Week 1 Flashcards

1
Q

What is a parasite?

A

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

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2
Q

What is a pathogen?

A

A pathogen is a disease causing organism often used to describe microscopic organisms.

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3
Q

Are pathogens parasites?

A

Yes from an ecological persective are parasites

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4
Q

Name 4 methods of parasite transmission

A

Direct transmisiion–> Air or fluid transfer
Trophic transmission (up the food chain)
Water born transmission
Vector transmission

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5
Q

Variations impacting host infection to parasites

A

Host adaptation
Host specificity
Parasite virulence
Hyerparasites and social parasites

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6
Q

What are hyperparasites?

A

When a parasitic species parasites off another parasitic species

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7
Q

What are the 5 challenges to parasitic lifestyle?

A

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

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8
Q

What factors of the host can impact a major parasite outbreak?

A

Population susceptaibility
Population density
Frequency dependance

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9
Q

What is frequency dependance?

A

The fitness and selection of a population depend on the genetic or phenotypic composition of said population

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10
Q

How does an outbreak impact th long term populaiton of the parasite and host?

A

Major outbreaks on an ecological scale will cause both species to evolve

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11
Q

What are Tinbergens four questions for host organism?

A

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?

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12
Q

What are the 6 types of parasites?

A

Microparasites
Macroparasites
Parasitoids
Endoparasites
Ectoparasites
Social parasites

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13
Q

What are microparasites and what are their key features?

A

Included are viruses, bacteria, fungi and protozoa
Microparasites are small in size typically uo to 200 micrometers in size

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14
Q

What are macroparasites and what are their key features?

A

They include worm like parasites (nemotodes), cestodes), crustacea and insect group
They are group as larger parasites

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15
Q

What are parasitoids?

A

Parasites with a free living stage and parasitic stage, typically the parasitic stage will kill the host. (Parasitic wasps)

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16
Q

What are endoparasites?

A

Parasites that live inside hosts

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17
Q

What are ectoparasites?

A

Parasites that live on the hosts surface

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18
Q

What are social parasites?

A

Parasites that exploit social structures of the host group, these include kleptoparasites and brood parasites.

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19
Q

What does prevalence mean?

A

Number of individual hosts infected within a population

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20
Q

What does intensity mean?

A

Number of parasites in or an a host

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21
Q

What does richness mean?

A

Measure of the number of species of parasite infecting a host

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22
Q

What is an overview of a viruses?

A

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

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23
Q

How does a coronavirus infect a cell?

A

Glycoprotein S on the virus envolope interacts with the cellular receptor ACE2 allowing the virus to enter the cell through endocytosis.

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24
Q

What happens to the virus after it enters the cell?

A

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.

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25
Q

How does the virus genome leave the capsid?

A

Cellular proteases degrade the capsid and the virus genome is left free in the cytoplasm.

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26
Q

What happens to the viral RNA?

A

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.

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27
Q

What happens to the negative sense RNA?

A

The negative sense pre-genomic RNA is then used as a template to replicate the positive sense viral genome.

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28
Q

What happens at the repilcation and transcription site of viruses?

A

The complex synthesized a number of smaller, positive-sense subgenomic RNAs which are then further translated into viral proteins

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29
Q

What happens at the repilcation and transcription site of a virus?

A

The complex synthesized a number of smaller, positive-sense subgenomic RNAs which are then further translated into viral proteins.

30
Q

Where does the viral envelope come from?

A

Endoplasmic reticulum –> the viral envolope comes from the endoplasmic reticulum membrane

31
Q

What is and what happens in the final stage of viral formation?

A

Maturation
Using viral protease all the components of the virus fit together and the particle becomes infectious

32
Q

What are retroviruses?

A

A virus that converts the viral RNA into DNA. They are related to reverse transcribing elements.

33
Q

What are retrotransposons?

A

Retrootransposons copy and past themselves into different genomic locations by converting RNA back into DNA through a process called RNA transposition intermidiate. These degrade overtime

34
Q

Where do archaea live?

A

Inhibit extreme environments

35
Q

How similar to bacteria are archaea?

A

They resemeble bacteria morphology but have very different genetic and biochemical level

36
Q

Are archaea parasitic?

A

No known cases - often mutalists or commenslas

37
Q

What are the key traits of bacteria?

A

Rapid evolution
Infect all other organism except viruses
Some are able to form spores and persist for long periods

38
Q

What is a common way to seperate and idenitfy bacteria?

A

Gram positive and gram negative

39
Q

What are key physical traist of Bascillus anthracis?

A

They are rod shaped and gram positive

40
Q

What is a key trait of the spores of Bascillus anthracis?

A

They are highly resistant, resiting heat, desiccation, UV and gamma radiation. They can persist for years.

41
Q

Who is usually infected with anthrax?

A

Large herbivoures but can infect almost any animal

42
Q

What happens when an animal is infected with Bascillus anthracis?

A

First introduced as a spore with with a capsule and a pilli
The spores activates when in a host macrophate lysing the host cells, invading hoss lymph nodes and moving into the blood stream.

