Transcription and translation

The DNA is divided into genes, which contain instruction for making proteins that make up a human. Thus, the instructions from genes in the DNA are used to make proteins. This process is called the central dogma, and it is divided into transcription and translation (described below:))

TRANSCRIPTION: Transcription occurs in the nucleus. The DNA is like a cookbook full of different recipes (genes/segments of DNA) that contain instructions about how to make proteins. Thus, if we want to make a protein, we need to copy the recipe (information in a gene) in the DNA. This is what transcription is all about.

An enzyme called RNA polymerase moves down the DNA and copies the information in it. The transcript of this information is called the messenger RNA (mRNA). However, we need to alter it a little bit before it can leave the nucleus. We need to add 5′ cap and poly(A) tail, and we must get rid of parts that don’t code for a specific amino acid.

TRANSLATION: Translation occurs in the cytoplasm. When the mRNA leaves the nucleus, it enters a ribosome. The ribosomes are protein factories. The mRNA moves through the ribosome. The amino acids that are needed to make the protein are brought by transfer RNA (tRNA). There are many types of tRNA, and each type attaches to a specific amino acid.

The tRNA attaches to the codon (three nucleotides that code for specific aminoacids) on the mRNA, and leaves the amino acid (see the picture below). This way, amino acids are bonded together, forming a polypeptide chain (a protein). This protein is later used in our body.

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