Metabolism using an electron transport system is classified

Metabolism using an electron transport system is classified based on the nature of the initial electron donors and terminal electron acceptors. Lithotrophy s defined as the use of A. organic molecules as the initial electron donors. B. organic molecules as the final electron acceptors. C. inorganic molecules as the initial electron donors. D. inorganic molecules as the final electron acceptors. E. Two of the above are correct. Which of the following forms of energy production does NOT involve the formation of a proton gradient to synthesize ATP? a. Fermentation b. Oxidative respiration c. Phototrophy d. All forms at energy production require a proton motive force. Which is false among A-C regarding glycolysis? A. It initially requires energy input in the form of ATP hydrolysis B. It yields ATP and NADH C. It forms ATP via substrate level phosphorylation D. none of A-C are false; all are true

Solution

Answer:

1). C. Inorganic molecules as the initial electron donrs

Lithotrophy is the use of an inorganic compound as a source of energy. Most lithotrophic bacteria are aerobic respirers that produce energy in the same manner as all aerobic respiring organisms: they remove electrons from a substrate and put them through an electron transport system that will produce ATP by electron transport phosphorylation. Lithotrophs just happen to get those electrons from an inorganic, rather than an organic compound.

Lithotrophic sulfur oxidizers include both Bacteria (e.g. Thiobacillus) and Archaea (e.g. Sulfolobus). Sulfur oxidizers oxidize H₂S (sulfide) or S (elemental sulfur) as a source of energy. Similarly, the purple and green sulfur bacteria oxidize H₂S or S as an electron donor for photosynthesis, and use the electrons for CO₂ fixation

2). D. All forms of energy production require a proton motive force

3). D. none of A-C are false; all are true