All Free Biology MCQs with Answers

• A. Becomes fast
• B. Slows down
• C. Remains same
• D. None of these

Explanation: A decrease in the number of resources will lead to more competition between the individuals in a population and hence lead to the death of…

• A. 2
• B. 5
• C. 8
• D. More than 10

Explanation: Option A: There are more than 2 compounds in tar that are involved in causing cancer. The actual number is higher.

• A. Both of them follows
• B. None of them follows
• C. Only b follows
• D. Only a follows

Explanation: Statement a) "He will feel restlessness and anxiety" follows as quitting smoking can lead to withdrawal symptoms such as restlessness and…

• A. Asthma
• B. Tuberculosis
• C. Emphysema
• D. Both Options A and B are correct

Explanation: Emphysema is a lung condition that causes shortness of breath. In people with emphysema, the air sacs in the lungs (alveoli) are damaged.

• A. Amnion
• B. Placenta
• C. Endometrium
• D. Uterus

Explanation: The placenta is defined as temporary intimate mechanical and the physiological connection between foetus and maternal tissue for the…

• A. Morulation
• B. Blastulation
• C. Gastrulation
• D. Organogenesis

Explanation: Germ layers that are ectoderm, endoderm, and mesoderm are formed during gastrulation.

• A. Competitive inhibitor binds to active site
• B. The substrate binds to active site
• C. Enzymes work best in low pH
• D. Both competitive inhibitor binding to alternative site & substrate binding to active site

Explanation: Option C is the incorrect one as enzymes work at optimum pH rather than low pH.

• A. Enzyme is inhibited by the product being produced
• B. Enzyme works normally for regulatory mechanism
• C. Enzyme remains unaffected by product concentration
• D. Enzyme is inhibited irreversibly

Explanation: Feedback regulation of an enzyme occurs when a product of the reaction binds to an allosteric site on the enzyme and affects its catalytic…

• A. Activator
• B. Inhibitor
• C. Substrate
• D. Both A and B

Explanation: Enzymes can be regulated by other molecules that either increase or reduce their activity.

• A. Malonate act as inhibitor
• B. Enzyme shape distorted
• C. Competition for active site
• D. Inactive enzyme gettlng reactivated

Explanation: A noncompetitive inhibitor binds to the enzyme away from the active site, altering the shape of the enzyme so that even if the substrate…

• A. Allosteric site
• B. Active site
• C. Passive site
• D. Regulatory site

Explanation: Non-competitive inhibitors bind to enzymes at allosteric sites, which are distinct from the active site.

• A. Competitive inhibitors
• B. Non-competitive inhibitors
• C. Co-enzymes
• D. Activators

Explanation: Enzymes' productivity is reduced by blocking the active site due to similar shapes, is associated with "competitive inhibitors."…

• A. Increases enzyme activity
• B. Doesn't change enzyme activity
• C. Decreases enzyme activity
• D. None of these

Explanation: An enzyme inhibitor is a molecule that binds to an enzyme and blocks its activity.

• A. Creatinine
• B. Ammonia
• C. Urea
• D. Uric acid

Explanation: Excretion is the removal of chemical waste from the body produced by metabolic processes within cells.

• A. Photosynthesis
• B. Ingesiton
• C. Assimilation
• D. Deamination

Explanation: Nitrogenous wastes are produced as a result of "deamination". The breakdown of amino acids releases nitrogen-containing amine groups…

• A. Ammonotelic
• B. Ureotelic
• C. Uricotelic
• D. None of these

Explanation: Different ways of excreting 1 gram of nitrogen require different amounts of water so they are useful for different kinds of animals.

• A. Detoxifies many chemical poisons
• B. Breaks down ammonia for excretion by the kidneys
• C. Produces urea and uric acids from the nitrogen of amino acids
• D. All of the above

Explanation: The liver is an organ that comes into play after consumption of alcohol, as you can remember excess alcohol consumption can result in…

• A. Enzymes start to denature
• B. Enzymes start to re-nature
• C. Enzymes work best
• D. Enzymes are reactivated

Explanation: Maximum temperature refers to a temperature at which enzymes start to breakdown and denature.

• A. Saturation
• B. Inhibition
• C. Denaturation
• D. Composition

Explanation: Enzymes are protein in nature. At a temperature higher than optimum temperature, the 3D shape of active site denatures and substrate…

• A. Enzyme start denaturing
• B. Enzyme becomes hyperactive
• C. Enzyme work at their best
• D. Inactive enzyme getting reactived

Explanation: Minimum temperature is the term used when an inactive enzyme starts getting reactive.