What is the function of messenger RNA (mRNA) in protein synthesis?

Messenger RNA (mRNA) plays a crucial role in the process of protein synthesis by carrying genetic information from DNA to the ribosome, where proteins are synthesized. During transcription, the genetic code in DNA is transcribed into mRNA. This mRNA molecule then travels from the nucleus (where DNA is located) to the cytoplasm, where ribosomes are found. The ribosomes read the sequence of nucleotides in the mRNA and translate this information into a specific sequence of amino acids, ultimately forming a protein.

The other options pertain to different functions that are not associated with mRNA. Translating proteins is a function performed by ribosomes and transfer RNA (tRNA), which brings the appropriate amino acids according to the sequence encoded by the mRNA. Splicing DNA is a process involved in the modification of RNA after transcription, where introns are removed, which involves other molecules, not mRNA itself. Synthesizing amino acids is also not a role of mRNA; instead, amino acids are derived from dietary proteins or synthesized in the body from simpler compounds. Thus, the primary and defining role of mRNA is indeed to transport the genetic instructions necessary for protein synthesis from DNA to the ribosome.