The evolutionary effects of the genetic drift are the greatest when the population is small.
In small populations, genetic drift can significantly change the frequencies of the alleles and affect the genetic structure of the population. In big populations, the effects of the genetic drift are small and insignificant.
The functions of lipids include storing energy, signaling, and acting as structural components of cell membranes.
Each cell expresses, or turns on, only a fraction of its genes. The rest of the genes are repressed, or turned off.
The turned on genes are then first transcribed into messenger RNA by the process of Transcription.
Then the mRNA is Translated into protein by the process called Translation.
This is how the specific genes are expressed.