Question

Chapter 7 Bacterial and Archaeal Growth

6. What are some of the environmental challenges faced by microorganisms and how do they cope with these challenges?

Answer 1

Challenge	Adaptation
High temperature	under high temperature condition, the permeability and fluidity of the membrane increases which disturb the balance of molecules across both the surfaces of the membrane. Therefore the bacterial begins to synthesise saturated fatty acid. Saturated fatty acids are straight chain fatty acids which pack tightly with each other and decrease the permeability of the membrane.
Low temperature	under low temperature condition, the permeability and fluidity of the membrane decreases. So the bacterial cell synthesizes and saturated fatty acid. These are fatty acids with double bond and therefore have a kink in them. Because of this day have a beaded appearance. Therefore they cannot back easily with each other and hence help to increase the permeability of the membrane.
High salt concentration	bacteria living in high salt concentration have salt glands in them due to which they accumulate salt inside them against the concentration gradient.
High pH	bacteria living in alkaline conditions have Transporters located on their membrane which help to pump hydroxyl ions outside the cell against the concentration gradient to maintain a neutral pH
Low pH	bacteria living in acidic conditions have Transporter located on their membrane which help to pump hydrogen ions outside the cell against the concentration gradient to maintain a neutral pH

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