Microbial ecology

Question 1

Ectosymbiont

Answer 1

1 M located on surface of larger m

Question 2

Endosymbiont

Answer 2

M lives inside another M

Question 3

Consortium

Answer 3

-Physical association of two different organisms, usually beneficial to both
-Complimentary physiological properties
-benefit of all organisms interactions

Question 4

Types of association

Answer 4

-Intermittent: Legionellosis + people
- Permanent: heterorhabditis and Photorhabdus

Question 5

Protocooperation

Answer 5

Mutually beneficial but not needed for survival (not obligatory)

Question 6

Protocooperation Eg

Answer 6

Desulfovibrio
-anaerobic
-uses sulfate as e acceptor
-produces CO2 and H2S
Chromatium
-Photosynthetic
-Fixes CO2 to produce OM and sulfate from light

If seperated they can get nutrients from environment

Cellulose degrader (Cellulomonas) produces glucose for Nitrogen fixer (Azotobacter) which produces NH4+

Question 7

Commensalism

Answer 7

One benefit, one neither is affected
-usually 1, benefits from waste products of other
-When separated one wouldn’t know and the other would grow slower

Question 8

E.Commensalism

Answer 8

Examples: Nitrosomonas(produce nitrite) and Nitrobacter (uses waste product to oxidise nitrate to produce nitrate)

Question 9

Predation and parasitism

Answer 9

One species increases population at expense of pop of other species
-engulfs or attacks

Question 10

Amensalism

Answer 10

Products of one has negative affect on another
-Unidirectional and specific compounds
-Bacteriosomes: small peptides used by B to attack other B

Question 11

Competition

Answer 11

Different B -> same resource
-One outcompetes the other for the site’s resource
-B grows slower and has smaller pop size

Question 12

Mutualism

Answer 12

Reciprocal positive effect to both organisms
-Obligatory

Question 13

E. Mutualism

Answer 13

• Riftia
  Lichens:
  -Mycobiont: Ascomycetes fungi (Protect other from excess light, substrate to attach to and minerals)
  -Photobiont: Cytobacterium: provides O2 and organic carbon

Question 14

deep-sea hydrothermal vents

Answer 14

Occurs where sea floor cracks which cause heated sea water due to magma which forms a hydrothermal vent
Vent releases chemically modified sea water

Question 15

Sulphide-based mutualism

Answer 15

-Hydrothermal vents
-Vent fluid:
* Temperature: High temp from 2C->10C->20C at a distance away from vent
*H2S
*Riftia pachyptila: also caled giant red gutless tube worm

Question 16

Riftia pachyptila mechanism

Answer 16

Red gutless worm
- + for B:
*Protective B
*Gets nutrients (H2S and O2)
*Very high concentration compared to ocean water
Evolutionary: dedicated evolutionary housing endosymbiotic B: nutrients get transported from trophosome (organic matter through oxidation)