In the given number line, the fractions represented by points P and Q are $\frac{2}{10} \mathrm{and} \frac{6}{10}$.

In the given number line, the gap between 0 and 1 is divided into 10 equal parts. It can be seen that point P is marked on the 2^nd part to the right of 0, while point Q is marked on the 8^th part to the right of 0.

Thus, the respective fractions represented by points P and Q are $\frac{2}{10} \mathrm{and} \frac{8}{10}$.