1. Which among the following interactions is the weakest?
a) Ionic bond
b) Hydrogen bond
c) Hydrophobic interactions
d) Vander Waals interactions
Explanation: The bond energy of various bonds is as follows: hydrogen bonds (8-21 kJ/mol), ionic bonds (42 kJ/mol), Hydrophobic interactions (4-8 kJ/mol), Vander Waals interactions (4kJ/mol). Hence, among the given options Vander Waals interactions are the weakest interaction.
2. Vander Waals force arises from the attraction between transient dipoles generated by the rapid movement of electrons around the neutral atom
a) False
b) true
Explanation: Vander Waals interactions are a type of non-covalent interactions. They are the weakest of the non-covalent interactions. Vander Waals force arises from the attraction between transient dipoles generated by the rapid movement of electrons around the neutral atom. Hence, the above statement is true.
3. Which of the following interactions involves charged groups?
a) Hydrophobic interactions
b) Disulfide bond
c) Hydrogen bond
d) Ionic bond
Explanation: Ionic bonds are a type of non-covalent interactions. Ionic interaction is due to the electrostatic interaction of two charged molecules. Hydrophobic interactions, disulfide bonds, and hydrogen bonds do not involve charged molecules. Hence, the ionic bond is the correct option.
4. The weak attractive forces of non-covalent interactions are not at all important for determining the properties and functions of biomolecules.
a) true
b) false
Explanation: Hydrogen bonds, hydrophobic interactions, Vander Waals interactions, and ionic bonds are all non-covalent interactions. The weak attractive forces of non-covalent interactions are important for determining the properties and functions of biomolecules. Hence, the above statement is true.
5. Which of the following has bonds in increasing order of their strength?
a) Ionic bond > Covalent bond > Hydrogen bond > Hydrophobic interactions > Vander Waals interactions
b) Covalent bond > Ionic bond > Hydrogen bond > Hydrophobic interactions > Vander Waals interactions
c) Covalent bond > Hydrogen bond > Ionic bond > Hydrophobic interactions > Vander Waals interactions
d) Covalent bond > Ionic bond > Hydrogen bond > Hydrophobic interactions > Vander Waals interactions
Explanation: There are mainly two types of interactions viz. covalent and non-covalent interactions. Covalent interactions are stronger than non-covalent interactions. In non-covalent interactions the order of strength is Ionic bond > Covalent bond > Hydrogen bond > Hydrophobic interactions > Vander Waals interactions.
6. Which of the following interactions determine the water solubility of uncharged molecules?
a) Covalent bond
b) Hydrophobic interactions
c) Vander Waals interactions
d) Hydrogen bond
Explanation: Hydrogen bond is a type of non-covalent interaction. It is the attraction between a polar hydrogen atom and an electronegative atom. Charged molecules are readily soluble in water due to ionic interactions. But uncharged molecules can be soluble in water if they form hydrogen bonds with water. Thus, hydrogen bonds determine the solubility of uncharged molecules in water.
7. Molecular complementarity leads to a lock-and-key fit between biomolecules. It is due to which type of interactions?
a) Covalent bond
b) Hydrophobic interactions only
c) Ionic bonds only
d) Non-covalent interactions
Explanation: The majority of biomolecules interact through non-covalent interactions. Although individually these interactions are weak, multiple non-covalent interactions at close range between biomolecules create a considerably strong interaction.
8. Which among the following has the strongest interaction?
a) Vander Waals interactions
b) Ionic bonds
c) Hydrogen bond
d) Covalent bond
Explanation: The strength of a bond can be determined by its bond energy. The bond energies of the given interactions are Vander Waals interactions (4kJ/mol), ionic bonds (42 kJ/mol), hydrogen bonds (8-21 kJ/mol), covalent bonds (∼400 kJ/mol). Hence, among the given options covalent bond has the strongest interaction.
9. Which among the following has the strongest interaction?
a) Vander Waals interactions
b) Hydrophobic interactions
c) Hydrogen bond
d) Ionic bonds
Explanation: The bond energy of interaction is a representation of the strength of the interaction. The bond energies of the given interactions are Vander Waals interactions (4kJ/mol), ionic bonds (42 kJ/mol), hydrogen bonds (8-21 kJ/mol), hydrophobic interactions (4-8 kJ/mol). Hence, among the given options ionic bond has the strongest interaction.
10. If the energy required to break all non-covalent interactions between two molecules is 750 kJ/mol, then what is the total number of hydrogen bonds present between them? (Assume there are only hydrogen bonds between them and the bond energy of each hydrogen bond is 15 kJ/mol)
a) 11,250
b) 25
c) 100
d) 50
Explanation: The correct answer is 50.
Formula: No. of bonds(n)=\(\frac{Total \, Energy \, Required \, To \, Break \, All\, Bonds }{Energy \, of \, Single \, Bond}\)
n=\(\frac{750}{15}\)
n=50.