Carbon metabolism in bacteria is either heterotrophic, where organic carbon compounds are used as carbon sources, or autotrophic, meaning that cellular carbon is obtained by fixing carbon dioxide. Heterotrophic bacteria include parasitic types. Typical autotrophic bacteria are phototrophic cyanobacteria, green sulfur-bacteria and some purple bacteria, but also many chemolithotrophic species, such as nitrifying or sulfur-oxidising bacteria. Energy metabolism of bacteria is either based on phototrophy, the use of light through photosynthesis, or based on chemotrophy, the use of chemical substances for energy, which are mostly oxidised at the expense of oxygen or alternative electron acceptors (aerobic/anaerobic respiration). COUNT 5
QSN1 How does heterotrophic carbon metabolism occur? ANS1 organic carbon compounds are used as carbon sources QSN2 When carbon metabolism is called autotrophic? ANS2 cellular carbon is obtained by fixing carbon dioxide QSN3 What category do parasitic bacteria fall into? ANS3 Heterotrophic bacteria QSN4 Green sulfur-bacteria is typical representative of what type of bacteria? ANS4 autotrophic bacteria QSN5 What is chemotrophy ? ANS5 the use of chemical substances for energy