“Biochemical Calculation Questions And Answers You Must Know”

BIOCHEMICAL CALCULATIONS QUESTIONS AND ANSWERS

Many new students often ask questions like: Are there calculations in biochemistry? What is the formula for biochemistry calculation? Should a biochemistry student know mathematics? Etc. Hence, the following are some biochemistry math questions and answers. These problems and direct answers will assist students to quickly revise for examination:

1. What is the pH of a solution with a hydrogen ion concentration of 1 x 10^-4 M? Answer: pH 4.
2. How many moles of glucose (C6H12O6) are present in 500 mL of a 0.1 M glucose solution? Answer: 0.05 moles.
3. If the molar extinction coefficient of a substance is 10,000 M^-1cm^-1 and the absorbance is 0.4, what is the concentration of the substance in the solution? Answer: 0.04 M.
4. Calculate the molecular weight of a peptide with the amino acid sequence Gly-Ala-Lys-Asp. Answer: 435.4 g/mol.
5. How many ATP molecules can be generated from the complete oxidation of one molecule of glucose? Answer: 36-38 ATP.
6. What is the molar concentration of a 2% (w/v) solution of sodium chloride (NaCl)? Answer: Approximately 0.34 M.
7. Calculate the isoelectric point (pI) of a protein with pKa values of 3.5 and 9.0. Answer: pI 6.25.
8. What is the molecular weight of DNA fragment with 500 base pairs? Answer: Approximately 165,000 g/mol.
9. Calculate the volume of a 0.25 M solution of NaOH required to neutralize 25 mL of 0.1 M HCl. Answer: 10 mL.
10. How many molecules are in 2 moles of glucose (C6H12O6)? Answer: 1.21 x 10^24 molecules.
11. If a reaction has a rate constant of 0.02 s^-1 and the initial concentration is 0.1 M, what will be the concentration after 10 seconds? Answer: 0.006 M.
12. What is the pKa of an acid when the ratio of its conjugate base to acid is 10:1? Answer: pKa 1.
13. Calculate the osmolarity of a 0.9% (w/v) sodium chloride (NaCl) solution. Answer: Approximately 308 mOsm.
14. If a sample has an absorbance of 0.6 and a path length of 1 cm, what is the concentration of the substance with an extinction coefficient of 2000 M^-1cm^-1? Answer: 0.3 M.
15. How many grams of ethanol (C2H5OH) are needed to make a 0.5 M solution with a volume of 250 mL? Answer: 23.5 grams.
16. Calculate the specific activity of an enzyme that catalyzes the conversion of 1 μmol of substrate per minute, using a 0.1 mg enzyme preparation. Answer: 10,000 units/mg.
17. What is the percent composition of carbon (C) in glucose (C6H12O6)? Answer: Approximately 40%.
18. If the absorbance of a solution is 0.8 and the path length is 2 cm, what is the molar absorptivity (ε) of the substance? Answer: 0.4 M^-1cm^-1.
19. How many amino acids are present in a protein with a molecular weight of 100,000 g/mol? Answer: Approximately 909 amino acids.
20. Calculate the turnover number of an enzyme that converts 10 μmol of substrate per minute using 1 μg of enzyme. Answer: 10,000 min^-1.
21. What is the molar concentration of a solution containing 0.5 moles of solute in 2 liters of solvent? Answer: 0.25 M.
22. If a reaction has a rate constant of 0.05 M^-1s^-1 and the initial concentration is 0.2 M, what will be the concentration after 30 seconds? Answer: 0.005 M.
23. Calculate the number of water molecules in 1 mole of water (H2O). Answer: 6.022 x 10^23 molecules.
24. How many milligrams of a compound with a molecular weight of 250 g/mol are needed to make a 0.1 M solution with a volume of 100 mL? Answer: 2.5 grams.
25. What is the percent composition of nitrogen (N) in ammonia (NH3)? Answer: Approximately 82%.
26. Calculate the molecular weight of a nucleotide with the sequence ACGT. Answer: Approximately 333 g/mol.
27. How many grams of NaCl are needed to make 500 mL of a 0.5 M solution? Answer: 29.2 grams.
28. Calculate the molarity of a solution containing 2 moles of solute in 500 mL of solvent. Answer: 4 M.
29. What is the dilution factor if 5 mL of a solution is diluted to a final volume of 100 mL? Answer: 1/20 or 0.05.
30. How many kilocalories are produced from the complete oxidation of one mole of glucose? Answer: Approximately 686 kcal.
31. Calculate the volume of a 2 M HCl solution required to neutralize 10 mL of 1 M NaOH. Answer: 20 mL.
32. What is the molecular weight of a nucleic acid with a sequence of 200 bases? Answer: Approximately 66,000 g/mol.
33. How many grams of sucrose (C12H22O11) are present in 250 mL of a 0.5 M sucrose solution? Answer: 149 grams.
34. Calculate the pKa of an acid when the ratio of its conjugate base to acid is 1:10. Answer: pKa 1.
35. What is the molecular weight of a tripeptide with the amino acid sequence Val-Leu-Gly? Answer: 315.4 g/mol.
36. How many ATP molecules can be generated from the complete oxidation of one mole of fatty acid with 18 carbon atoms? Answer: Approximately 146 ATP.
37. Calculate the molarity of a solution containing 0.5 moles of solute in 250 mL of solvent. Answer: 2 M.
38. What is the concentration of a solution if 25 mL of a 0.2 M solution is diluted to a final volume of 500 mL? Answer: 0.01 M.
39. How many molecules are in 5 grams of glucose (C6H12O6)? Answer: 1.68 x 10^22 molecules.
40. Calculate the absorbance of a solution with a concentration of 0.1 M and an extinction coefficient of 1000 M^-1cm^-1 using a path length of 0.5 cm. Answer: 0.05.
41. What is the percent composition of oxygen (O) in ethanol (C2H5OH)? Answer: Approximately 53%.
42. Calculate the molar absorptivity (ε) of a substance if its absorbance is 0.5 and the path length is 1 cm with a concentration of 0.2 M. Answer: 2

.5 M^-1cm^-1.

43. How many amino acids are present in a protein with a molecular weight of 50,000 g/mol? Answer: Approximately 454 amino acids.
44. What is the turnover number of an enzyme that converts 1 μmol of substrate per minute using 0.1 mg of enzyme? Answer: 10,000 min^-1.
45. Calculate the number of carbon atoms in 2 moles of glucose (C6H12O6). Answer: 72 moles.
46. How many milliliters of a 0.1 M NaOH solution are needed to neutralize 50 mL of 0.2 M HCl? Answer: 25 mL.
47. What is the molarity of a solution containing 0.25 moles of solute in 500 mL of solvent? Answer: 0.5 M.
48. Calculate the dilution factor if 2 mL of a solution is diluted to a final volume of 100 mL. Answer: 1/50 or 0.02.
49. How many kilojoules are produced from the complete oxidation of one mole of glucose? Answer: Approximately 2,840 kJ.
50. Calculate the volume of a 3 M NaOH solution required to neutralize 100 mL of 0.5 M HCl. Answer: 16.67 mL.

Please note that some of these calculations have been rounded to a specific number of significant figures. Methods of these calculations amongst others will be shown in subsequent posts.

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