Lecture 10 (part 2 only)

Question 1

Name the 5 bacteria involved in the sulfur cycle

Answer 1

1) Alteromonas
2) Desulfovibrio
3) Thiobacillus
4) Thiothrix
5) Thiomargarita

Question 2

1) What is a major source of sulfate?
2) Where is sulfur found?
3) What is sulfur reduced by and what is it reused in?

Answer 2

1) The weathering of rocks is a major source of sulfate
2) In fossil fuels, vegetables, etc.
3) Reduced by plants and microbes and reused in proteins, coenzymes, bridging ligands, and amino acids.

Question 3

1) Is sulfur needed for life? Does it make up a large amount of biomass?
2) Is sulfur easy to process?
3) Where are large sulfur deposits found?

Answer 3

1) Needed for life but only a small fraction of biomass.
2) Organisms have difficulty processing sulfur.
3) Underground.

Question 4

What part of the sulfur cycle is a regulator of the global climate? How?

Answer 4

Atmospheric sulfate in the air is a regulator of the global climate; helps create cloud cover that cools cities and can help with global worming.

Question 5

1) List 4 things involved in the sulfur cycle
2) What does Thiobacillus do? What does it require?

Answer 5

1) Sulfite, sulfate, elemental sulfur, hydrogen sulfide
2) Produces sulfate from elemental sulfur; requires nitrogen

Question 6

Name 2 things that contribute sulfur. Include what form they contribute sulfur in.

Answer 6

1) Volcanoes (SO2)
2) Deep sea vents (H2S)

Question 7

Describe the roles of algae, the continental shelf, and hydrothermal vents in the sulfur cycle

Answer 7

1) Algae: metabolize sulfate which produces DMSP. Many microbes can utilize DMSP to make MESH, DMS (highly reactive and escape into atmosphere)
2) Continental shelf: H2S can be re-oxidized by Thiomargarita
3) Hydrothermal vents: sulfate precipitates out of the sea water (CaSO4); lots of H2S. Allows for ecosystems to form around the vents.

Question 8

Lots of _______ and _________ have evolved to contribute to the sulfur cycle

Answer 8

bacteria and archaea

Question 9

1) What is the phosphorus cycle required for?
2) What plays a large role in the phosphorus cycle?
3) Where is phosphorus found? Where is it used?

Answer 9

1) Required for nucleic acids, lipids, some polysaccharides.
2) pH plays a large role in the form of phosphate
3) Found in rocks and bird poop. Used in fertilizer.

Question 10

1) Does the phosphorus cycle have a gaseous component?
2) In which 3 places does phosphorus collect?
3) What does the phosphorus cycle form?
4) Organic matter is broken down into what?

Answer 10

1) No gaseous component, so it collects
2) In the sea, in the earth, in calcium phosphate deposits,
3) Forms insoluble complexes and go into water sources.
4) Organic matter is broken down into elemental phosphorus to enter the cycle.

Question 11

Name the bacteria that is involved in all 3 cycles (nitrogen, sulfur, phosphorus) and describe its role in the phosphorus cycle

Answer 11

Thiobacillus produces an acid that causes phosphate to be released

Question 12

Define bioremediation, biosensors, and exposing coliforms.

Answer 12

1) Bioremediation: The use of microbes to detoxify or degrade pollutants
2) Biosensors: Microbes can locate biologically active pollutants (by exposing the presence of a chemical). Bioluminescence can be used to detect (ex: TNT).
3) Exposing coliforms: ONPG + MUG

Question 13

List and describe the 4 steps of water treatment

Answer 13

1) Water is held in reservoir, particles settle
2) Flocculation: Removal of colloidal materials (aggregates)
Flocculant: Aggregates materials (ex: Al, Fe, C, Mg)
3) Filtration: 2-4 feet of fine sand or anthracite coal. Eliminates almost all potentially harmful bacteria.
4) Ozone treatment: Disinfecting the water using UV + electricity = O3 (highly reactive) or chlorination. Ozonation leaves no taste or odor.
5) Water is stored and used by consumers

Question 14

Define the following:
1) Mutualism
2) Cooperation
3) Commensalism
4) Predation

Answer 14

1) Mutualism: Both organisms benefit; obligatory
2) Cooperation: Both organisms benefit, not obligatory
3) Commensalism: One helps the other.
4) Predation: One benefits, one is harmed

Question 15

Define the following:
1) Parasitism
2) Amensalism
3) Competition

Answer 15

1) Parasitism: Parasite lives in host
2) Amensalism: One hurts the other
3) Competition: One outcompetes the other or both coexist at lower levels

Question 16

1) What is trichonympha and what does it do?
2) What lives inside trichonympha and what does it do?
3) What do they both produce?

Answer 16

1) A protozoan that lives inside a termite gut that breaks down cellulose from wood.
2) TG1 lives inside the protozoan that converts glutamine and ammonia into amino acids and cofactors that can be broken down.
3) Both produce CO2 and many of these terminal products can be used by the host termite.

Question 17

1) Give 2 examples of cooperation
2) Give an example of am

Answer 17

1) a) Chromatium converts light into SO4-2 and OM, which is converted by Desulfovibrio into CO2 and H2S.
b) Cellulomonas (cellulose degrader) converts NH4+ onto glucose, which is converted from N2 by azotobacter (nitrogen fixer)
2) Amensalism: Attine ant cultivates a fungal garden; the parasite on the fungal garden of an ant is kept at bay because of the relationship between the ant and Pseudonocardia (which controls the parasite)