Lecture 16 - Anaerobic Respiration

Question 1

anaerobic respiration

Answer 1

involves a terminal electron acceptor that is not oxygen

Question 2

In general, _____ energy id generated compared to aerobic respiration because, the reduction potentials of the electron acceptors are less positive when compared to oxygen.

Answer 2

less

Question 3

anaerobic respiration is an example of _____ reduction/metabolism.

Answer 3

dissimulative metabolism

Question 4

reduction of chemicals for energy, the products are typically excreted

e.g. when nitrate is reduced in denitrification, N2 gas is formed and excreted

Answer 4

dissimulative metabolism

Question 5

assimulative metabolism

Answer 5

chemical is converted into cell biomass (cellular biosynthesis)

Examples:

• use of nitrate (NO3 -) for conversion of amino acids
• reduction of CO2 into cell matter

Question 6

anaerobic respiration in which NO3 - is reduced to gaseous nitrogen compounds, primarily N2

Answer 6

denitrification

Question 7

What chemicals are involved in denitrification ?

Answer 7

nitrite (NO3 -) –> NO2-
nitrite oxide (NO) –> nitrous oxide (N2O)
–> nitrous gas (N2)

Question 8

Why is denitrification relevant to wastewater treatment?

Answer 8

• reduces the amount of nitrate released to surface waters

- reduces risks of eutrophication

Question 9

Why is denitrification relevant to agriculture?

Answer 9

• when nitrate is applied as fertilizer
• denitrification redues nitrate to gaseous nitrogen compounds; these can no longer be used by plant
• ag is a major contributor to N2O emission s