This set of Bioseparation Technology Multiple Choice Questions & Answers (MCQs) focuses on “Biological Material Properties – Electrostatic Charge, Solubility and Partition Coefficient”.
1. Chemical compounds have electrostatic charge due to the presence of ___________
a) R group
b) an ionized group
c) Covalent bond
d) Ionic bond
View Answer
Explanation: The electrostatic charges are developed in a chemical compound because of the presence of ionized group like –NH3+ and –COO–. R group is the part of amino acids, altering the position of R group alters the structure of amino acids. Covalent bond is the sharing of electrons between two non-metallic atoms. Ionic bond is the sharing of electrons between a metal and a non-metal.
2. Some ions carry electrostatic charges depending on the __________
a) Valency
b) Bond
c) Sedimentation coefficient
d) Solubility
View Answer
Explanation: The electrostatic charges depend on the valency of atoms. Valency is the capacity of an atom to lose or gain the valence electron and the number of hydrogen atom available to combine or remove atom. Example, Na+ has valency 1 and the electrostatic charge on it is one positive charge.
3. Isoelectric point is the pH value at which the net positive and negative charge in a protein is same.
a) False
b) True
View Answer
Explanation: The Isoelectric point or pI is the point at which all the net charges are zero i.e. neutral charge is available on the protein. The separation of protein depends on the basis of the charges available on the protein. When the pH > pI then the protein has negative charge while pH < pI tends to have positive charge and when pH = pI, the net charges are neutral and is called Isoelectric point.
4. The nucleic acid has negative charge at physiological pH value due to the presence of large number of __________
a) Carboxyl group
b) Amine group
c) Phosphate group
d) Acyl group
View Answer
Explanation: The nucleic acids are negatively charged due to the presence large number of phosphate groups. Carboxyl group and amine groups are present in the amino acids and protein which gives net charges to the amino acids. Acyl group is the functional group which contains a double bonded oxygen atom and an alkyl group; it is derived from the carboxylic acid.
5. Which separation techniques are based on the electrostatic charges on the molecule?
a) Electrophoresis, ion exchange chromatography, adsorption
b) Filtration, sedimentation, centrifugation
c) Filtration, adsorption, chromatography
d) Chromatography, sedimentation, centrifugation
View Answer
Explanation: Electrophoresis, ion exchange chromatography, adsorption, electrodialysis and precipitation are based on the electrostatic charges on the molecule. Filtration and sedimentation is based on size of the molecule. Centrifugation is based on the size, molecular weight of the molecule.
6. What is the isoelectric point of insulin?
a) 4.9
b) 7.0
c) 11.0
d) 5.3
View Answer
Explanation: The Isoelectric point of insulin is 5.3. The Isoelectric point of albumin protein is 4.9. The Isoelectric point of myoglobin protein is 7.0. The Isoelectric point of lysozyme is 11.0.
7. The polar compounds are more soluble in organic solvent while non-polar compounds are soluble in water.
a) True
b) False
View Answer
Explanation: The polar compounds are more soluble in water and the non-polar compounds are more soluble in organic solvent. Polar compounds cannot be dissolved in organic solvents; it needs external force to be dissolved, so the non polar compounds cannot properly dissolve in water.
8. Solubility of the substance can be influenced by __________
a) temperature, pH, presence of additives
b) pressure, charges, temperature
c) pressure, additives, temperature
d) charges, additives, temperature
View Answer
Explanation: The solubility of the molecule depends on the temperature, pH and the presence of additives in the solution. At the neutral pH the solubility of proteins is very less; therefore the solubility of molecule increases if the pH decreases or increases than the Isoelectric point. Solubility of the molecule increases with the increase in temperature. If some additives are present in the solution which may react with the molecule resulting in formation of precipitate then the molecule will not be able to dissolve in the solution.
9. Which bioseparation process is based on the solubility of the molecule?
a) Electrophoresis, precipitation, crystallization, membrane separation
b) Filtration, precipitation, crystallization, membrane separation
c) Extraction, precipitation, crystallization, membrane separation
d) Chromatography, precipitation, crystallization, membrane separation
View Answer
Explanation: The process of extraction, precipitation, crystallization and membrane separation is based on the solubility of the molecule. Electrophoresis is based on electrostatic charges. Filtration is based on size of the particle to be separated. Chromatography is based on polarity, volatility and the molecular weight of the molecule.
10. The solubility of proteins are influenced by presence of __________
a) Salts
b) Acid
c) Organic compounds
d) Polar group
View Answer
Explanation: Presence of salts in the solution will affect the solubility of the protein. The solubility of the protein increases with the increase in the concentration of salt in the solution. It is called salting in effect. If the ionic strength is less the protein solubility is more. At higher ionic strength, the solubility of the protein will decrease with the increase in the salt concentration in the solution; it is called salting out effect.
11. The measure of distribution of compound between two liquid phases is called __________
a) Sedimentation coefficient
b) Diffusion coefficient
c) Equilibrium constant
d) Partition coefficient
View Answer
Explanation: The partition coefficient is the measurement of distribution of compounds in the liquid phases. It describes about the thermodynamic situation of equilibrium between the phases. It is also called distribution coefficient of the compound.
12. The bioseparation techniques based on partition coefficient are __________
a) Liquid-liquid extraction, partition chromatography
b) Membrane separation, partition chromatography
c) Electrophoresis, partition chromatography
d) Adsorption, partition chromatography
View Answer
Explanation: Liquid-liquid extraction is the separation of compounds or complex metals in immiscible liquids like water and organic solvent based on the relative solubility of the compound and the partition coefficient. Partition chromatography is the separation method for the solutes which uses partition of solutes in the liquid medium.
13. How can you calculate the partition coefficient of the compounds, if a solution of 1g of X in 1000 cm3 of water was mixed with 100 cm3 of acetone, 0.5g of X was transferred to the acetone?
a) 6
b) 7
c) 5
d) 8
View Answer
Explanation: Kpc = \(\frac{concentration\, of\, X\, in\, acetone}{Conentration\, of\, X\, in\, water}\), Concentration of X in acetone = \(\frac{0.5}{100}\) g/cm3 = 0.005 g/cm3, if 0.5 g was transferred to acetone, 1.5 – .5 g = 1g was left in the water. Then the concentration of X in water = \(\frac{1}{1000}\) g/cm3 = 0.001 g/cm3. So, Kpc = \(\frac{0.005}{0.001}\) = 5. The calculated partition coefficient for the compound in the liquid is 5.
14. What happens to the chemical potential of the compound when the distribution of compounds is thermodynamically driven?
a) Higher than the equilibrium
b) Reaches equilibrium
c) Lower than the equilibrium
d) Unstable
View Answer
Explanation: The chemical potential of the compounds reaches equilibrium when the compound is driven thermodynamically. The partition coefficient is determined by the concentrations of the compound at equilibrium.
Sanfoundry Global Education & Learning Series – Bioseparation Technology.
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