What is the molar concentration of water in a solution of 10mM glucose?

Question

1) How does the pH of a solution affect its solubility and structure of weak organic acids and bases, such as proteins and nucleic acids?

 

2) What is the molar concentration of water in a solution of 10mM glucose? 

Answer 1

Question 1:

1. Proteins and nucleic acids contain ionizable groups (like –COOH, –NH₂, phosphate).
2. The pH of the solution affects whether these groups are protonated or deprotonated.
3. At certain pH values, molecules may become more charged → increasing solubility in water (since charged molecules interact better with water).
4. At other pH values, groups may lose their charge → reduced solubility and possible aggregation.
5. Structure is also affected: proteins may unfold (denature) if pH is too acidic or too basic, because ionic bonds and hydrogen bonds are disrupted. Similarly, nucleic acids can lose stability if the pH is far from neutral.

Answer: pH changes the ionization of acids and bases in biomolecules, which alters their solubility and can disrupt their 3D structure.

Question 2:

We want the concentration of water in the solution.

1. Pure water concentration:
2. Density of water = ~1000 g/L
3. Molar mass of water = 18 g/mol

1000/18 = 55.5 M

1. Effect of 10 mM glucose:
2. 10 mM = 0.01 M glucose.
3. Compared to 55.5 M water, this is tiny.
4. So the water concentration is:

55.5 - 0.01 = 55.49 M

Answer: The molar concentration of water in 10 mM glucose is ≈ 55.5 M (essentially unchanged).