers
Opportunistic pathogens
Define
Phage therapy
the therapeutic use of bacteriophages to treat pathogenic bacterial infections
Definition
symbiosis which is beneficial to both organisms involved
Mutualism
What are human mycoses caused by?
True fungal pathogens and opportunistic pathogens
What are the differences between prokaryotes and eukaryotes?
What causes Giardiasis?
- G. intestinalis*
- G. lamblia*
Definition
the cells and tissues of a host that support growth of a particular virus or bacterium
Tissue tropism
Define
E. coli
a bacterium commonly found in the intestines of humans and other animals, some strains of which can cause severe food poisoning
Definition
DNA sequences that can move around the genome, changing their number of copies or simply changing their location, often affecting the activity of nearby genes
Mobile genetic element
Define
Anucleate cells
lacking a cell nucleus
Define
16S rRNA
the component of the 30S small subunit of a prokaryotic ribosome that binds to the Shine-Dalgarno sequence
What is the normal flora of the lower respiratory tract?
It does not usually have microbiota
Definition
molecules shared by groups of related microbes that are essential for the survival of those organisms and are not found associated with mammalian cells
PAMPs
What is the bulk of the cell wall comprised of in Acid-fast bacteria?
Unique types of lipids such as mycolic acid
Definition
starting from the beginning
De novo
The relationship between the normal flora and the host is:
Select one:
a. mutualistic and parasitic
b. symbiotic
c. paratism and commensalism
d. commensalism and mutalism
The relationship between the normal flora and the host is:
Select one:
a. mutualistic and parasitic
b. symbiotic
c. paratism and commensalism
d. commensalism and mutalism
What does viral protain VP16 do in class 1 viruses?
Stimulates cellular reverse transcriptase to transcribe IE genes
How do viruses lyse cells?
Viroporins - hydrophobic proteins, interact with and disrupt membranes
Picornaviruses - VP2
Which section of the IgA molecule does IgA protease cleave?
The hinge region
Definition
recovering from an illness or medical treatment
Convalescent
Define
Resident flora
The microorganisms that usually occupy a particular body site
Definition
a compound present in the walls of Gram-positive bacteria. It is a polymer of ribitol or glycerol phosphate
Teichoic acid
Define
Adhesins –
cell-surface components or appendages of bacteria that facilitate adhesion or adherence to other cells or to surfaces, usually the host they are infecting or living in
What is unique to Mycoplamataceae bacteria?
They completely lack a cell wall
Definition
any of a group of spore-producing organisms feeding on organic matter, including moulds, yeast, mushrooms, and toadstools
Fungi
Definition
a common bacterium that lives on the skin or in the nose and in most situations it is harmless. However, if it enters the body through a cut in the skin, it can cause a range of mild to severe infections, which may cause death in some cases. Also known as S. aureus
Golden staph
Define
Invasins
Any of a class of proteins associated with the penetration of bacteria into mammalian cells
Definition
a carbohydrate-enriched coating that covers the outside of many eukaryotic cells and prokaryotic cells, particularly bacteria
Glycocalyx
Describe spherical viruses
Icosahedral ordered symmetry
Formed by repeating units of protein
A regular polyhedron with 20 triangular faces
Define
Operon
a unit made up of linked genes which is thought to regulate other genes responsible for protein synthesis
Definition
an organism consisting of a cell or cells in which the genetic material is DNA in the form of chromosomes contained within a distinct nucleus. They include all living organisms other than the eubacteria and archaea
Eukaryotes
Definition
a supergroup of protists that are defined by an asymmetrical appearance with a feeding groove that is “excavated” from one side; it includes various types of organisms which are parasitic, photosynthetic and heterotrophic predators
Excavata
Define
A-B toxins –
two-component protein complexes secreted by a number of pathogenic bacteria. They can be classified as Type III toxins because they interfere with internal cell function
What stimulates transcription of early genes in class 1 viruses?
IE gene proteins
What makes up most of the cell wall of a Gram-positive bacteria?
