Answer to Question #197335 in Biochemistry for Furqan Riaz

Question

The structure of cis and trans oleic acid (C18: 1) is shown in the figure below. They both are 18 carbon fatty acids with one double bond between C9 and CIO.

                                                                   fis           tnnd: O" acid

trans double O" m-id

The melting point of cis oleic acid is 13.4 degrees C and that of trans oleic acid is 44.5 degrees C. Explain this difference in their melting temperatures

Answer 1

Oleic acid has a lower melting point of 13.4 °C. Oleic acid is liquid at room temperature because cis molecules are loosely packed. Elaidic acid has a much higher melting point of 45 °C. Elaidic acid is solid at room temperature because trans molecules are tightly packed