Zinc, an essential trace element for most organisms, is present in the active site of the enzyme carboxypeptidase. The zinc most
likely functions as a(n)____________. A) competitive inhibitor of the enzyme.
B) noncompetitive inhibitor of the enzyme.
C) allosteric activator of the enzyme.
D) cofactor necessary for enzyme activity.
E) coenzyme derived from a vitamin.
A cofactor is an inorganic ion that is required as an additional chemical component by an enzyme. The ions such as Fe2+, Mg2+, or Zn2+ mostly serve as cofactors for one or more enzymes. The enzymes such as Cytochrome oxidase, catalase, and peroxidase require Fe2+ or Fe3+ ions as a cofactor. Some cofactors are very tightly bound to the active site of their enzymes and their removal renders them enzymes inactive. According to the given information, zinc is present in the active site of the enzyme carboxypeptidase which means that it is a cofactor for this enzyme.
Chemiosmosis is the diffusion of ions through a selective permeable membrane. It specifically refers to the production of ATP through the movement of hydrogen ions through an inner membrane during cellular respiration. Hydrogen ions diffuse from an area of high proton concentration to one of lower concentration.
Like bees and other pollinators, butterflies pick up pollen while they sip a flower's nectar. Once they're off to another plant, the pollen goes with them, helping to pollinate the plant species.
