Question

is it true that A cell’s phenotype is determined by its DNA, and its genotype is determined by its proteins. ?????

Answer 1

The proteins do the actual work in a cell, whereas the DNA is the plan or blueprint for the proteins. Since the phenotype of the cell is what it looks like and what it does, it follows that the phenotype is due to the proteins. The genotype is another way of saying what genes it has, which is down to the DNA sequence.