Answer to Question 1
Atoms or other groups may exist as cis or trans forms around the double bond of the fatty acids. Cis and trans forms have the same number of carbon, hydrogen, and oxygen atoms but in a different geometrical arrangement. A longer carbon chain increases the melting point; the more double bonds, the lower the melting point; and cis fatty acids have a lower melting point than do trans.
Answer to Question 2
Monoglycerides and diglycerides are used as emulsifiers in a variety of foods.