role of enzymes

Question 1

what are enzymes? what do they do?

Answer 1

• proteins that act as biological catalysts for intra and extracellular reactions to determine structure and function, and therefore affect metabolism of cells and whole organism
• specific tertiary structure determines shape of active site, complementary to a specific substrate
• formation of enzyme substrate complexes (ESC) lowers activation energy of metabolic reactions

Question 2

give an example of an enzyme that catalyses intracellular reactions

Answer 2

catalase: catalyses decomposition of hydrogen peroxide (which causes oxidative stress) into water + oxygen

Question 3

give 2 examples of enzymes that catalyse extracellular reactions

Answer 3

amylase: carbohydrase catalyses digestion of starch to maltose in saliva / small intestine lumen
trypsin: pancreatic endopeptidase catalyses hydrolysis of peptide bonds small intestine lumen