Peptidoglycan
Definition
a major constituent of the cell wall of gram-positive bacteria
Lipoteichoic acid
What is the step-wise gene expression of viruses?
Immediate early
Early
Late (Assembly and egress)
Definition
the capsid of a virus with the enclosed nucleic acid
Nucleocapsid
What is the ideal media to grow bacteria from the respiratory tract?
Horse blood agar
Definition
a microscopic parasite that causes the diarrheal illness known as giardiasis
Giardia
True or False:
Candida albicans can form biofilms
True
How is Toxoplasmosis transmitted?
Ingestion of raw/undercooked cyst-infected meat
Contaminated drinking water
Ingestion of raw/undercooked vegetables
Ingestion of cat feces
Describe the pathogenesis of Giardiasis
- Cysts undergo developmental change in duodenum and form trophozoites
- Trophozoites attach to duodenal epithelial cells via a sucking disk
- Feed on mucosal secretions and grow and multiply, interfering with intestinal absorption
Define
Transcytosis
a type of transcellular transport in which various macromolecules are transported across the interior of a cell
Definition
a blood protein produced in response to and counteracting a specific antigen. They combine chemically with substances which the body recognizes as alien, such as bacteria, viruses, and foreign substances in the blood
Antibodies (Ab) –
Bacterial siderophores:
Select one:
a. Act as receptors for nitrogen-binding host proteins
b. Are high molecular weight membrane proteins
c. Allow the normal flora to out-compete pathogens
d. Are used to chelate iron in the environment
Bacterial siderophores:
Select one:
a. Act as receptors for nitrogen-binding host proteins
b. Are high molecular weight membrane proteins
c. Allow the normal flora to out-compete pathogens
d. Are used to chelate iron in the environment
Eukaryotes
Select one:
a. Carry out all it’s functions through the cytoplasmic membrane
b. Have a membrane delimited nucleus
c. are only bacteria
d. mycolic acid on the cell wall
Eukaryotes
Select one:
a. Carry out all it’s functions through the cytoplasmic membrane
b. Have a membrane delimited nucleus
c. are only bacteria
d. mycolic acid on the cell wall
Definition
a protein released by animal cells, usually in response to the entry of a virus, which has the property of inhibiting virus replication.
Interferon
True or False:
The vast majority of DNA sequences in human blood are viral
True
Definition
a type of transmission that occurs when bacteria or viruses travel on dust particles or on small respiratory droplets that may become aerosolized when people sneeze, cough, laugh, or exhale
Airborne transmission
Definition
a differential stain used to identify acid-fast organisms such as members of the genus Mycobacterium
Acid-fast stain
Definition
infection with candida, especially as causing oral or vaginal thrush
Candidiasis
Adhesion is mediated by which structures?
- Pili/fibriae
- Afibrial adhesins
- Bacterial capsules
Definition
the most common bacterial cytotoxic proteins and are required for virulence in a large number of important pathogens that generally disrupt host cell membranes, but they can have additional effects independent of pore formation
Pore-forming toxins
How can Toxoplasmosis be prevented?
- Wear gloves when gardening, carefull cleaning of cat litter trays especially if you are pregnant (or thinking about it)
- Wash hads properly
- Cook all meat thoroughly
- Wash (and peel) your veggies (selected countries)
- Clean surfaces and kitchen utensils to prevent cross-contamination
Define
Transient flora
Microbes inhabiting a body surface or cavity for a brief period of time, usually as a result of their promotion and selection by antibiotic therapy, chemotherapy, hospitalization, illness, or surgery
Definition
a thin but robust layer of mucilage adhering to a solid surface and containing a community of bacteria and other microorganisms
Biofilms
Definition
infections that have been caught in a hospital and are potentially caused by organisms that are resistant to antibiotics
Noscomial infections
Define
Asymptomatic carrier
a person or other organism that has become infected with a pathogen, but that displays no signs or symptoms
What are the three main vectors for horizontal gene transfer?
