7 - Amoebae

Question 1

Give the main features of Amoebae

Answer 1

They have one macronucleus, most are aerobic, most are heterotrophic (some are mixotrophic) and the only reproduce asexually over no soecific plane

Question 2

How do naked Amoebae move?

Answer 2

Via cytoplasmic streaming (often using pseudopodia)

Question 3

How do naked Amoebae feed?

Answer 3

Via raptorial feeding, with no specific location for ingestion

Question 4

What are the three forms of naked amoebae?

Answer 4

Trophozoites - the feeding form (blob form)
Cysts
Floating form - stiffened pseudopodia for dispersal (can’t feed - transport form)

Question 5

What are the four types of shelled amoebae and how do they feed?

Answer 5

Testate amoebae - raptorial
Foraminiferans - diffusion
Radiolarians - diffusion
Heliozoans - diffusion

Question 6

How does diffusion feeding work?

Answer 6

Sticky parts of extrashellular cytoplasm (axopodia) capture prey and the prey then diffuses into the cytoplasm

Question 7

What type of protist are ‘bad’ and why

Answer 7

Mainly amoebae and they allow the evolution of bacterial pathogens and act as a reservoir

Question 8

What nutrients do photoautotrophs release and who do they help?

Answer 8

They release dissolved organic sugars (sugars) that are absorbed by bacteria.

Question 9

What do heterotrophic Protozoa release and who absorbs it

Answer 9

Nitrogen and phosphorus which is absorbed by bacteria and photoautotrophic protists

Question 10

Why do protists loose such much nitrogen and phosphorus

Answer 10

They have to maintain the ratio of carbon:nitrogen:phosphorus, so when they loose carbon dioxide in respiration they have to pump out nitrogen and phosphorus to maintain the ratio

Question 11

How do amoebae help bacteria practice evading our immune system?

Answer 11

Naked Amoebae are very similar to macrophages, so they practice evading digestion in amoebae, making them more pathogenic

Question 12

Why do some amoebae get called ‘Trojan horse’

Answer 12

They can contain thousands of pathogenic bacteria

Question 13

How is Legionella transmitted and what is it’s reservoir?

Answer 13

It is transmitted by air and water (often inhalation of water droplets) and it’s reservoir is amoebae

Question 14

How do amoebae help bacterial growth

Answer 14

They predate them which keeps them in the log phase, preventing them from reaching the stationary phase and keeps them active

Question 15

What protists cause dysentery?

Answer 15

Amoebae (such as entamoeba histolytica), balantidium coli (ciliate) and flagellates (such as giardia lamblia)

Question 16

what is the reservoir for dysentery?

Answer 16

Water and animals/humans

Question 17

How is dysentery transmitted?

Answer 17

Via Contaminated water or via the faecal-oral route

Question 18

What protist causes keratitis, what is it’s reservoir and how is it transported?

Answer 18

It is caused by amoebae from acanthamoeba, it’s reservoir is water and it is transmitted by dirty contact lenses

Question 19

What causes primary ameobic meningioencephalitis, what is it’s reservoir and how is it transmitted?

Answer 19

It is caused by naegleria fowleri amoeba. It’s reservoir is warm water and it’s transmitted by the flagellate swimming up the nose.

Question 20

What protist causes trichomoniasis, what is it’s reservoir and how is it transmitted?

Answer 20

It’s caused by the flagellate trichomonas vaginalis, it’s reservoir is humans (particularly males as they are asymptotic) and it is transmitted by sexual intercourse

Question 21

What protist causes leishmaniasis, what is it’s reservoir and how is it transmitted?

Answer 21

It’s caused by leishmania mexicana, it’s reservoir is dogs and it is transmitted by a sand fly vector