Chemical reactions convert to . In nonliving systems, the presence of a(n) allows the reaction to proceed very quickly and have a lower . In living systems, this function is carried out by proteins called .

reactants, products

catalyst

activation energy

enzymes

Chemical reactions convert reactants to products. In nonliving systems, the presence of a(n) catalyst allows the reaction to proceed very quickly and have a lower activation energy. In living systems, this function is carried out by proteins called enzymes.

the sugar-phosphate backbone forms the structural framework of nucleic acids, including dna and rna. this backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.