I believe proteins are synthesized from amino acids during synthesis reactions.
Protein synthesis starts with transcription of mRNA from a DNA gene in the nucleus.Various types of RNA may have been synthesized using the appropriate DNA. The RNAs migrate from the nucleus to the cytoplasm where the process of translation takes place. During the process the mRNA with the codons (three nucleotide bases that code for a specific amino acids) is interpreted by the anticodons in the tRNA , thus forming amino acids with together forms polypeptides and then proteins are formed.
The correct answer is the arterial blood carbon oxide level.
Arterial blood test measures oxygen and carbon dioxide levels in the blood. It also measures the body's acid-base level, which is normally balanced when an individual is healthy. The normal range for carbon dioxide is 23 to 29 mEq/L.