Cell Structure & Organelles MCQs with Answers

Enzymes have a 3D shape due to which type of protein structure?

• A.Primary structure
• B.Secondary structure
• C.Tertiary structure
• D.Quaternary structure

Enzymes catalyze chemical reactions by _ the activation energy.

• A.Lowering
• B.Increasing
• C.Stabilizing
• D.Neutralizing

Enzymes show optimum activity between 37°C to 50°C; however, they:

• A.Continue working normally above 50°C
• B.Become more active above 50°C
• C.Lose activity permanently above 50°C
• D.Regain activity upon cooling below 37°C

When temperature rises above the optimum temperature, the rate of reaction decreases rapidly due to _?

• A.pH alteration
• B.Substrate depletion
• C.Product inhibition
• D.Enzyme denaturation

The first carbon compound which enters Krebs cycle is _?

• A.Pyruvic acid
• B.Oxaloacetic acid
• C.Citric acid
• D.Acetyl Co-A

Small portion of enzyme where substrate attach with enzyme called _?

• A.Active site
• B.Binding pocket
• C.Catalytic domain
• D.Receptor region

What will happen with the addition of salt to water?

• A.Osmotic potential will increase
• B.Osmotic potential will decrease
• C.Water potential will increase
• D.Both osmotic and water potential will increase

Percentage of lipids in cell membrane is ?

• A.20-30%
• B.40-50%
• C.60-70%
• D.80-90%

Which one of the following is the end product of glycolysis?

• A.Acetyl CoA
• B.Pyruvic acid
• C.Citric acid
• D.Lactic acid

What happens to the enzyme after an enzyme-catalysed reaction?

• A.It is permanently destroyed
• B.It is converted into a product
• C.It is used for another reaction
• D.It loses its catalytic ability forever