biology MCQs - 9th class Chapter 07 Mcqs

1

What is the sum of all chemical reactions that occur within an organism to sustain life?

A

Anabolism

B

Catabolism

C

Metabolism

D

Respiration

2

Which process involves the breakdown of complex molecules into simpler ones, releasing energy?

A

Anabolism

B

Photosynthesis

C

Metabolism

D

Catabolism

3

Which of the following is an example of anabolism?

A

Cellular respiration

B

Protein synthesis

C

Lipolysis

D

Digestion of food

4

What are enzymes predominantly made of?

A

Carbohydrates

B

Lipids

C

Nucleic acids

D

Proteins

5

Which term describes enzymes that operate within the cells where they are produced?

A

Extracellular enzymes

B

Intracellular enzymes

C

Coenzymes

D

Prosthetic groups

6

The non-protein molecules required for some enzymes to be fully active are called?

A

Substrates

B

Products

C

Cofactors

D

Inhibitors

7

Inorganic cofactors typically include:

A

Vitamins

B

Metal ions

C

Nucleotides

D

RNA molecules

8

Which organic cofactors are tightly bound to the enzyme?

A

Coenzymes

B

Prosthetic groups

C

Metal ions

D

Substrates

9

NAD and NADP are examples of which type of molecule?

A

Prosthetic groups

B

Inorganic cofactors

C

Coenzymes

D

Enzymes

10

In which industry are protease and amylase enzymes used to remove stains?

A

Food industry

B

Paper industry

C

Biological detergent industry

D

Fermentation industry

11

The specific region on an enzyme where the substrate binds is called the:

A

Catalytic region

B

Allosteric site

C

Active site

D

Binding pocket

12

Who proposed the 'Lock and Key Model' of enzyme action?

A

Daniel Koshland

B

Louis Pasteur

C

Emil Fischer

D

Robert Hooke

13

According to the Induced Fit Model, what happens when a substrate binds to an enzyme?

A

The substrate changes shape

B

The enzyme's active site is reshaped

C

The enzyme denatures

D

The product is released immediately

14

What is the optimum temperature for most human enzymes?

A

27°C

B

37°C

C

47°C

D

98°C

15

What happens to an enzyme when the temperature is raised well above the optimum level?

A

It works faster

B

Its globular structure is lost

C

It becomes more specific

D

It gains new active sites

16

The loss of an enzyme's globular structure due to extreme heat or pH is called:

A

Saturation

B

Inhibition

C

Activation

D

Denaturation

17

Pepsin, an enzyme in the stomach, works best in what type of medium?

A

Acidic medium

B

Alkaline medium

C

Neutral medium

D

Slightly acidic medium

18

What is the optimum pH for the enzyme trypsin?

A

1.5 - 2.0

B

4.0

C

7.0

D

7.8

19

What happens to the rate of reaction when all active sites of an enzyme are occupied by substrate molecules?

A

It increases exponentially

B

It stops completely

C

It does not increase further

D

It decreases rapidly

20

This state, where all active sites are occupied, is known as:

A

Denaturation

B

Saturation

C

Inhibition

D

Activation

21

Substances that bind to an enzyme and decrease its activity are called:

A

Substrates

B

Cofactors

C

Products

D

Inhibitors

22

Which type of inhibitor resembles the substrate and competes for the active site?

A

Non-competitive inhibitor

B

Allosteric inhibitor

C

Competitive inhibitor

D

Feedback inhibitor

23

Antibiotics are a common example of which type of inhibitors?

A

Competitive inhibitors

B

Non-competitive inhibitors

C

Irreversible inhibitors

D

Product inhibitors

24

Which type of inhibitor binds to a site on the enzyme other than the active site?

A

Competitive inhibitor

B

Substrate analog

C

Non-competitive inhibitor

D

Transition state inhibitor

25

Heavy metals like mercury are examples of:

A

Competitive inhibitors

B

Coenzymes

C

Prosthetic groups

D

Non-competitive inhibitors

26

Cellular respiration, in which glucose is broken down, is an example of:

A

Anabolism

B

Metabolism

C

Catabolism

D

Photosynthesis

27

Photosynthesis, where CO2 and H2O form glucose, is a form of:

A

Anabolism

B

Catabolism

C

Lipolysis

D

Hydrolysis

28

What are RNA molecules that act as enzymes called?

A

Ribosomes

B

Ribozymes

C

Nucleases

D

Polymerases

29

Where are ribozymes primarily found?

A

Mitochondria

B

Nucleus

C

Cell membrane

D

Ribosome

30

Amylase specifically catalyses the breakdown of what substrate?

A

Protein

B

Lipid

C

Starch

D

Sucrose

31

Enzymes secreted by stomach wall cells to digest food are an example of:

A

Intracellular enzymes

B

Metabolic enzymes

C

Extracellular enzymes

D

Synthetic enzymes

32

The haem group is an example of a:

A

Coenzyme

B

Prosthetic group

C

Inorganic cofactor

D

Substrate

33

Enzymes used to degrade starch to lower viscosity in the paper industry are an example of:

A

Industrial application

B

Metabolic regulation

C

Cellular respiration

D

Enzyme inhibition

34

In the Lock and Key model, the active site has a _________ structure.

A

flexible

B

rigid

C

changing

D

globular

35

The Induced Fit Model was proposed by Daniel Koshland in what year?

A

1894

B

1958

C

1920

D

1972

36

A change in pH can affect the _________ of the amino acids at the active site.

A

sequence

B

number

C

ionization

D

color

37

At a very high substrate concentration, the rate of reaction becomes:

A

zero

B

constant

C

infinitely high

D

negative

38

What do non-competitive inhibitors change?

A

Only the active site shape

B

The overall shape of the enzyme

C

The substrate's shape

D

The reaction's temperature

39

Lipolysis is the breakdown of lipids into fatty acids and what other molecule?

A

Glucose

B

Glycerol

C

Amino acid

D

Water

40

Hummingbirds have one of the highest _________ rates of any animal.

A

respiration

B

anabolic

C

metabolic

D

catabolic

41

Typically, how many amino acids do enzymes contain?

A

10 to 100

B

100 to 1,000

C

1,000 to 10,000

D

Over 10,000

42

The three-dimensional structure of an enzyme is referred to as its:

A

Primary structure

B

Globular structure

C

Linear structure

D

Flat structure

43

Enzymes can speed up reactions ________ of times faster than uncatalyzed reactions.

A

hundreds

B

thousands

C

millions

D

billions

44

In the fermentation industry, yeast uses enzymes to produce:

A

Only simple sugars

B

Different products of human use

C

Only proteins

D

Only starch

45

What is formed when a substrate molecule fits into the active site?

A

Enzyme-product complex

B

Enzyme-inhibitor complex

C

Enzyme-substrate complex

D

Activated enzyme

46

According to the Induced Fit model, the active site is not:

A

Flexible

B

Specific

C

Rigid

D

Catalytic

47

The activity of an enzyme is sensitive to its:

A

size

B

origin

C

environment

D

color

48

What does a non-competitive inhibitor do to the substrate?

A

It helps it bind

B

It does not allow it to fit the changed active site

C

It changes its chemical nature

D

It breaks it down

49

Which process consumes energy?

A

Catabolism

B

Lipolysis

C

Anabolism

D

Cellular respiration

50

Protease enzymes are used in biological detergents to remove which type of stains?

A

Starch stains

B

Fat stains

C

Protein stains

D

Sugar stains