A 10 N HCI solution was diluted 10-fold with water and the pH of the diluted solution was measured with a pH meter after calibration using standard solutions. Given that the activity coefficient for diluted HCI was 0.01, the pH of the solution would be (1) 0 (3) 2 (2) 1 (4) 2.5
The pka of acetic acid is 4.76. At what pH would the concentration of acetic acid and acetate ion be the same? (1) pH = 7 (3) pH = 9.8 (2) pH = 6.7 (4) pH = 4.76
Which one of the following amino-containing buffering molecules will be the most able to resist change in pH when in a pH 7.0 solution at a total (ionized and non-ionic) concentration of 100mM? (1) Tris (pKa = 8.1) (3) MOPS {pKa = 7.3} (2) HEPES (pKa = 7.7) (4) PIPES (pKa = 7.1) Concept: Best … Read more
The pH of the blood can be maintained by (1) Myoglobin (2) globulins (3) albumins (4) carbonate/bicarbonate salt
If 5 ml of 20% ethanol is mixed with 25 ml of 80% ethanol, the resulting solution will approximately be (1) 50% ethanol (3) 100% ethanol (2) 70% ethanol (4) 80% ethanol
If you were to take 1.0 ml of a solution of HCl with a pH of 4.0 and add it to 9.0 ml of distilled water, what would be the pH of the final solution? (1) The pH would remain unchanged. (2) The pH would rise to 5.5. (3) The pH would rise to 5.0. … Read more
What will be the required volumes of 1N HCl and 4N NaOH to prepare one litre solution of pH 77 (1) 500 ml, 500 ml. (3) 600 ml, 400 ml (2) 800 ml, 200 ml (4) 200 ml, 800 ml To prepare 1 litre of a solution with pH = 7 using 1N HCl and … Read more
Among the following bonds where rotation is not allowed in a peptide chains? (1) ψ (2) ω (3) x (4) φ In a peptide chain, rotation is restricted due to partial double-bond character of certain bonds. Let’s analyze each option: 1. ψ (Psi) angle – Rotation Allowed ✅ This is the Cα–C bond (between the … Read more
Arrange the three residues, glycine, phenylalanine and proline, in the decreasing order of backbone flexibility (1) Gly > Phe > Pro (2) Pro > Gly > Phe (3) Phe > Pro > Gly (4) It is not possible to comment Backbone flexibility in amino acids depends on the torsional freedom of the main chain (Φ, … Read more
The measured values of main chain torsion angles of a residue in a polypeptide has values (Φ=+50, Ψ=+60). What type of secondary structure is it most likely to be present in?
(1) Left-handed a-helix
(2) Right-handed a-helix
(3) Type II ẞ-turn
(4) Parallel B-sheet