Question

How are a few microbes able to survive in extreme heat and cold?

Answer 1

Microbes are organisms, which are too tiny or minute, to be seen without the usage of a microscope. They are inclusive of bacteria, archaea, fungi, protists and single-celled eukaryotes like paramecium, amoeba. Prions and viruses are regarded as non-living things as they need a host to carry out functions and so, they are not considered as microbes.

Complete answer
Though many microbes are able to live in ambient temperatures, a few of them are able to survive easily in extreme temperatures. Pyrococcus furiosus can be isolated from a shallow submarine hot spring, which is able to survive in extremely high temperatures. It can grow competently even at 100 °C and above. Since it adapted itself metabolically, there is no problem for it to survive at such extremely high temperatures.

Some of them have competent survival mechanisms, which are already incorporated in their genome. They synthesize a plethora of enzymes and proteins, which aid them overcome the difficulty. They usually produce “cold shock” and “heat shock” proteins, which save the bacterial cell from extreme cold and heat environments respectively.

Cold shock proteins aid the bacteria to survive in temperatures lesser than the optimum temperature and the heat shock proteins make bacteria survive in temperatures greater than the optimum growth temperature. This is achieved due to organization of prokaryotic nuclei and condensation of chromosomes.

Microbes are capable of synthesizing particular enzymes, which make them function at extreme temperatures. The enzymes and proteins’ molecular structure need to be flexible and less stable, so that they are able to assume different conformations depending on the need of the environment, which will indirectly aid the microbes to survive in extremity.

Note:
Enzymes and proteins adapted to higher pressures are more flexible than at normal pressure. Low temperature microbe genes are helping in improvement of drought and cold tolerance in plants. High temperature microbes can be utilized for the generation of hydrogen gas through carbon monoxide and gas as substrates. This serves as a biofuel, which is very valuable in the near future.