1 Briefly explain why we has to shake the salad dressing a m

1. Briefly explain why we has to shake the salad dressing, a mixture of olive oil and vinegar, before pouring it onto her salad.

2. Wax, also a lipid, is an ester of a long chain alcohol and a long chain carboxylic acid. Write the structure of beeswax that contains 16 carbon of carboxylic acid and 30 carbon of alcohol.

3. Your doctor says your good cholesterol and bad cholesterol are in proper ratio. Briefly compare the structures and functions of the good and bad cholesterols.

4. Explain how bile salt acts as an emulsifier to aid the digestion of dietary fats.

5. Linoleic acid is abundant in many vegetable oils, such as corn, safflower, soybean, and sunflower oils; it is one of the essential fatty acids for humans. Classify linoleic acid as saturated, monounsaturated, or polyunsaturated. Is it a cis- or trans-fatty acid? Is it an omega-3, 6, or 9?

Solution

1) Olive oil (or any other oil) is very different from vinegar. Even after a lot of shaking, they eventually separate into different layers and that is why the mixture should be mixed thoroughly before adding to the salad.

Vinegar is made up of acetic acid and wate rmainly. These molecules are polar in nature (with an electronegative end and one electropositive end). These polar molecules get attratced to water (as water too is polar). Their opposite charged ends attract and such molecules are called hydropilic.

Whereas oil is a type of fat (containing long molecules of fatty acids) and is non-polar in nature. It is hydrophobic in nature as it doed not get attracted towards water layer or other polar molecules.

This is the reason olive oil and vinegar do not mix and separate which is why they should be shaken together thoroughly to get a good emulsion and then be added to the salad.