All Free Biology MCQs with Answers

• A. pH change
• B. Increase of temperature
• C. Oxidizing condition
• D. Dissolving in H2O

Explanation: The deformation or disruption of protein structure under specific conditions is called denaturation of proteins. Denaturation Occurs byHeat changePH changeUndcebrasutgroeng oxidizing or reducing conditions.

• A. Carbon
• B. Hydrogen
• C. Sulphur
• D. Nitrogen

Explanation: All proteins contain the elements carbon, hydrogen, oxygen and nitrogen except sulphur.

• A. Isomerases
• B. Lyases
• C. Transferases
• D. Ligases

Explanation: Isomerases are enzymes that catalyze the rearrangement of atoms within a molecule, converting one isomer into another. They do not necessarily involve the transfer of functional groups between molecules.

• A. Cellulose
• B. Urease
• C. L-asperginase
• D. Lactic dehydrogenase

Explanation: L-asparaginase is the correct option because it is an enzyme used in the treatment of blood cancer in children, particularly acute lymphoblastic leukemia (ALL). L-asparaginase works by depleting the levels of the amino acid asparagine in the blood, which is necessary for the survival of leukemia cells. By depriving the leukemia cells of asparagine, L-asparaginase helps to inhibit their growth and induce apoptosis (cell death).

• A. Oxidoreductases
• B. Hydrolases
• C. Isoenzymes
• D. Isomerases

Explanation: Isoenzymes is the correct option because they are enzymes from the same organism that catalyze the same reaction but are chemically and physically distinct from each other. Isoenzymes often have different kinetic properties, such as substrate affinity or reaction rate, and may be expressed in different tissues or under different conditions.

• A. Enzyme
• B. Substrate
• C. Enzyme and substrate
• D. Enzyme and product

Explanation: The rate of an enzymatic reaction is directly proportional to the concentration of substrate. This is because enzymes catalyze reactions by binding to substrates and converting them into products. When there is more substrate available, there are more opportunities for the enzyme to bind to substrate molecules and catalyze the reaction. However, once all enzyme molecules are saturated with substrate, increasing the enzyme concentration will not further increase the reaction rate. Therefore, the rate of enzymatic reaction is directly related to the concentration of substrate.

• A. [Enzyme]2
• B. [Enzyme]3
• C. [Enzyme]
• D. [√[Enzyme]]

Explanation: The rate of reaction is directly proportional to the square root of the enzyme concentration, represented as [√[Enzyme]]. This relationship is derived from the Michaelis-Menten kinetics equation for enzyme-catalyzed reactions.

• A. Polar site
• B. Cationic site
• C. Active site
• D. Anionic site

Explanation: This is the correct option. The active site is the specific region on the enzyme where the substrate binds and undergoes the catalytic reaction. It has a complementary shape and chemical environment to the substrate.

• A. Apoenzyme
• B. Coenzyme
• C. Cofactors
• D. Both B and C

Explanation: The protein component of the enzyme is called apo-enzyme and the non-protein component is called the co-enzyme. The co-enzyme is also known as co-factor.

• A. Vitamin
• B. Carbohydrate
• C. Lipids
• D. Proteins

Explanation: The group of compounds that is primarily responsible for building of body of an animal and its maintenance is called protein.