Answer:
Active uptake (which I think you mean active transport) is important when the concentration gradient is against that of a certain substance, so it doesn't cross the membrane through diffusion or passive transport. It is sometimes necessary if a substance needs to move across a membrane but can't do so due to electrical charge or that there is a substance on the other side of the membrane preventing diffusion.
Explanation:
It is the nucleus that contains DNA and controls the functions of the cells
The statement " Each gene in the human genome codes for a single protein. "is just wrong, as according to the basic knowledge of human genome, o<span>nly about 2 percent of the genome codes for proteins. This answer does make difference and clearly explaines why the previous one is wrong. Hope you will find it helpful!</span>
