Question

Describe how protein is synthesized from a strand of DNA to a polypeptide chain Please included the following terms in your response: base pairs, 5', 3', complementary strand, RNA polymerase, mRNA, rRNA, tRNA, amino acid, codon, anticodon, and peptide bond.

Answer 1

Protein synthesis consists of a series of steps ranging from the transcription of DNA to messenger RNA (mRNA), to the coupling of this to transfer RNA (tRNA) and ribosomes to produce polypeptide chains by the addition of amino acids.

Step-by-step explanation:

DNA is a molecule present in the nucleus of the cell, formed by a double complementary strand that is linked by specific sequences of nitrogenous base pairs. This sequential order contains the organized genetic information of a species.

1. The first step in protein synthesis occurs in the nucleus, through the transcription of DNA into mRNA, in which a single strand of mRNA is formed from the sequence of nitrogenous bases, with the help of the enzyme RNA polymerase. This transcription also includes the synthesis of tRNA and ribosomal RNA. Transcription occurs in the 5' → 3' direction of the DNA strand.
2. Once the different RNA molecules have been synthesized, the next step occurs in the cell's cytoplasm, with the binding of the mRNA to the minor subunit of the ribosome. In the sequence of nitrogenous bases in mRNA, a triplet of bases is called a codon -the base of the genetic code- each of which will encode a specific amino acid.
3. To the complex formed by mRNA and minor subunit of the ribosome a tRNA is coupled, which contains the anticodon that determines this coupling, in addition to the amino acid it encodes. This is the moment when the major subunit of the ribosome is attached and protein synthesis begins.

Each of the amino acids will be linked to others by peptide bonds -following the sequence of codons in the RNA- until synthesis stops with the appearance of the stop codons.