Question

1. what is the dilution factor if you add 100ul of protease solution to 100 ul of diluent?

a. 1/1
b. 1/2
c. 1/4

1. if you perform a 5 - step 2 - fold dilution, what is the dilution factor at the last step?

a. 2^{-2}
b. 2^{-3}
c. 2^{-4}
d. 2^{-5}

Explanation:

Step1: Calculate dilution factor for question 5

Dilution factor = $\frac{V_{total}}{V_{sample}}$
$V_{total}=100\ \mu L + 100\ \mu L=200\ \mu L$, $V_{sample} = 100\ \mu L$
Dilution factor = $\frac{200}{100}= \frac{1}{2}$

Step2: Calculate dilution factor for question 6

In a 2 - fold dilution, each step has a dilution factor of $\frac{1}{2}=2^{-1}$.
For a 5 - step 2 - fold dilution, the overall dilution factor at the last step is $(2^{-1})^5 = 2^{-5}$

Answer:

1. B. 1/2
2. D. $2^{-5}$