Question

A scientist wanted to genetically engineer a newtype of corn plant that could withstand cold temperatures. He decided to try to change the composition of the plant's membrane to lower the temperature of phase transition. Which of the following membrane changes might be expected to improve the cold tolerance of the plants?

• A. Increasing the length of the fatty acyl chains
• B. Eliminating all steroids
• C. Increasing the frequency of unsaturated fatty acyl chains
• D. Decreasing the frequency of unsaturated fatty acyl chains

Answer 1

Answer: (C)

Low temperatures can cause a membrane to enter a gel-like phase with very high membrane-lipid viscosity, whereas high temperatures can cause a membrane to become 'hyper fluid with very little viscosity. The temperature dependence of biological membrane is affected by the lipid composition of the membrane. The greater the proportion of unsaturated carbon carbon bonds (double-bonds) in a lipid's fatty acid molecules, the easier solidification of it occurs, in cold temperature and thus the lesser the changes in plants membrane at lower temperature