A Question with both poisson and gamma distribution

A Question with both poisson and gamma distribution

Suppose X denote the number of bacteria per cubic centimeter in a
particular liquid and that X has a Poisson distribution with parameter
$\lambda$, further, suppose that $\lambda$ varies from location to
location and has a Gamma distribution(2,5) If we randomly select a
location
a)What is the expected number of bateria $cm^3$?
b) what is the standard deviation of the number of bacteria $cm^3$
I am confused by the combination of two distribution. If $\lambda$ is of
Gamma(2,5) then is it equal to $25e^{-10}X$ ? so $E(x)$ is the same? any
help is really appreciated!