Asequence of dna is altered. explain how this change to the sequence of dna could result in a bioschemical reaction no longer occurring ( for example the breakdown of lactose).
include the following vocabulary: primary structure, tertiary structure, amino acid, active site, substrate, enzyme, mrna.

DNA codes for enzymes (proteins or RNA). And every reaction is controlled by any enzyme.

So, a change in the DNA can result into formation of some non-functional enzyme or a less efficient enzyme or some other protein.

As there's no enzyme for the particular reaction, the reaction wouldn't occur.

Primary structure- It shows the sequence of amino acids in any protein. No role in the functional part of enzyme. 2D structure.

Tertiary structure- It is coiling of enzyme upon itself to form the active or cataytic site. Plays role in catabolic or anabolic function of the enzyme. 3D structure.

Amino acid- As the name goes by, it means a molecule having an amino group (NH2) and an acid group (COOH). Basic building molecules of the proteins.

Active site- The structure formed by the coiling of enzyme (found in tertiary and quaternary structure). This is where the substrate binds to the enzyme

Substrate- This is the molecule which binds to the enzyme and is converted into product by the enzyme.

Enzyme- This is the proteinaceous(sometimes RNA) molecule which accelerates the metabolic functions of our body.

mRNA- This is the molecule formed the DNA present in the nucleus of the cell after transcription. The mRNA carried the information from the DNA present in the cell to form the protein molecule. The basic structural component of this molecule is ribonucleotide molecules.