Week 1 Flashcards
What is a parasite?
Parasites that live in or on another organism in which it increases its own fitness by takng resources at the expennse of the host organism
What is a pathogen?
A pathogen is a disease causing organism often used to describe microscopic organisms.
Are pathogens parasites?
Yes from an ecological persective are parasites
Name 4 methods of parasite transmission
Direct transmisiion–> Air or fluid transfer
Trophic transmission (up the food chain)
Water born transmission
Vector transmission
Variations impacting host infection to parasites
Host adaptation
Host specificity
Parasite virulence
Hyerparasites and social parasites
What are hyperparasites?
When a parasitic species parasites off another parasitic species
What are the 5 challenges to parasitic lifestyle?
Finding a host
Navigating through the host to find the required region or organ
Avoiding the defences of the host
Finding a mate or undergoing a means of reproduction
Dispese to find new hosts
What factors of the host can impact a major parasite outbreak?
Population susceptaibility
Population density
Frequency dependance
What is frequency dependance?
The fitness and selection of a population depend on the genetic or phenotypic composition of said population
How does an outbreak impact th long term populaiton of the parasite and host?
Major outbreaks on an ecological scale will cause both species to evolve
What are Tinbergens four questions for host organism?
Causation - how does immunity work physiologically
Developement - is immunity genetically encoded or does environement play a role? Does it change during developement?
Evolution - how does immunity arise in the species?
Function why is this adaptive for the species?
What are the 6 types of parasites?
Microparasites
Macroparasites
Parasitoids
Endoparasites
Ectoparasites
Social parasites
What are microparasites and what are their key features?
Included are viruses, bacteria, fungi and protozoa
Microparasites are small in size typically uo to 200 micrometers in size
What are macroparasites and what are their key features?
They include worm like parasites (nemotodes), cestodes), crustacea and insect group
They are group as larger parasites
What are parasitoids?
Parasites with a free living stage and parasitic stage, typically the parasitic stage will kill the host. (Parasitic wasps)
What are endoparasites?
Parasites that live inside hosts
What are ectoparasites?
Parasites that live on the hosts surface
What are social parasites?
Parasites that exploit social structures of the host group, these include kleptoparasites and brood parasites.
What does prevalence mean?
Number of individual hosts infected within a population
What does intensity mean?
Number of parasites in or an a host
What does richness mean?
Measure of the number of species of parasite infecting a host
What is an overview of a viruses?
No metabolism so explot host cell
All are symbiotic or parasitic
Follow the stages of attatchment, enter and hijacking of cellular machinary
Viruses are distinguished by their capsid
How does a coronavirus infect a cell?
Glycoprotein S on the virus envolope interacts with the cellular receptor ACE2 allowing the virus to enter the cell through endocytosis.
What happens to the virus after it enters the cell?
The virus causes a lysosome mediated pH drop causing the fusion between the viral membrane and the endosome (lipid membrane that surrounding virus as it enters). This causes the capsid to be released into the cell.
How does the virus genome leave the capsid?
Cellular proteases degrade the capsid and the virus genome is left free in the cytoplasm.
What happens to the viral RNA?
As the RNA is positive sense it serves as a template to directly translate into the polyproteins. These proteins are processed forming the replication and transcription complex.
What happens to the negative sense RNA?
The negative sense pre-genomic RNA is then used as a template to replicate the positive sense viral genome.
What happens at the repilcation and transcription site of viruses?
The complex synthesized a number of smaller, positive-sense subgenomic RNAs which are then further translated into viral proteins