Solved MCQs of Biology Class 9 Chapter 6

When an enzyme is no longer able to work, it is said to be:

Catalyzed

Dead

Cofactored

Denatured

The substance on which an enzyme act is called:

Cofactor

Inhabitor

Coenzyme

Substrate

Catabolism constitutes …………….. processes.

Constructive

Destructive

Both a & b

None

What is true about cofactors?

Break hydrogen bonds in proteins

Help facilitate enzyme activity

Increase activation energy

Are composed of proteins

Lock and key model was proposed by …………….. .

Emil Fisher

Koshland

Freitz London

None

Pepsin works at the PH of …………… .

1

2

3

4

Which one of the following is specific in action ?

Catalyst

Enzyme

Both

None

Which enzyme breaks the peptide bods:

Amylase

Protease

Lipase

None

The molecule that fits the active sites that is called:

Substrate

Enzyme

Catalyst

All

When we add more substrate to an already occurring enzymatic reaction and there is no increase in the rate of reaction, what would you predict?

All active site have been occupied by substrate molecules

The enzyme molecule have denatured

More substrate acted as inhibitor

More substrate has disturbed the pH of the medium