RNA and Protein Synthesis

Ribonucleic Acid (RNA)

a nucleic acid present in all living cells which acts as a messenger carrying instructions from DNA for controlling the synthesis of protein


one of the four nucleobases in the nucleic acid of RNA that are represented by the letters A, G, C and U

Messenger RNA (mRNA)

the form of RNA in which genetic information transcribed from DNA as a sequence of bases is transferred to a ribosome

Transfer RNA (tRNA)

RNA consisting of folded molecules that transport amino acids from the cytoplasm of a cell to a ribosome.

Ribosomal RNA (rRNA)

a molecular component of a ribosome, the cell's essential protein factory (it makes polypeptides)


the process by which the information in a strand of DNA is copied into a new molecule of messenger RNA (mRNA). DNA safely and stably stores genetic material in the nuclei of cells as a reference, or template


A sphere-shaped structure within the cytoplasm of a cell that is composed of RNA and protein and is the site of protein synthesis. Ribosomes are free in the cytoplasm and often attached to the membrane of the endoplasmic reticulum. Ribosomes exist in both

Protein Synthesis

The creation of proteins by cells that uses DNA, RNA and various enzymes.

Amino acids

a simple organic compound containing both a carboxyl (�COOH) and an amino (�NH2) group


A set of three adjacent nucleotides, also called triplet, in mRNA that base-pair with the corresponding aniticodon of tRNA molecule that carries a particular amino acid, hence, specifying the type and sequence of amino acids for protein synthesis.


The sequence of amino acids in a protein determines its structure and function. The DNA code is a triplet code. Each triplet, a group of three bases, codes for a specific amino acid: the triplet of bases on the DNA and mRNA is known as a codon.

Stop Codons

a nucleotide triplet within messenger RNA that signals a termination of translation. Proteins are based on polypeptides, which are unique sequences of amino acids

Methionine (AUG)

Contains the SCH3 group that can act as a methyl donor (see s adenosyl methionine). Common in proteins but at low frequency. The met x linkage is subject to specific cleavage by cyanogen bromide.


A sequence of three adjacent nucleotides located on one end of transfer RNA. It bounds to the complementary coding triplet of nucleotides in messenger RNA during translation phase of protein synthesis.


A step in protein biosynthesis wherein the genetic code carried by mRNA is decoded to produce the specific sequence of amino acids in a polypeptide chain. The process follows transcription in which the DNA sequence is copied (or transcribed) into an mRNA.

Polypeptide Chain

a single linear chain of many amino acids, held together by amide bonds. A protein is one or more polypeptide (more than about 50 amino acids long)