12. which statement best describes the relationship between cells, DNA, and proteins?
ODNA is composed of proteins that carry coded information for how cells function.
Cells contain DNA that controls the production of proteins.
Cells are linked together by proteins to make different kinds of DNA molecules.
Proteins are used to produce cells that link amino acids together into DNA.

Explanation: Cellular DNA controls protein synthesis. DNA is first transcribed into an RNA in a process called transcription. There are three classes of RNA: messenger RNA (mRNA), transfer RNA (tRNA) and ribosomal RNA (rRNA). Transcription is the process of copying the genetic information encoded in a DNA molecule into an RNA. Transcription occurs in the nucleus of the cell. The RNA produced is transported to other parts of the cell where it is needed. mRNA is transported to the ribosome where protein synthesis takes place. At the ribosome, the mRNA molecule is used to produce protein in a process known as translation. Therefore, DNA controls the production of proteins. The genetic information contained in the DNA determines the type and function of the protein produced.