What Are the Steps of Protein Synthesis​?

In case you have ever wondered "What are the steps of protein synthesis​?", you have come to the right page! In this article, you can learn all about how genetic information translates into functioning proteins 🧬✨. Read on to learn more about:

• The protein biosynthesis steps​;
• All steps of protein formation​; and
• Transcription and translation​.

Let's begin with the basics — what is protein synthesis​?

Protein synthesis is one of the most fundamental processes in all living organisms, where the information encoded in our DNA is decoded and translated into a sequence of amino acids. Each triplet of genetic bases corresponds to a specific amino acid. In this way, genetic sequences build chains of amino acids that fold into functional proteins. You could say that your DNA is the recipe, and protein synthesis is the process that turns it into fully "baked" proteins, ready to carry out essential life functions 📜🥣.

Each protein consists of a unique composition of amino acids, which conveys each protein its specific function. The human cell is estimated to contain approximately 10 billion proteins! That's a lot, but humans are extraordinarily complex, and our bodies perform trillions of tasks simultaneously. There are alone 30-40 proteins (mostly enzymes) involved in digestion, and up to 300 proteins involved when actively fighting a viral infection, not to mention the millions of distinguished proteins that make up a mature immune system.

In essence, protein synthesis turns your genetic code into the proteins that fuel everything your body does 🔋⚡.

Now, let's delve deeper into the protein biosynthesis steps to fully understand what is happening on a molecular level 🔎.

So, what are the steps of protein synthesis exactly? Even though there are a series of smaller steps, protein synthesis can be divided into two main steps — transcription and translation​.

Transcription

The first step of protein synthesis is the transcription of DNA to messenger RNA (mRNA) in the nucleus. This means that our two-stranded spiral DNA provides a template for the newly generated mRNA, which contains complementary nucleotides.

The steps of transcription are the following:

1. Initiation — RNA polymerase binds to the promoter region of DNA, separates the strands, and begins synthesizing RNA;
2. Elongation — RNA polymerase moves along the DNA, adding complementary ribonucleotides to the growing RNA strand;
3. Termination — RNA synthesis stops when a termination signal or sequence is reached on the DNA; and
4. mRNA processing (only in eukaryotes) — introns (non-coding regions) are removed and exons (encoding regions) are put together, and a protective 5' cap and poly-A tail are added, after which the mRNA leaves the nucleus.

Translation

Translation occurs at the ribosomes in the cytoplasm, where the newly synthesized mRNA is translated into a protein. The steps are named the same as in transcription, but are different:

1. Initiation — mRNA attaches to the ribosome with the start codon (AUG), which initiates translation by transfer RNA (tRNA) carrying the first amino acid methionine to bind to the codon.
2. Elongation — each codon on the mRNA is recognized by a complementary anticodon on a tRNA molecule, adding its amino acid to the growing polypeptide chain.
3. Termination — when a stop codon (UAA, UAG, or UGA) is reached, the translation ends, and the new protein is released.
4. Protein folding and post-translational modifications — to be functional, the protein must be folded into its unique three-dimensional shape, and some proteins also undergo post-translational modifications like the addition of sugar and phosphate groups or lipid chains.