MCB 2004C Study Guide - Quiz Guide: Electron Acceptor, Anaerobic Respiration, Nitrogen Cycle
Document Summary
Microbial nutrition: bacterial cells are complex & efficient replication machines. Limiting nutrients helps control bacterial overgrowth: essential nutrients are compounds that a microbe must gather from its immediate environment bc it cannot make them itself. However, others such as rickettsias, have complex nutrient requirements and we still cannot grow them using artificial media: microbes are classified by how they gather their essential nutrients, energy, and electrons. Heterotrophs: depend on other organisms to make the organic compounds that they use; co2 is fixed and assembled into organic molecules. Autotrophs: use co2 discarded by heterotrophs to make their complex cell constituents; organic molecules from heterotrophs are acquired outside the cell, broken down for carbon, and the carbon is reassembled as biomass. Chemotrophs: extract energy from oxidation-reduction reactions that remove electrons from high energy compounds and produce lower energy compounds; chemical electron donors are oxidized. Hydrogen (h2), hydrogen sulfide (h2s), ammonium (nh4), nitrate (no2-), and ferrous iron (fe2+)
