Question

using neurotransmitter signaling. Cells within a biofilm communicate aculation Aerobic bacteria can grow in either high or low oxygen environments, but usually have a slight preference for one or the other. In a parasitic relationship, one member benefits and the other member is neither harmed nor benefited. 7 arawth factors Bacteria and other organisms that use oxygen as part of their metabolic processes often produce toxic by-products called free radicals that can damage bidlogical molecules, like DNA.

Answer 1

4)quorum sensing, Bacterial cells within a biofilm communicate using neurotransmitter signalling

5)Facultative anaerobes can grow with or without oxygen because they can metabolise energy aerobically or anaerobically. They gather mostly at the top because aerobic respiration generates more ATP than either fermentation or anaerobic respiration.

6)Commensalism is a long-term biological interaction (symbiosis) in which members of one species gain benefits while those of the other species neither benefit nor are harmed.

7) The response of bacteria to oxygen is not determined simply by their metabolic needs. Oxygen is a very reactive molecule and forms several toxic by-products, such as superoxide (O2−), hydrogen peroxide (H2O2), and the hydroxyl radical (OH·). Aerobic organisms produce enzymes that detoxify these oxygen products. The most common of detoxifying enzymes are catalase, which breaks down hydrogen peroxide, and superoxide dismutase, which breaks down superoxide. The combined action of these enzymes to remove hydrogen peroxide and superoxide is important because these by-products together with iron form the extremely reactive hydroxyl radical, which is capable of killing the cell. Anaerobic bacteria generally do not produce catalase, and their levels of superoxide dismutase vary in rough proportion with the cell’s sensitivity to oxygen. Many anaerobes are hypersensitive to oxygen, being killed upon short exposure, whereas other anaerobes, including most Clostridium species, are more tolerant to the presence of oxygen.