Water 1. Hydrogen atoms bonded with carbon do not participate in the hydrogen bonding with other compounds because, Because hydrogen element is smaller than carbon Hydrogen is not an electronegative element The difference between electronegativity of both the elements is not much Both elements belong to separate group in the periodic table None 2. Which of the following strategy the plant and bacterial cells have to resist the osmotic pressure Presence of a rigid cell wall Ability to maintain equal concentration in the cell and in the extracellular fluids Presence of vacuole Reducing the cytosolic osmolarity to a significant level None 3. Which of the following is true about the ion product of water? It is also represented as Kw It is calculated as [H+][OH−] It constant at 25◦C All of the above None 4. Why hydrogen bonds are said to be 10% covalent and 90% electrostatic? Because of the intermolecular sharing of the electrons Overlapping in the bonding orbitals O-H bonds are partial covalent bond All of the above None 5. In the most stable ‘native’ structure of the biomolecule weak interactions are maximised. True False None 6. A three dimensional shape of a polypeptide Is a most stable form polypeptide conformation Is facilitated by maximised weak interactions Contributes to overall increase in the entropy All of the above None 7. What is the best thermodynamic explanation about the solubility of the non-polar compounds in the water System gains small enthalpy Entropy decreases ΔG is positive. All of the above None 8. Which of the following is true of the shape of the water molecule? It is a perfect tetrahedron H-O-H bond angle is 109.5° Shape of water molecule is a nearly tetrahedron It is not a tetrahedron None 9. The importance of hydrogen bonds in biology is/are that, They are essential in the formation of the three dimension structures of the protein and other biomolecules High heat capacity of the water due hydrogen bonding confers resistant to sudden temperature changes in the body of the organism Formation of the stable cell membranes in aquatic solutions. All of the above None of the above None 10. Observe the following molecular structure and choose one the following that explains the difference between the boiling point of the molecules. CH3CH2CH2CH2CH3 b.p. -0.5◦ C CH3CH2CH2CH2OH b.p. 117◦ C Second compound can form intermolecular hydrogen bonds OH group containing compounds are solid 3D conformation of the 1st compound leads to increased the boiling point None of the above None Time's up
