Question

Part A - Overview of enzyme structure and enzymatic reactions Enzymes are large globular proteins. Much of their three dimensional shape is the result of interactions between the R (variable) groups of their amino acids. The active site is the portion of the enzyme that will interact with the substrate the molecule that the enzyme acts upon. The nature and arrangement of amino acids in the active site make each enzyme specific to a substrate and to the reaction it will catalyze Substiate Active site Enzyme Enzyme substrate complex View this animation on binding specificity Most enzyme names end inase after the molecule it catalyzes for example, breakdown of the dissacharide sucrose (table sugar) is catalyzed by sucrase When an onzyme binds to the appropriate substrate subtle changes occur in the shape of the active site. This alteration of the active site is known as an inducede Induced it enhances catalys, as the enzyme converts the substrate to products View this animation on induced it For example, sucrose is a very stable molecule, but when a small amount of the enzyme sucrase is added to a sucrose solution, the sucrose is quickly converted to its products the monosaccharides glucose and fructose. This is a typical hydrolysis reaction, which means that a water molecule is added, breaking the chemical bond between the monomers Once the products are released the enzyme is restored to its original form, and it can continue to catalyze the same type of reaction over and over as long as substrate molecules are present

Answer 1

The correct option is

A) The enzyme lowers the activation energy of the reaction.

Most enzymes are proteins with a localized site, called the active site to bind the substrate. Enzymes will remain unchanged while catalyzing the reaction. They speed up the rate of chemical reactions in biological systems by lowering the Gibbs free energy of activation. Enzymes do not affect the Gibbs free energy of a reaction (ΔG) and do not change whether a reaction is exergonic or endergonic.