Plasmids
Bacteriophages
Transposons
Definition
a gene that protects a cell from one step on the path to cancer
Tumour-supressor gene
What is the name of a parasitic organism that lives within the host?
Endoparasite
Define
Bacteriocins
a protein produced by bacteria of one strain and active against those of a closely related strain
What happens in cerebral malaria?
The infected RBCs obstruct the blood vessels in the brain
Define
Gram positive
bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their cell wall.
Define
De novo
starting from the beginning
Definition
the transmission of pathogens through vehicles such as water, food, and air
Vehicle transmission
Definition
the type of ribosome found in bacteria and archaea that are comprised of a small 30S subunit and large 50S subunit
70S ribosome
Define
Antibodies (Ab) –
a blood protein produced in response to and counteracting a specific antigen. They combine chemically with substances which the body recognizes as alien, such as bacteria, viruses, and foreign substances in the blood
What are the three protein exotoxins?
Membrane-disrupting toxins
A-B toxins
Superantigens
What is considered the 5th Koch’s postulate?
Effective therapeutic or preventative measure(s) should eliminate disease
How is cryptosporidium prevented?
- Exclude people with Cryptosporidium infection from childcare, preschool, school and work until there has been no diarrhea for 24 hours
- People who have diarrhea should not use swimming pools or spas for 14 days after the symptoms have stopped
- Pasterurisation and boiling as control measures
- Wash hands
Define
Virulence factor
Factor(s) required by the microorganism that enable it to cause disease
How can bacteria inhibit the phagolysosome?
- Block fusion to lysosomes
- Lyse phagosomal membrane
- Block/be resistant to acidification
- Block assemblt of NADPH oxidase
Define
Incubatory
the period between exposure to an infection and the appearance of the first symptoms
True or False:
Fungi can produce spores through both sexual or asexual life cycles
True
Define
Toxoplasmosis
a disease caused by toxoplasmas, transmitted chiefly through undercooked meat, soil, or in cat faeces. Symptoms of infection generally pass unremarked in adults, but can be dangerous to unborn children.
Definition
A chain of easily disrupted fungal cells that is intermediate between a chain of budding cells and a true hypha, marked by constrictions rather than septa at the junctions
Elogate pseudohyphae
What are the two major parts of the LPS later?
Lipid A
O-specific polysaccharide side chain (O antigen)
Cryptosporidium oocysts are resistant to what and susceptible to what?
Resistant to chlorination but are killed by conventional cooking or boiling
Define
Trophozoites
a growing stage in the life cycle of some sporozoan parasites, when they are absorbing nutrients from the host
What are the common nematode parasites that infect humans?
Roundworms
Hookworms
Pin or threadworms
Which areas do bacteria colonise that have poor access for antibodies?
Inside cells
Epidermis
CNS
Gall bladder
Cysts
What do endospores contain?
DNA, ribosomes and large amounts of dipicolinic acid in the core (aids dormancy)
Define
Macrophages
a large phagocytic cell found in stationary form in the tissues or as a mobile white blood cell, especially at sites of infection
Most fungal pathogens of humans are opportunistic, which means that:
Select one:
a. They infect a host at first contact
b. They need to switch morphology
c. They mostly infect immunosuppressed subjects
d. They require a specific infection route
Most fungal pathogens of humans are opportunistic, which means that:
Select one:
a. They infect a host at first contact
b. They need to switch morphology
c. They mostly infect immunosuppressed subjects
d. They require a specific infection route
How is Cryptosporidium transmitted?
