Explain how amino acids form proteins.

Amino acids are the building blocks of proteins, and they combine through a series of steps:

1. Amino acids are organic compounds composed of an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom, and a distinctive side chain attached to a central carbon atom (also known as the alpha carbon).

2. The formation of proteins from amino acids is called protein synthesis. This process primarily involves two types of reactions: transcription and translation, and it occurs in the following sequence:

a. Transcription: In the cell nucleus, the DNA sequence of a gene is transcribed to produce messenger RNA (mRNA).

b. Translation: The mRNA is transported from the nucleus to the cytoplasm, where the ribosomes read the mRNA sequence and translate it into a specific sequence of amino acids.

3. The actual linkage of amino acids occurs through a dehydration synthesis reaction known as a peptide bond. During this reaction, the amino group of one amino acid reacts with the carboxyl group of another, releasing a molecule of water (H2O) and forming a covalent bond.

4. As the ribosome moves along the mRNA, it continues to add new amino acids to the growing chain in the order dictated by the mRNA code, forming a polypeptide chain.

5. As more peptide bonds are formed, the sequence of amino acids becomes a polypeptide. The sequence in which amino acids are arranged in a protein is determined by the sequence of nucleotide bases in the gene that encodes for that protein.

6. Once the full length polypeptide chain is synthesized, it undergoes folding into a specific three-dimensional structure, which is determined by the interactions among the amino acid side chains.

7. The final three-dimensional structure of the protein is crucial for its function, and in many cases, multiple polypeptides will further assemble into larger protein complexes.