LIFE SCIENCE

Detailed explanation-1: -A fundamental task of proteins is to act as enzymes-catalysts that increase the rate of virtually all the chemical reactions within cells. Although RNAs are capable of catalyzing some reactions, most biological reactions are catalyzed by proteins.

Detailed explanation-2: -In a chemical reaction, atoms do not change; what changes are the bonds between them. Most chemical reactions occur in aqueous solutions. They can be reversible if the products become reactants again, or irreversible when the products do not go back to being the reactants that gave rise to them.

Detailed explanation-3: -Proteins are made up of amino acids. Proteins carry out most of the chemical activity in cells.

Detailed explanation-4: -A catalyst is a substance that speeds up a chemical reaction, or lowers the temperature or pressure needed to start one, without itself being consumed during the reaction. Catalysis is the process of adding a catalyst to facilitate a reaction.

Detailed explanation-5: -The elements that are present in the highest quantities in living organisms are oxygen, carbon, hydrogen, nitrogen, sulfur, and phosphorus. These elements make up about 99% of their living mass.