Question

The following molecules represent the four biomolecules. Examine the structures and answer the questions: Carbohydrates (Amylose), Nucleic Acids (DNA), Proteins (Peptide), and Lipids.

1. Which biomolecule(s) is/are likely to form ionic interactions with water? Explain your choice(s).

2. A. Which biomolecule(s) is/are likely to form hydrogen bonds with water? Explain your choice(s)     B. Identify the H donors and acceptors in those that can form hydrogen bonds.

3. Which biomolecule(s) is/are likely to experience hydrophobic effects? Explain your choice(s).

4. Which molecules would you expect to have the greatest contribution from van der Waals forces?

5. Which of the molecules would you expect to be soluble in water? Why?

Answer 1

1. Ionic interaction involve bonding between two ions of opposite charge. Ionic interaction of biomolecule include interaction with polar group of water. The biomolecules that could form interaction with water is protein and nucleic acid because they have polar group attached.

2.

A. The proteins and nucleic acid could form hydrogen bond wih water because they have polar group that can bond with water which is having polar group. Amino acid serine, threonine are polar and having OH group.

B. A more electronegative atom will be the hydrogen acceptor and less electronegative atom is hydrogen donor. Here, oxygen atom in the OH group of amino acid serine, threonine and nitrogen atom in lysine, arginine could act as hydrogen acceptor and hydrogen atom of water could act as hydrogen donor.

3. The lipid molecules are more likely to experience hydrophobic effect because lipid molecules are hydrophobic molrcules because of lack of any polar group.

4. Vander wall interaction is a distance dependent interaction between two or more atom. Protein is expect to have greatest contribution from an Vander wall because of the presence of aromatic and aliphatic side chains.

5. Uncharged but polar group containing group dissolve in water.  Therefore nucleic acid, protein and amylose(little bit) is soluble in water.