Monomeric molecules in the cell can be joined to form macromolecule polymers. An
ID: 144163 • Letter: M
Question
Monomeric molecules in the cell can be joined to form macromolecule polymers. An example of this is the linking of amino acids to form polypeptide chains.
9) What type of bond is formed between amino acids to form polypeptide chains?
a) hydrogen bond
b) nonpolar covalent bond
c) ionic bond
d) polar covalent bond
10) Which of the following properties make this bond the ideal choice for linking amino acids together to form a polypeptide chain?
a) it is nonpolar
b) it is polar
c) it is electrostatic
d) an enzyme is required to break this bond
e) it is reversible in water
Explanation / Answer
9. It is a non polar covalent bond. Option (b)
Explanation: Amino acid has Amino group (--NH2)at the left and carboxylic group (--COOH) at the right. When two Amino acids are linked together to form polypetide chain they form bond between the C (carboxylic group ) and N (Amino group) by removing the water. Now as bond is forming between C and N there is not much difference in their electronegativity which make them a non polar covalent bond. It is a strong bond, to break this bond high amount of energy will be released.
10. Answer is D. To break any peptide bond an enzyme is required. Because bond is polar covalent in nature which is hard to break by normal process. By using heat or other chemicals it can only make me polypetides denature.
And for the explanation of option E..yes it is reversible in water but it may take so much time like years to break this bond.
So ideal choice of bond for linking Amino acid is that it can only be breakable by enzyme.