9. Saturated fats contain only single bonds, while the unsaturated fats contain at least 1 double bond. Saturated fats are generally not considered healthy, while unsaturated fats are preferred due to antioxidant content, apart from cholesterol control. The former have high melting point, while the latter are characterized by low melting point.
10. Triacylglycerols are synthesized from three fatty acid molecules, joined by one glycerol molecule. Examples of triacylglycerols are olive and corn oil. They are the form in which fat energy is stored in adipose tissues.
11. A peptide bond is represented as CO-NH bond or bond involving amine group of one molecule and carboxyl group of other molecule. It will form between the carboxyl group and amino group of reacting molecules.
12. There are four levels of protein structures: primary (linear arrangement of amino acids and location of covalent linkages), secondary (locations of folding), tertiary (ultimate 3-D structure) and quaternary (non-covalent interactions, such as in hemoglobin).