Question

Why is RNA necessary to act as a messenger? Why can't the code be taken directly from the DNA? How do some cells become brain cells and others become skin cells, when the DNA in ALL the cells is exactly the same? In other words, if the instructions are exactly the same, how does one cell become a brain cell and another a skin cell?

Answer 1

Answer:

In other words, if the instructions are exactly the same, how does one cell become a brain cell and another a skin cell? it has the ability to turn off genes. ... a cell grows, prepares for division, and divides into two new cells which are called daughter cells.