Hi I was just wondering how these are solved (biochem questions)?

Question

A 7mM substrate is diluted 1 in 3. 2.95mL of the diluted substrate is assayed in a cuvette with .05mL of enzyme. What is the concentration of substrate in the cuvette (in micromol/mL)

and

A 6mM substrate is diluted 1 in 5. 2.95mL of the diluted substrate is assayed in a cuvette with .05mL of enzyme. What is the concentration of substrate in the cuvette (in mmol/L)?

thanks

Answer 1

7mM substrate / (1 + 3) = 7/4 = 1.75 mM substrate.

This means 1.75 millimoles per liter (1000 mL) in the diluted solution.

(1.75 mmol / 1000 mL) * 2.95 mL = 1.75 umol * 2.95 = 5.1625 umol

But this was further diluted to 3.00 mL

5.1625 umol / 3.00 mL = 1.721 umol/mL

The other problem is solved the same way.