Wayne thinks that DNA is only present in cells that need the information to make proteins. Sandy disagrees, and thinks that all cells have the same DNA, and they only make proteins from the genes that they need. Who is correct? Give specific evidence.

The correct answer is: Sandy is correct, all cells contain all the DNA.

Explanation:

Sandy is the one who is making the correct statement here because all cells (minus some exceptions) contain ALL the DNA. Different cells have different requirements so each cell will translate into proteins the part of the DNA that has the specific gene for the protein the cell needs to synthesize.

For example, excitatory cells like neurons or cardiac cells need gated ion channels that are made of specific proteins to allow the passing of molecules like sodium and potassium. For this reason, these cells will use a particular gene in the DNA, adapt it into an mRNA strand through a process called Transcription, and then use different structures such as ribosomes and tRNA to help synthesize the protein needed from that mRNA strand (this process is called Translation).

All of the parts of the DNA that are not used by a cell will remain silent, while the genes that are used are expressed in the cell. This disparity between different parts of the DNA is thanks to the process of gene regulation, which "turns genes on and off".