From animal reservoirs in contaminated food or water (manu birds and mammal shed oocysts in feces)
Definition
a type of transcellular transport in which various macromolecules are transported across the interior of a cell
Transcytosis
Definition
an organism that makes ATP by aerobic respiration if oxygen is present, but is capable of switching to fermentation or anaerobic respiration if oxygen is absent
Faculative anaerobes
Define
Archaea
microorganisms which are similar to bacteria in size and simplicity of structure but radically different in molecular organization. They are now believed to constitute an ancient group which is intermediate between the bacteria and eukaryotes
Definition
any unicellular fungus that reproduces vegetatively by budding or fission, including forms such as candida that can cause disease
Yeast
The Plaque Assay:
Select one:
a. A) Is based on the fact that infection is latent in the majority of infected cells, leading to the formation of plaques of dead cells only by the non-latent viruses.
b. A) Is based on the fact that each virion initially infects a single cell, and its progeny infects neighbouring cells, leading to the formation of a plaque of dead cells.
c. Provides a measure of the efficiency of viral replication
d. Provides a measure of the size of the viral genome.
The Plaque Assay:
Select one:
a. A) Is based on the fact that infection is latent in the majority of infected cells, leading to the formation of plaques of dead cells only by the non-latent viruses.
b. A) Is based on the fact that each virion initially infects a single cell, and its progeny infects neighbouring cells, leading to the formation of a plaque of dead cells.
c. Provides a measure of the efficiency of viral replication
d. Provides a measure of the size of the viral genome.
Define
S. epidermidis
a gram-positive, coagulase-negative cocci that is a part of our skins normal flora
Where are Toxoplasma cysts activated?
In the gut
How is Malaria transmitted?
Malaria parasites are transmitted from one person to another by the female Anopheles mosquito. The males do not transmit the disease as the feed only on plant juices
What is the eclipse period?
Stage where no new viruses are present in host cells
Define
Pathogenicity
the property of causing disease
How can bacteria avoid being recognised or inhibit internalisation?
- Avoiding opsonisation
- Forming capsules (hides PAMPs)
- Forming biofilms
Definition
an organism that lives in or on an organism of another species (its host) and benefits by deriving nutrients at the other’s expense
Parasites
What cells do Toxoplasma infect?
Invasion of multiple cells types including moncytes, macrophages, dendritic cells
True or False:
Viruses are only able to grow within a cell
False
Viruses do not grow, but they can only assemble within cells
What is the life cycle of a roundworm
Definition
a unit made up of linked genes which is thought to regulate other genes responsible for protein synthesis
Operon
Definition
collection of nucleic acids, both RNA and DNA, that make up the viral community associated with a particular ecosystem or holobiont
Virome
True or False
Disease causing toxins may be found in the cell wall of a bacteria
False
Disease causing toxins may be found in the outer membrane of a bacteria
Definition
the genetic material of a bacteriophage, incorporated into the genome of a bacterium and able to produce phages if specifically activated
Prophage
Define
Bacteriophages
a virus which parasitizes a bacterium by infecting it and reproducing inside it
Definition
distinct class of genomic islands acquired by microorganisms through horizontal gene transfer. They are found in both animal and plant pathogen
Pathogenicity island
Definition
a staining technique for the preliminary identification of bacteria, in which a violet dye is applied, followed by a decolorizing agent and then a red dye. The cell walls of certain bacteria (denoted Gram-positive ) retain the first dye and appear violet, while those that lose it (denoted Gram-negative ) appear red
Gram stain
What are A-B toxins and what do they do?
Binary toxins with a catalytic ‘warhead’ (A) and a targeting component (B). It causes post-translational modifications of polypeptides
E. coli is not present in all humans
Select one:
True
False
E. coli is not present in all humans
Select one:
True
False
Definition
Any of many parasitic protozoans, of the class Sporozoa, that reproduce alternately sexually and asexually via spores; they are responsible for diseases such as malaria
Sporozones
Definition
bacteria that cannot live outside the host cell
Obligate intracellular pathogens
How do bacteria avoid eliciting or detection by antibodies?
- Remain inside host cells
- Host mimicry
- Coat with host proteins
- Colonise sites with poor access for antibodies
- Keep ahead of the immune system
Which enzymes needed by viruses to convert their nucleic acid into mRNA must be encoded by the virus itself?
RNA-dependent RNA polymerase
RNA-dependent reverse transcriptase
How do you treat Candidiasis?
