CHAPTER 4: BIOCATALYSIS

What is the function of hydrolase?

• Catalyse the transfer of functional group from one substrate to the another

• Catalyse the formation of functional group by adding the chemical group

• Catalyse the breakdown of chemical bond by adding water molecules

• Catalyse the addition or removal of a chemical group to substrate

Which of the following statements is NOT the property of an enzyme?

• It is reusable

• Posses active site

• Enzyme is a fibrous protein

• Only a small amount is needed to bring about of large amount of substrates

Substrate bind to enzymes at the

• Active site

• Allosteric site

• Regulatory site

• Substrate-enzyme complex

When the pH value is above or below optimum pH, the enzymatic activity will

• increase

• decrease

• immediately stop

• remain unchanged

Zinc is an essential trace element. It is part of the active site for the enzyme carboxypeptidase. Which of the following is the function of zinc?

• As a non-competitive inhibitor of the enzyme

• As a cofactor necessary for enzyme activity

• As an allosteric activator of the enzyme

• As a coenzyme derived from vitamin

A cofactor is essential to enzyme as it is able to

• increase the concentration of substrate

• decrease the effect of extreme pH and temperature to enzyme

• bind and change enzyme’s active site to become complement with substrate

• bind tightly to enzyme’s active site to protect the enzyme from damaged

Enzymes that do not have cofactors known as

• Holoenzymes

• Apoenzymes

• Protoenzymes

• Proenzymes

Which of the following statement is true regarding enzyme inhibition?

• It may be reversible but never irreversible

• Reversible inhibitor may compete with substrate to bind at enzyme’s allosteric site

• Irreversible inhibitor can bind to active site, allosteric site or any part of enzyme resulting permanent

      damage

• Non-competitive inhibition can be overcome by increasing substrate concentration

The rate of enzyme activity will decrease if some of the active site occupied by competitive inhibitor. What should you do to overcome this matter?

• Add more enzymes

• Add more substrates

• Heat the solution

• Just wait and see

Why the transmission of electron in ETC will block and disturbing the synthesize of ATP in the presence of cyanide?

• Cyanide act as electron acceptor

• Cyanide act as reversible inhibitor

• Cyanide act as impurities

• Cyanide act as irreversible inhibitor