Why is the phosphorus cycle important?

In the sulfur cycle, microbes degrade organic sulfur compounds, such as (a) _________________, to release H₂S, which can be oxidized by Acidithiobacillus to (b) _________________. This ion can be assimilated into amino acids by (c) _________________ or reduced by Desulfovibrio to (d) _________________. H₂S is used by photoautotrophic bacteria as an electron donor to synthesize (e) _________________. The sulfur-containing by-product of this metabolism is (f) _________________.

For the following question, answer whether

a. The process takes place under aerobic conditions.

b. The process takes place under anaerobic conditions.

c. The amount of oxygen doesn’t make any difference.

Methane production

For the following question, answer whether

a. The process takes place under aerobic conditions.

b. The process takes place under anaerobic conditions.

c. The amount of oxygen doesn’t make any difference.

Denitrification

The water used to prepare intravenous solutions in a hospital contained endotoxins. Infection control personnel performed plate counts to find the source of the bacteria. Their results:

All of the following conclusions about the bacteria can be drawn except which one?

a. They were present as a biofilm in the pipes.

b. They are gram-negative.

c. They come from fecal contamination.

d. They come from the city water supply.

e. none of the above

Identify where the following processes occur: ammonification, decomposition, denitrification, nitrification, nitrogen fixation. Name at least one organism responsible for each process.

For the following question, answer whether

a. The process takes place under aerobic conditions.

b. The process takes place under anaerobic conditions.

c. The amount of oxygen doesn’t make any difference.

Nitrogen fixation