Viruses Flashcards
Which virus causes Chickenpox?
Varicella Zoster Virus (VZV)
Which virus causes Shingles?
Varicella Zoster Virus (VZV)
What is Herpes Zoster another word for?
Shingles
What is the active form of acyclovir?
Acycloguanosine triose phosphate (acyclo GTP)
Acyclovir derives from which compound?
Deoxyguanosine
Deoxyguanosine is changed to acyclovir by which chemical?
Thymidine Kinase
Name x3 viruses Acyclovir can be used to treat
Herpes Simplex virus,
Epstein Barr virus +
Varicella Zoster virus
What is the difference between a nucleotide and a nucleoside?
Nucleosides only possess a sugar and a base in their structure. There is no phosphate group.
What is the name for the nucleoside of adenine?
Adenosine deoxyadenosine
What is the name for the nucleotide of adenine?
Adenylate deoxyadenylate
Define latency
The ability to induce life-long infection in a host cell
What is the group name of drugs Acyclovir falls under?
Nucleoside analogues
Name two mechanisms by which resistance to acyclovir can occur
Viral Thymidine kinase mutation
Viral DNA polymerase mutation
What does Acyclovir do?
Inhibits DNA replication
Name x3 Gram positive bacteria
Staphylococcus aureus, streptococcus pneumoniae and streptococcus pyogenes
Name x3 Gram negative bacteria
Escheria Coli, Vibrio Cholerae and Shigella
Name two intracellular bacteria
Shigella, Salmonella
Name three extracellular bacteria
Streptococcus, staphylococcus and neisseria
What are the three methods for horizontal gene transfer?
Conjugation, Transduction and Transformation
What are two differences between gram positive and gram negative bacteria?
Gram positive bacteria stains purple whereas gram negative bacteria stains pink. Gram negative bacteria have an additional membrane with a thinner peptidoglycan layer.
What causes the pink staining in gram negative bacteria?
Gram negative bacteria has a thinner peptidoglycan structure meaning that dye is lost.
Where is staphylococcus aureus often found?
In the nasal cavity and skin
Where is the streptococcus species often found?
In the mouth
Where is Streptococcus group B found?
In the small/large intestine and genital tract
Name x3 microbes found in the small/ large intestine
Escheria Coli, Candida and Streptococcus group B
Name a commensal bacteria
Lactobacillus
Name x3 points of entry for bacteria
- Upper respiratory tract
- Urogenital tract
- Gastro-intestinal tract
Name x2 upper respiratory tract infections
Tonsillitis, sinusitis
Name x2 lower respiratory tract infections
Pneumonia, bronchitis
Define Sepsis
Organ dysfunction in response to an infection
Name x3 bacteria causing infection in the gastro-intestinal tract
Salmonella typhi, Shigella and Escheria Coli
Name an example of an opportunistic bacteria
Staphylococcus epidermidis
What is virulence?
Features that enhance disease causation
Name x5 things that can affect pathogenicity
- Transmission to host
- Replication rate
- Toxin production
- Tropism
- Ability to colonise
What does a low infectious dose mean?
A lower average amount of bacteria are needed to cause disease e.g. Mycobacterium tuberculosis
What bacteria causes tonsillitis?
Streptococcus pyogenes
Name an infection with a high infectious dose
Vibrio Cholerae
Describe a virulence mechanism by staphylococcus aureus
Staphylococcus aureus makes leukocidins which makes holes in host neutrophils and cause neutrophil death
What is pus made up of?
Dead neutrophils
What shape bacteria are E.coli, salmonella and shigella?
Gram negative Bacilli shapes (rods)
Do opportunistic bacteria have high or low virulence?
Low virulence
How does the injectisome work?
The injectisome allows virulence proteins to move into the cell via the translocase complex. The injectisome causes polymerisation of the actin cytoskeleton and membrane ruffling = allows bacteria in.
What are pathogenicity islands?
DNA which codes for proteins contributing to virulence by making injectisomes or toxins.
How can antibiotics be harmful to normal flora?
Antibiotics can kill commensal flora which usually serves as competition for pathogens. This allows pathogens to grow and produce toxins.
What are protozoa?
Single celled eukaryotes.
Are bacteria eukaryotes or prokaryotes?
Prokaryotes.
Are viruses prokaryotes or eukaryotes?
NEITHER.
HIV, SARS and Influenza are all examples of what?
Viruses; obligate and not free-living.
x2 differences between viruses and bacteria
Virus = plasmid and no organelles. Bacteria = linear DNA + organelles.
Candida albicans is under what class group?
Fungi
