1. The melting points of a series of 18-carbon fatty acids are stearic acid, 69.60C, oleic acid, 13.40C; linoleic acid -50C; and linolenic acid, -110 What structural aspect of these 18-carbon fatty acids can be correlated with the melting point? Provide a molecular explanation for the trend in melting points.

How do the different structures affect the melting points ofsaturated, monounsaturated and polyunsaturated fatty acids?

37. Which of the following is a common feature of lipids?

(a) All lipids have glycerol in their structures.

(b) All lipids have fatty acids in their structures.

(c) All lipids have hydrophobic regions in their structures.

(d) No lipids have hydrophilic regions in their structures.

(e) More than one of the above is true.

38. Which of the following statements is true?

(a) Fatty acids with a greater degree of saturation have fewer C=C double bonds and form glycerides have higher melting points.

(b) Fatty acids with a greater degree of saturation have more C=C double bonds and form glycerides have higher melting points.

(c) Fatty acids with a greater degree of saturation have fewer C=C double bonds and form glycerides have lower melting points.

(d) Fatty acids with a greater degree of saturation have more C=C double bonds and form glycerides have lower melting points.