Lecture 4 Flashcards
How are fungi different from plants and animals?
Fungi have cell walls and do not use photosynthesis
How are fungi different from plants and animals?
Fungi have cell walls and do not use photosynthesis
How do yeasts differ from moulds?
Yeasts are unicellular and moulds are multicellular and made of hyphae
What is a dimorphic fungus?
A fungus that changes morphology depending on its environment. Can be yeast or mycelial.
What media is used for growing fungi?
a. Sabouraud’s agar
i. High sugar concentration
ii. Acidic pH
iii. Antibiotics - suppress bacterial growth
Why are oranges spoilt by mould rather than bacteria?
a. The acidic environment is good for fungi growth and poor for bacterial growth.
List the types of asexual spores of fungi.
a. Sporangiospores
b. Chlamydospores
c. Conidiospores
d. Arthrospores
e. Blastospores
List the four stages of fungal sexual spore formation.
a. Cells of +thallus and -thallus fuse
b. Nuclei fuse
c. Meiosis of nucleus restores haploid state
d. Haploid nucleus partitioned into + and - spores
List three types of fungal sexual spores.
a. Zygomycota
b. Basidiomycota
c. Ascomycota
What type of fungi cause tinea?
a. Trichophytin rubrum.
b. Microsporum canis.
Systematic mycoses are caused by which fungi?
a. Histoplasma
b. Blastomyces
c. Coccidioides
d. Paracoccidioides
Which fungi cause thrush?
a. Candida
Mycotoxins contaminate approximately 25% of foods worldwide, however usually do not cause disease, why?
a. The concentration is not high enough to cause disease.
Why can’t viruses be grown on artificial media?
Viruses require a host cell in order to replicate, media is not a host cell.
What is the main feature of viruses that is used to classify them?
Nucleic acid
List the Baltimore classification of viruses.
a. Class 1: double stranded DNA (ds DNA)
b. Class 2: single stranded DNA (ss DNA)
c. Class 3: double stranded segmented RNA (dsRNA)
d. Class 4: single stranded RNA (ss RNA) positive sense
e. Class 5: single stranded RNA (ss RNA) negative sense
f. Class 6: ss RNA positive sense with ds DNA intermediate before replication (retroviruses)
g. Class 7: ds DNA with positive sense, part ss DNA, with ss RNA intermediate (reversiviruses)
What are the three morphological types of viruses?
a. Helical
b. Icosahedral
c. Complex
What are two ways that viruses can cause disease?
a. The immune system attacks the infected cells and destroys them in the process
b. Virus destroys the cell through replication
List the stages of viral infectivity.
Mild Latent Severe Chronic Oncogenic Teratogenic
List the viral replication stages.
a. Attachment
b. Penetration
c. Replication of viral genome
d. Production of late viral proteins
e. Assembly of progeny virions
f. Release of virions from cell (budding or lysis)
List two modes of transmission of viruses.
a. Physical contact
b. Air-borne
What are viruses that infect bacteria called?
Bacteriophage
What are the names for round and flat worms?
a. Nematodes (round worms)
b. Platyhelminths (flat worms)
Liver flukes establish infections in what part of the body?
Bile Duct and feeds on the liver
What is the common name for cestodia?
Tape worms
Why are nematode infections so common?
Most commonly transferred with faecal oral transmission via water.
What are the symptoms of Malaria and why do these symptoms occur?
a. Sudden fever, chills, nausea and headache.
i. They are caused from the sudden lysis (bursting) of infected red blood cells
What is the main route of infection for parasites? What is an exception?
a. Attach into the small intestine and absorb nutrients from chyme passing through.
i. Malaria instead attached to red blood cells and replicates until they go through lysis.
Ascaris lumbricoides, Trichuris trichiura and Enterobius vermicularis are what type of helminth?
Nematode (round worm)
