What makes endocytosis and exocytosis active transport mechanisms?
1) they happen through simple diffusion.
2) they involve taking a large molecule into the cell.
3) they require energy to change the cell membrane.
4) they involve the passage of molecules across the cell membrane.

Ras is a g-protein that is activated when a growth factor attaches to egfr. its activation results in the replacement of a gdp molecule with a gtp molecule, thus allowing a signal transduction pathway to be activated. considering the signal pathway illustrated on this page, what is one potential outcome of a mutation in the ras gene that leads to ras protein hyperactivity. be specific.