Why does cells have same DNA but different proteins?

Question

Why does cells have same DNA but different proteins?

Answer 1

Also many cells have very different DNA. Consider the sperm and egg cells which have only half of the usual amount of DNA in them.

There are also cells in the immune system that undergo loss of DNA in the process of maturation. This is a very interesting process because it basically constitutes a deprogramming of the cell's nucleus for certain types of information.

Answer 2

Different sets of genes are expressed in different times, and in tissues.

Answer 3

chromosomes are made of a protein, and a substance called DNA. it is the DNA which carries the instructions for the the protein that cell is to make.

different proteins means that each protein has its own function in cell.

the amino acids are not joined together haphazardly. the order in which they are joined, and so the kind pf protein they make, is very carefully organized. the instructions for this are kept in the DNA. in the nucleus.

Answer 4

Different genes are expressed in different cells.

Answer 5

Not all of a cell's genes are expressed at the same time -- just a subset.  Gene expression is tightly regulated in every cell -- they have to be turned on.  That's what gives each cell type its different identity -- why a liver cell is different from a neuron, because they are *expressing* different genes, even though those same genes are present in both cells, just some are silent (they stay packaged up in condensed chromatin).

Answer 6

Not all cells have the same exact DNA. Mutations occur, allowing for a difference in each cell's genome. However, these are small, and have a potential to have a great effect.

However, a better explanation is that even though the same DNA is used, different introns and exons can be used. Think of a jumble of letters. You dont need to use all of them to form words. The same goes for DNA as well. Different parts of the DNA can be used to created different proteins.