Biochemistry Practice Questions Part 2
1. The pH of the blood is maintained by
(a) mineral salts (b) globulins(c) albumins (d) haemoglobin
2. A protein having both structural and enzymatic traits is
(a) actin (b) haemoglobin(c) myosin (d) myoglobin
3. Potassium cyanide stops cell activity by
(a) preventing diffusion of O2(b) blocking trachea
(c) preventing transfer of electrons from cytochrome a3 to O2
(d) coagulating protein carriers
4. Successful Replication of chromosomes does not require the presence of
(a) Ribosomes (b) DNA Template(c) Nuclear enzymes (d) ATP
5. In a diluted starch solution, a-salivary amylase is added at pH 1.6 and kept at 35°C for half an hour and then Iodine solution is added. What would be the result?
(a) no black colour will appear(b) black colour will appear
(c) solution will be clear and colourless
(d) solution will be sweet
6. An amino acid devoid of a free-COOH group can be an
(a) Amine (b) Amide(c) Imine (d) Purine
7. The most striking example of an unique point mutation is found in a disease called
(a) Night blindness (b) Thalassemia(c) Down syndrome (d) Sickle cell anaemia
8. For the formation of one molecule of hexose sugar, how many turns of Calvin cycle are needed ?
(a) Six (b) One(c) Thirty-six (d) One-sixth
9. The hormone that controls pulse rate and blood pressure is
(a) vasopressin (b) oxytocin(c) adrenalin (d) thyroxine
10. The maximum number of Hydrogen bonds in which water molecule can participate is?
(a) 1 (b) 2(c) 3 (d) 4
11. Denaturation of proteins leads to loss of biological activity by
(a) formation of amino acid(b) loss of primary structure
(c) loss of both primary and secondary structure
(d) loss of secondary and tertiary structure
12. The pKa of acetic acid is 4.76. What is the pH of 0.1 M solution of acetic acid?
(a) 5.76 (b) 2.88(c) 2.43 (d) 1.88
13. 40 g of ice at 0 °C and 80 g water at 40 oC are mixed thoroughly, the temperature of the mixture will be
(a) 0° C (b) 10 °C(c) 20 °C (d) 30 °C
14. Galactose and Mannose are two isomeric monosaccharides, which are
(a) Enantiomers (b) Epimers(c) Anomers (d) Diastereoisorners
15. Proteins absorbs maximally UV radiation at 280 nm due to the presence of
(a) Tryptophan (b) Tyrosine(c) Phenyl alanine (d) All of the above
16. Which one of the following solutions will have the least Osmotic Pressure?
(a) 0.5 M glucose (b) 0.5 M NaCl(c) 0.5 M Na2SO4
(d) 0.499 M Starch
17. The free energy change (DG)at the midpoint of helix-coil transition in DNA melting curve is equal to
(a) zero (b) 1.0(c) –1.0 (d) indeterminate
18. DNA is usually dissolved in TRIS-EDTA buffer, EDTA is added to ensure that
(a) DNA is not degraded by nucleases(b) Divalent metal ions are chelated
(c) Both of the above
(d) pH is kept alkaline
19. Two proteins have same molecular weight and same isoelectric point. The best way to resolve them will be by
(a) Ion Exchange Chromatography(b) Gel Filtration Chromatography
(c) Reverse Phase Chromatography
(d) Chromatofocussing
20. Mark the incorrect statement: Ribozyme and Abzyme are
(a) both enzymes(b) both proteins
(c) RNA and protein respectively
(d) able to hydrolyse phosphodiester and peptide bonds respectively
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