- There is no satisfactory treatment currently
- Antifungals used for cutaneous lesions and systemic candidiasis
Define
Lytic cycle
one of the two cycles of viral reproduction that results in the destruction of the infected cell and its membrane
What makes up the bacterial cytoplasm?
Cytosol
Nucleoid - chromosome
Ribosomes
Inclusion bodies (e.g. endospores)
Cytoskeletal components
Definition
small masses of lymphatic tissue found throughout the ileum region of the small intestine
Peyer’s Patch
Define
Naked virus
A virus lacking the viral envelope
Define
Cytopathic
structural changes in host cells that are caused by viral invasion
What are the symptoms of Cryptosporidiosis?
Diarrhea
Stomach pain
Nausea
Fever
Fatigue
Define
Acid-fast bacteria
bacteria with a cell wall rich in special acids, called mycolic acids
When are virulence genes expressed?
When the bacteria sense a specific niche or in response to population density
How many types of viruses are considered in the Baltimore Classification Scheme?
7
Why do antibiotics that target ribosomes not effect human cells?
The antibiotics act on the 70S ribosomes unit but has no effect on the 80S units found in human cells
How are healthy individuals treated for Toxoplasmosis?
- Usually no treatment necessary, symptoms abate within weeks to months
- But… infection leads to chronic infection (may need later treatment)
- Most cases go undiagnosed and remain clinically unapparent
Definition
the severity or harmfulness of a disease or poison
Virulence
Define
Infection
a proliferation of a harmful strain of bacteria on or inside the body
Define
Plasmid
a genetic structure in a cell that can replicate independently of the chromosomes, typically a small circular DNA strand in the cytoplasm of a bacterium or protozoan
Define
Prophage
the genetic material of a bacteriophage, incorporated into the genome of a bacterium and able to produce phages if specifically activated
True or False:
(-) ssRNA viruses, but not (+) ssRNA viruses must deliver RNA-dependent RNA polymerase protein with genome
True
Define
Excavata
a supergroup of protists that are defined by an asymmetrical appearance with a feeding groove that is “excavated” from one side; it includes various types of organisms which are parasitic, photosynthetic and heterotrophic predators
Koch’s postulates are four criteria that are used to determine whether a disease is caused by a particular microorganism. Which of the following is not a postulate?
Select one:
a. The pathogen must be found in all cases of disease
b. The pathogens must be cultured outside the host in the laboratory
c. The pathogen must cause disease in a healthy animal
d. The pathogen must be tested in humans to determine whether it causes disease
e. The pathogen should be re-isolated from the test animal
Koch’s postulates are four criteria that are used to determine whether a disease is caused by a particular microorganism. Which of the following is not a postulate?
Select one:
a. The pathogen must be found in all cases of disease
b. The pathogens must be cultured outside the host in the laboratory
c. The pathogen must cause disease in a healthy animal
d. The pathogen must be tested in humans to determine whether it causes disease
e. The pathogen should be re-isolated from the test animal
Definition
an association between two organisms in which one benefits and the other derives neither benefit nor harm
Commensalism
True or False:
It is not possible to become infected with Giardia through contact with blood
True
Cysts form in gut
Define
Lipopolysaccharide (LPS) layer
the major component of the outer membrane of Gram-negative bacteria
Staphylococcus epidermidis is present in all human beings
Select one:
True
False
Staphylococcus epidermidis is present in all human beings
Select one:
True
False
Where does the Plasmodium develop in the mosquito?
The Plasmodium develops in the gut of the mosquito and is passed on in the saliva of an infected infect
Define
Pilin
a class of fibrous proteins that are found in pilus structures in bacteria
Approximately __% of pathogens known to affect humans are zoonotic
Approximately 70% of pathogens known to affect humans are zoonotic
Definition
the infection specificity of certain pathogens to particular hosts and host tissues
Host tropism
Why is Toxoplasmosis particularly dangerous for pregnant women?
Parasites (tachyzoites) can cross the placenta to the foetus
What percentage of microbes are pathogenic?
