Describe what happens at each stage of the 2 stages of protein synthesis and say where each occurs?

The first stage of protein synthesis is transcription. The DNA helix is untwisted by the enzyme dna helixase. Then the DNA is split into two as the hydrogen bonds are broken between the complementary base pairs. Then a mRNA strand is made with complementary pairs, much like with DNA replication. However this mRNA strand leaves the nucleus via the nuclear pores. The second step of protein synthesis is translation, which occurs in the cytoplasm and requires ribosomes. A small ribosomal subunit attaches to the bottom of the mRNA strand, and a large ribosomal subunit to the top of the mRNA. Then the synthesis can begin. For it to start the first codon (base triplet) must be methionine (AUG.) Then the anticodons on a tRNA with an amino acid comes into the large ribosome unit and matches with a codon. The first anticodon must be (UAC) because it is complementary to AUG. Then the next anticodon comes along. Before the tRNA leaves the ribosome polmerase creates a peptide bond between the amino acids. Then the tRNA leaves the ribosome, leaving the amino acid behind. This process repeats itself until it reaches a stop codon. Then the amino acid chain (polypeptide) is released into the cytoplasm as a protein when the ribosome and mRNA separate. This protein is in its primary structure (the arrangement.) It can then assume its secondary structure (alpha helix or beta pleated sheet.) Then tertiary 3d precise shape (globular of fibrous.)

Transcription: In the nucleus, an RNA copy (mRNA transcript) of a gene is produced Translation : In the cytoplasm, ribosomes attach to the mRNA and move down it, translating 3 consecutive bases into a single amino acid, join the amino acids together into the protein molecule.

Transcription: In the nucleus, an RNA copy (mRNA transcript) of a gene is produced Translation : In the cytoplasm, ribosomes attach to the mRNA and move down it, translating 3 consecutive bases into a single amino acid, join the amino acids together into the protein molecule.