43
Q

What happens in a late stage infection of Bascillus anthracis?

A

The host will bleed through the nose, mouth and bowel with blood introducing vegetative (active) bacteria to the surrounding soil.

44
Q

What causes a Bascillus anthracis spore to form?

A

They form when vegetative bacteria are exposed to oxygen, only taken when resources are scarce due to it being a taxing process.

45
Q

When was gruinard island contaminated?

A

1942 in order to induce pulmonary anthrax in sheep

46
Q

How was gruinard island decontaminated?

A

In the 1980s 280 tons of formaldehyde and seawater were sprayed and topsoil was removed. Restrictions lifted in 1990 as sheep grazed there successfully

47
Q

What are protazoa?

A

Small single celled eukaryotes
Mostly free living but some are parasites

48
Q

How do protazoa feed?

A

Some by phagotropy (engulfing food particulates)
Some by saprozoicly (eating dead matter)

49
Q

Do protozoa form cysts?

A

Many form cysts in tough conditions or as a transmission stage

50
Q

What are the main subphyla of protozoa?

A

Mastigophora –> trypanosomes
Sarcodina –> Amoebas
Sporozoa –> Plasmodium
Ciliophora –> Ichthyophthiris multifiiliss (Ich)

51
Q

What are the 3 life stages of Ich?

A

Trophont –> feeding on fish encysted between layers of skin and gills
Tomont –> Leaves the fish and starts reproducing in the environment. It secretes an outer cyst that sticks to a surface and begins to devide.
Theront –> Bore out of the cyst and become free swimming, infective and fish seeking parasites - treatments often target this stage

52
Q

What are the main four phyla of fungi?

A

Chytridiomycota, Zygomycota, Ascomycota and Basidiomycota

53
Q

Which groups of fungi are parasites found?

A

All of them

54
Q

Name a fungus is parasitic and commercially important?

A

Powdery mildew

55
Q

Name a fungi are oppotunistic pathogen?

A

Candida

56
Q

What are the 4 stages of the Zombie ant fungus (Ophiocordyceps Unilateralis)?

A

Infection - spores land on the ant and excrete an enzyme that cuts through the exterior shell
Biting - After 2 days the ant climbs to a spot with optimal temperature and humidity on a stalk or the bottom of a leaf and bites into the middle vein then dies.
Growth - the fungus consumes the ants internal organs the stroma erupts from the head of the ant
Dispersal - spores emitted from the stroma, float down and infect new ants

57
Q

What rough percentage of plants are parasitic?

A

1%

58
Q

Can parasitic plants do photosynthesis?

A

Some can and some rely entirely on their host

59
Q

What is the name of the structure used to syphon nutrients from other plants?

A

Haustrorium is used to penetrate the host plant

60
Q

What are example of parasitic plants?

A

Mistletoe, ghost plant (Monotropa uniflora) and giant padma (Rafflesia arnoldii)

61
Q

What are the 4 main groups of eukaryotic parasites?

A

Nematodes
Helminths - not an official taxon but includes Turbellaria, trematodes and cestodes
Acanthocephala - entirely parasitic group of species, denoted by the large proboscis
Annelida - both free living parasitic, leeches are the most famous ecample

62
Q

What is the lifecycle of the nematode Drucunculis medinensis?

A

Person drinks water with copepods infected with L3 larvae
The larvae are released when copepods die, they then penetrate the hosts stomach and intestinal wall which they then mature and reproduce
A fertilised female worm migrates to the skins surface causing a blister and discharges larvae
Larvae released unto water by emerging female worm, typically 1 year after initial infection
The larvae are consumed by copepods. which then undergoes 2 molts to become L3 larvae

63
Q

Life cycle of the cestode, tape worm?

A

Eggs are passed in feces
They are eaten by an athropod
Oncospheres hatch and penetrate the intestinal wall
Cysteicerci in body cavity of insects ingetsed by rodent or human
Adults then live in the small intestine where they reproduce and release eggs which pooed out

64
Q

What is the lifecycle of an acanthocephalan (Rotifera)?

A

Female releases eggs which when fertalized seek to be ingested by an intermidiate host
They pierce the haemocoel and become encysted
Once intermediate is eaten by the desired final host they mature
No digestive tract, nutrients are absorbed through the skin

65
Q

Can Crustacea be parasitic?

A

Yes

66
Q

Name some parasitic crustaceans?

A

Pentastomatida
Copepoda (fish lice)
Isopoda
Rhizaocephale (parasitic barnacles)

67
Q

What are key features of mites and ticks

A

Typically ectoparasites
For some it is unlcear if they are parasitic, commensal or phoretic
Many act as vectors for microbial parasites (like Borrelia burgdorferi - Lyme disease)

68
Q

Name a example of social parasites?

A

Cuckoo and cowbird, get chicks raised by other birds

69
Q

Name parasitic insecta?

A

Lice, leaf minors, gall forming insects, some moths and butterflies, strepsiptera and parasitoid species

70
Q

Which insects groups are parasitoids?

A

Mostly hymenoptera and diptera but examples also found in other groups