The Six principal categories and their reactions:

Question 1

involve electron transfer

Answer 1

Oxidoreductases

Question 2

transfers a chemical group from one substance to
another

Answer 2

Transferases

Question 3

cleaves the substrate by uptake of a water molecule
(hydrolysis).

Answer 3

Hydrolases

Question 4

forms double bonds by adding or removing a chemical
group

Answer 4

Lyases

Question 5

transfers a group within a molecule to form an isomer

Answer 5

Isomerases

Question 6

couples the formation of various chemical
bonds to the breakdown of a pyrophosphate bond in adenosine
triphosphate or a similar nucleotide

Answer 6

ligases, or synthetases