4.c. Sites of enzyme action

Question 1

What are the three distinct sites of enzyme action?

Answer 1

• Extracellular
• Intracellular, in solution
• Intracellular, membrane-bound

Question 2

Where does extracellular enzyme action take place?

Answer 2

Outside of a cell/cells

Question 3

Where does intracellular enzyme action take place?

Answer 3

Inside a cell/cells

Question 4

How do some enzymes end up outside of the cell to catalyse extracellular reactions?

Answer 4

Some enzymes are secreted from cells by exocytosis and catalyse ex. reactions

Question 5

Briefly describe the extracellular action of amylase

Answer 5

Made in salivary gland, moves down salivary glands to mouth

Question 6

How does extracellular enzyme action take place in some fungi and bacteria?

Answer 6

They secrete amylases, lipases, and proteases onto their food to digest it, then absorb the products of digestion

Question 7

How does intracellular enzyme action, in solution, take place in chloroplasts?

Answer 7

Enzymes in solution in the stroma of the chloroplasts catalyse the synthesis of glucose

Question 8

How does intracellular enzyme action, membrane-bound, take place in animal and in plant cells? (2)

Answer 8

• On the cristae of mitochondria and the grana of chloroplasts
• Enzymes help transfer electrons and H+ ions in ATP formation