14. Lipid 1 Lipid 2

20. 1. The molecular mass of human haemoglobin is 1400 units. When haemoglobin is put into a strong acid, its molecular mass is changed into 350 units. Explain. Haemoglobin is protein which is made up of 4 polypeptide chains. Its quarternary structure is broken by the strong acid and haemoglobin molecules dissociates into 4 polypeptide chains

21. 2. In the process of denaturation of a protein by heating, which structure(s) of the protein is/are mainly damaged ? Why ? Its secondary and quarternary structures, because these structures are mainly maintained by weak hydrogen and ionic bonds which are easily broken by heating.