Metabolic Diveristy Of Microorganisms

Question 1

What is catabolism?

Answer 1

Degradation of chemicals to yield energy (electrons) and waste products

Question 2

What is anabolism?

Answer 2

Synthesis of new compounds using energy

Question 3

What is metabolism?

Answer 3

Deals with the flow of carbon and electrons through living systems

Transfer of electrons usually accompanied by a H+

Question 4

What are the three main processes involved in the break down or glucose?

Answer 4

Glycolysis
TCA cycle
Oxidative phosphorylation

(See cells and biomolecules module for full processes)

Question 5

What are some commonly used terminal electron receptors in anaerobic respiration?

Answer 5

Fe(3+)
Mn(4+)
NO3(-)
NO2(-)
N2O
SO4(2-)
S
CO2
Exogenous organic compounds

Question 6

What happens in sulfate reduction?

Answer 6

Carried out by a specialized group of anaerobic bacteria (sulfate reducing bacteria)

Most SRB belong to Deltaproteobacteria. However the arcgaeal domain also contains sulfate reducers. e.g Desulfovibrio, Desulfococcus, Desulfobacter, Desulfobulbus, Desulfobulbus, Desulfotomaculum, Archaeoglobus

Sulfate is stable so must be activated. Converted to adenosine phosphosulfate which is then reduced

SRB can use the enzyme hydrogenase to split H2 into 2 protons and two electrons. Protons are produced extracellular oh to form a PMF
Electrons fed into ETC and reduce APS (adenosine phosphosulfate)

Question 7

What happens in iron and manganese reduction?

Answer 7

Bacteria capable of this- Geobacter spp and Shewanelle putrefaciens

Geobacter spp have been implicated in organic pollutant removal in contaminated anoxic aquifers. Manganese and iron reduction significant in organic matter turnover in organic rich terrestrial environments. Also mobilization of toxic heavy metals associated with iron oxides. Also release id phosphate from anoxic sediments.

These bacteria use hydrogen shirt chain fatty acids and simple aromatic compounds as electron donors

Iron reducing bacteria have outer membrane cytochromes that facilitate electron transfer to electron acceptors. Some directly pass electrons to solid phase iron oxides, others use soluble electron carriers to transport electrons from the cells to solid phase mineral electron acceptors.