Less than 5%
Definition
a gram-positive, coagulase-negative cocci that is a part of our skins normal flora
S. epidermidis
Definition
a parasitic flatworm; a tapeworm.
Cestodes
Definition
a toxin that cause host cells to lyse by forming pores in plasma membrane
Membrane-distrupting toxins
Define
Microorganisms
a microscopic organism, especially a bacterium, virus, or fungus.
Define
Periplasmic space
a concentrated gel-like matrix in the space between the inner cytoplasmic membrane and the bacterial outer membrane called the periplasmic space in gram-negative bacteria
Definition
a relict, nonphotosynthetic plastid found in most protozoan parasites belonging to the phylum Apicomplexa
Apicoplast
Draw the Baltimore Classification Scheme diagram
Definition
the complete, infective form of a virus outside a host cell, with a core of RNA and a capsid
Virions
What is a biofilm?
a group of organisms living in a hydrated polymeric matrix
Define
Fungi
any of a group of spore-producing organisms feeding on organic matter, including moulds, yeast, mushrooms, and toadstools
Define
O antigen
an antigen that occurs in the body of a gram-negative bacterial cell
What is the name of an organism that can grow in the presence or absence of oxygen?
Faculative anaerobe
What happens when Plasmodium sporozotes infect humans?
Sporozotes are carried by the blood to the liver where they form cyst-like structures containing thousands of merozoites. After 9-16 days they return to the blood and penetrate the red blood cells, where they multiply again, progressively breaking down the RBCs
How do naked viruses egress?
Lysis
True or False:
The normal flora is well developed in the womb
False
The fetus is sterile in the womb
Definition
a virus which parasitizes a bacterium by infecting it and reproducing inside it
Bacteriophages
Define
Commensalism
an association between two organisms in which one benefits and the other derives neither benefit nor harm
Where are the coat proteins of enveloped and naked viruses found?
Bound to receptors of the capsid of naked viruses and the glycoproteins of enveloped
Definition
a Gram-positive, round-shaped bacterium that is a member of the Firmicutes, and it is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin
S. aureus
Definition
an abnormal form of a normally harmless protein found in the brain that is responsible a variety of fatal neurodegenerative diseases
Prions
Definition
a person or other organism that has become infected with a pathogen, but that displays no signs or symptoms
Asymptomatic carrier
Definition
the period between exposure to an infection and the appearance of the first symptoms
Incubatory
What features fo archaea share with Eukarya?
- DNA replication, transcription and translation seems more like that of Eukarya
- Archaea DNA has histones
- Many enzymes involved in DNA replication are similar to those found in Eukarya
An Asymptomatic carrier is one:
Select one:
a. who harbours the pathogen but does not show any symptoms of the disease
b. who is free of the pathogen
c. who is infected by the pathogen and is in the process of being sick with the disease
d. whose has the antibodies against the disease causing agent
An Asymptomatic carrier is one:
Select one:
a. who harbours the pathogen but does not show any symptoms of the disease
b. who is free of the pathogen
c. who is infected by the pathogen and is in the process of being sick with the disease
d. whose has the antibodies against the disease causing agent
Why do we study viruses?
- Viruses infect all living things
- We eat and breathe billions of virions regularly
- We carry viral genomes as part of our own genetic material
- Viruses drive Global Cycles
What are the four basic shapes of bacteria?
Cocci
Bacilli
Spirochaete
Comma’s
How can Toxoplasmosis alter host behaviour?
Possibly linked to a parasite encoded tyrosine hydroxylase that mimics dopamine and therefore modifies behaviour
Where are extracellular parasites found?
Blood, intestines or genito-urinary system?
