Bacterial Life Processes”Biological Classification” Botany Notes Chapter 2, for Class 12-CBSE

Bacterial Life Processes

Discussion of bacterial life processes revolves around the study of the prominent metabolic activates like  respiration and nutrition.

(A) Respiration : on the basis of mode of respiration, the bacteria are divided into two main groups ; i.e., aerobes and anaerobes. Each group is further of two types i.e. strict or obligate and facultative.

1. a) Obligate or strict aerobes : These bacteria can live only in presence of oxygen as they possess the enzyme system for aerobic respiration only. In the absence of oxygen, they cannot respire and thus, die, e.g., Bacillus subtilis.
2. b) Facultative anaerobes : They normally respire aerobically. However. They are capable of switching over to anaerobic mode to get energy for their survival, if sufficient oxygen to sustain aerobic respiration is not available in the environment, e.g., Pseudomonas.
3. c) Obligate or strict anaerobes : These bacteria respire an aerobically only. The growth of such bacteria will certainly be shower as anaerobic respiration liberates much less amount of energy as compared to aerobic respiration. They lack enzymes necessary for carrying out aerobic respiration e.g., Clostridium botulinum.
4. d) Facultative aerobes : They normally respire an aerobically, but are capable of respiring aerobically as well, if oxygen is available. Most of the photosynthetic bacteria are facultative aerobes e.g., photosynthetic bacteria Chlorobium.