Inter-microbial relationships

Question 0

What happens if there are negative interactions between inter microbial relationships?

Answer 0

This limits the population density and can eliminate the population

Question 1

Why are positive interactions in inter microbial relationships important?

Answer 1

Because it enhances the survival capacity of population

Question 2

When will neutral interactions occur in inter microbial relationships?

Answer 2

Most likely at a low population density

Question 3

What is commensalism?

Answer 3

One symbiont (commensal) benefits, other (host) neither harmed or helped; association not obligatory

Question 4

Give an example of a commensal relationship

Answer 4

Staphylococcus on skin

Question 5

What is cooperation?

Answer 5

Both populations benefit; association not obligatory

Question 6

Give an example of a cooperative relationship

Answer 6

E. Coli in the gut

Question 7

What are commensalism and cooperation also examples of?

Answer 7

Syntrophism

Question 8

What is mutualism?

Answer 8

Symbionts metabolically dependent upon each other. Benefits both mutualism and host; obligatory relationship

Question 9

Give an example of a mutualistic relationship

Answer 9

Tube worms and sulphide-oxidising bacteria.
Life at 2.5km below sea surface on hydrothermal vents. Bacteria are primary producers for the whole community and tube worms are supported by endosymbiotic bacteria which obtain energy from H2S oxidation. Reduced organic material thats produced from inorganic substances serves as tube worm nutrient source

Question 10

What are endosymbionts and give and example

Answer 10

Bacteria obligately living within cells (e.g tube worm - bacteria maintained in specialised cells)

Question 11

What is the endosymbiotic theory?

Answer 11

Organelles of eukaryotic cells arose from prokaryotic cells that developed symbiotic relationship with eukaryote to be

Question 12

Explain nitrogen- fixing symbiosis

Answer 12

Rhizobium and bradyrhizobium have a symbiotic relationship with leguminous plants and only fix nitrogen when in the root nodule. Bacteria gain organic nutrients from plant and oxygen from plant leghaemoglobin and plants benefit by gaining nitrogen

Question 13

What is a rumen ecosystem?

Answer 13

Mixed microbial populations in rumen of herbivores; mutualistic population.
Microbes degrade cellulose, starch, pectin to low molecular weight organic acids which is then energy source for ruminants (herbivores)

Question 14

What is bioluminescence?

Answer 14

Mutualism between bacteria and fish. Light is produced by the bacteria and fish maintain bacteria in light organs so fish can signal or hunt prey

Question 15

What is controlled parasitism?

Answer 15

Example of this is lichens. They are a heterotrophic fungus and cynobacterium.
Fungus produces organic acids that solubilise rock minerals am obtains oxygen and nutrients from partner.
Cynobacterium is photosynthetic and may fix nitrogen. Is protected from excess light intensities and obtains water and minerals from partner

Question 16

What is amensalism?

Answer 16

Release of a specific compound by one organism which has a negative effect on another organism

Question 17

What is predation?

Answer 17

Predator attacks or engulfs prey