Definition
a protein structure found at the base of a eukaryotic undulipodium (cilium or flagellum)
Basal body
Definition
The microorganisms that usually occupy a particular body site
Resident flora
Define
Tissue tropism
the cells and tissues of a host that support growth of a particular virus or bacterium
Define
Exotoxins
a toxin released by a living bacterial cell into its surroundings
Define
Basal body
a protein structure found at the base of a eukaryotic undulipodium (cilium or flagellum)
Attachment or adhesion is mediated by:
1 – capsule
2 – cell wall
3 – cytoplasmic membrane
4 – invasins
5 – fimbriae
6 – ribosomes
Select one:
a. 1 & 6
b. 2 & 4
c. 3 & 5
d. 1 & 5
Attachment or adhesion is mediated by:
1 – capsule
2 – cell wall
3 – cytoplasmic membrane
4 – invasins
5 – fimbriae
6 – ribosomes
Select one:
a. 1 & 6
b. 2 & 4
c. 3 & 5
d. 1 & 5
Definition
a large phylum of parasitic alveolates. Most of them possess a unique form of organelle that comprises a type of plastid called an apicoplast, and an apical complex structure
Apicomplexa
Define
Glycocalyx
a carbohydrate-enriched coating that covers the outside of many eukaryotic cells and prokaryotic cells, particularly bacteria
What is the lifecycle of a hookworm?
Define
Virulence
the severity or harmfulness of a disease or poison
How do enveloped viruses egress?
Budding
Define
Dipicolinic acid
a chemical compound which composes 5% to 15% of the dry weight of bacterial spores. It is implicated as responsible for the heat resistance of the endospore.
Define
Parasitism
relationship between two species of plants or animals in which one benefits at the expense of the other, sometimes without killing the host organism
True or False:
There are no vaccines available for any parasites
True
Define
Yeast
any unicellular fungus that reproduces vegetatively by budding or fission, including forms such as candida that can cause disease
What are the three types of symbiotic bacteria-human relationships?
Mutualism
Commensalism
Parasitism
In what ways do bacteria avoid complement fixation?
Having a capsule - prevents fixation
Secreting complement degrading molecules
Bind antibody by Fc receptor (upside down)
Define
30S ribosome
the smaller subunit of the 70S ribosome found in prokaryotes. It is a complex of the 16S ribosomal RNA (rRNA) and 19 proteins
The resident flora of a person will not cause disease in humans
Select one:
True
False
The resident flora of a person will not cause disease in humans
Select one:
True
False
What are the Molecular Koch’s postulates?
- The virulence gene is always found in strains within a particular virulence phenotype
- The gene should be expressed in the host
- Mutation (inactivation) of that particular gene abolishes the virulence phenotype
- Reintroduction of the gene reconstitutes the virulence phenotype
Definition
Any of a class of proteins associated with the penetration of bacteria into mammalian cells
Invasins
Definition
infection of the intestine with a flagellate protozoan, Giardia, which causes diarrhoea and other symptoms
Giadiasis
Definition
An agent that destroys or causes the expulsion of parasitic intestinal worms.
Anthelminthics
Define
Reverse transcriptase
an enzyme which catalyses the formation of DNA from an RNA template in reverse transcription.
Definition
An enzyme that catalyzes the splitting of a phospholipid molecule by the addition of water
Phospholipases
Define
Acute carrier
an infected individual who is not obviously diseases. Can be incubatory or convalescent
Define
Acid-fast stain
a differential stain used to identify acid-fast organisms such as members of the genus Mycobacterium
What are the two most common bacteria present in all humans?
- Staphylococcus epidermidis*
- Escherichia coli*
Definition
the removal of moisture from something
Dessication
Prions are proteins that cause microbial diseases
Select one:
True
False
Prions are proteins that cause microbial diseases
Select one:
True
False
Define
Comma’s
any curved-rod shaped bacterium
Define
Nematode
a worm of the large phylum Nematoda, such as a roundworm or threadworm
Define
Zoonoses
a disease which can be transmitted to humans from animals
Define
Candida albicans
an opportunistic pathogenic yeast that is a common member of the human gut flora. It can also survive outside the human body. It is detected in the gastrointestinal tract and mouth in 40–60% of healthy adults
Which mechanism is this?
Zipper mechanism
Which mechanism is this?
Trigger mechanism
Describe the life cycle of Giardia
What is the lifecycle of a tapeworm?
