Question

(Bacteria cultured in saturated fatty acids at low temperature vs high temperature)

(2) Saturated fatty acid (6) Cusaturated fatty acid l'almitic acid Linoleic acid 200: Sins Assxiatec Figure 1: Structure of saturated (a) and unsaturated (b) fatty acids (http://www.columbia.edu.cu biology courses/c2005/purves6/figure03-20.jpg) 1. Acholeplasma laidlawii is a bacterium that is unable to synthesize its own fatty acids and must therefore construct its plasma membrane from whatever fatty acids are available in the environment. Thus the A. laidlawii takes on the physical characteristics of the fatty acids available at the time. If A. laidlawii is grown in a medium that contains, to a large extent, saturated fatty acids, how would this bacterium fare in: a. Low temperature environments? Explain (5 points) b. High temperature environments? Explain (5 points)

Answer 1

It is given that there is an abundance of saturated fatty acids in the medium. So the bacteria will incorporate these fatty acid into its plasma membrane. Saturated fatty acids are strait chain molecules which can tightly pack with each other. They help in decreasing the permeability of the membrane because when they tightly pack with each other, molecules find it very difficult to cross the plasma membrane.

A. If the bacteria is living in low temperature condition, then it will face problems if saturated fatty acids are incorporated into membrane. This is because under low temperature, the permeability and fluidity of the membrane decreases because phospholipids tightly packed with each other. And if more amount of saturated fatty acid are incorporated into the membrane, then permeability will decrease more and the bacteria will face problem in taking up the molecules from outside.

2. If the bacteria is living under high temperature condition, then the bacteria will survive easily. This is because under low temperature, the permeability and fluidity of plasma membrane increases. So to balance this permeability and fluidity, more amount of saturated fatty acids are incorporated into the membrane. These straight chain molecules can pavk tightly with each other and help in decreasing the permeability and the bacteria is already living in environment containing saturated fatty acid so in this give the bacteria will be benefited.

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