Which of the following is false? a. an apoenzyme can catalyze its reaction without its cofactor b an organic cofactor can be called a coenzyme c. metal ions often act as cofactors d. a metal ion cofactor can be bound directly to the enzyme or to a coenzyme

Option (a) is the correct answer.

Explanation:

A protein part of an enzyme is known as an apoenzyme. An apoenzyme combines with a cofactor, it is known as holoenzyme.

Without a cofactor an apoenzyme cannot function as cofactor helps in the formation of an active enzyme system and provides a specific site on enzyme for the substrate.

Whereas a non-protein chemical compound or metal ion that helps in the activity of enzyme as a catalyst is known as a cofactor. A metal ion cofactor can be bound directly to the enzyme or to a coenzyme.

The organic non-protein molecules which bind to the protein molecule to form an active enzyme is known as a coenzyme. Coenzymes are small size molecules which help the enzymes to act as a catalyst.

Therefore, we can conclude that the statement an apoenzyme can catalyze its reaction without its cofactor, is false.

the density of gold = 19.3 g/cm3

the relation between density and mass and volume is

density = mass / volume

given :

mass of gold = 13 g

density = 13g / volume = 19.3

volume = 13 /19.3 = 0.67 cm^3

thus volume of gold nugget = 0.67 cm^3