Topics 1 - 3

Question 1

Mutualism w/ example

Answer 1

Benefit from coexistence without losing the ability to live independently
eg. clownfish seek protection from anemone, whilst attracting prey for anemone and proving nutrients in form of waste.

Question 2

Symbiosis w/ example

Answer 2

Different organisms rely on coexistence - viability reduced when separated
eg. Lichen formed by the symbiosis of fungi and algae

Question 3

Commensalism w/ example

Answer 3

One partner benefits without reciprocating benefit, nor causing harm/cost to host, often for food or shelter.
eg. pearlfish seeking protection in sea cucumber

Question 4

Heterospecific parasite relationship

Answer 4

Parasitic interactions between organisms of different species.
i.e. Mother and fetus not parasitic

Question 5

Parasite vs pathogen

Answer 5

Parasitism typically occurs within kingdoms

i.e. E. coli infecting humans is pathogenic, not parasitic.

Question 6

Parasitoidism w/ example

Answer 6

Death of host following parasitic exploitation - often for host consumption.
eg. Ichneumon wasps laying eggs on caterpillar, larvae feed on host.

Question 7

Predatory/prey w/ example

Answer 7

Host (prey) is immediately killed then eaten.

eg. lion and antelope

Question 8

Parasitism w/ example

Answer 8

guest organism extracts nutrients from host AND incurs cost from relationship. Sustained relationship for benefit of parasite.
eg. toxoplasma in felids

Question 9

Two subtypes of parasitism w/ example

Answer 9

1. Brood: organisms that rely on others to raise their young.
   eg. cuckoo bees laying eggs near nest of other bees so their larvae to ‘steal’ other nests food.
2. Phoresy: non-permenant commensalism where parasite uses another organism for transport.
   eg. sexton beetle mites uses beetle for transport between cattle.

Question 10

Obligate vs facultative parasite

Answer 10

Obligate parasite requires host to complete life cycle. Facultative can choose to adopt parasitic lifestyle, but can live independently.

Question 11

4 things that make a successful parasite

Answer 11

1. mechanism of invasion
2. evade host immunity
3. mechanism of transmission
4. ensures survival of host

Question 12

Definitive host

Answer 12

Host in which parasite sexually matures

Question 13

Intermediate host

Answer 13

host in which parasite undergoes required developmental stage. (sometimes asexual reproduction)

Question 14

Accidental host

Answer 14

host that normally isn’t apart of parasite lifecycle. May be dead end

Question 15

Paratenic host

Answer 15

Transports parasite, not required for life cycle

Question 16

Reservoir host

Answer 16

host that maintains parasite population. Has the potential to transmit to humans and domestic animals.

Question 17

3 groups of parasites

Answer 17

1. protozoa (unicellular)
2. arthropods (invertebrates)
3. helminths (worms)

Question 18

Where Malaria is most prevalent

Answer 18

Sub-saharan Africa, latin america, east asia

Question 19

Cell recognition via Duffy

Answer 19

Duffy Binding Protein (DBP) ligand on P. vivax surface interacts with Duffy Antigen Receptor (DARC) on RBC surface.

Question 20

Intracellular parasitism benefits

Answer 20

1. protections (host defence, enviro stress)
2. accessible nutrients
3. transport / disperal
4. manipulate host cell metabolism
5. manipulate host cell response

Question 21

Intracellular parasitism challenges

Answer 21

1. invasion and egress between host cells
2. invasion and egress between host organisms
3. sustaining host
4. evade host immunity and cell defence
5. acquiring apropriate and sufficient nutrients

Question 22

Mechanisms of invasion

Answer 22

active = use of own machinery
passive = exploiting host machinery

Question 23

Apicomplexan structures: Hardware mobility

Answer 23

• Micro.T
• inner membrane complex
• apical ring (w/ apical complex / MTOC)

Question 24

Apicomplexan structures: Metabolic organelles

Answer 24

• Nucleus
• mitochondria
• apicoplast

Question 25

Apicomplexan structures: Secretory organelles

Answer 25

• Rhoptries (secreted into host)
• micronemes (secreted into parasites own p.membrane)
• dense granules

all play a role in invasion

Question 26

Methods of localisation

Answer 26

1. live cell imaging
2. dissecting targeting signals
3. IFA
4. Co-IP ?

Question 27

Methods of ‘is it essential?’

Answer 27

1. Knockout
2. regulatable knockout
3. transcriptional regulation
4. post-transcriptional regulation
5. post-translational / protein regulation