9th Biology Chapter6 Enzymes

Question 1. Describe the Induced Fit Model of Enzyme Action.
Answer:

The induced fit model proposes that the active site of an enzyme is not rigid but can undergo conformational changes upon substrate binding. In this model, the enzyme’s active site initially has a shape that is not perfectly complementary to the substrate. However, when the substrate binds, the enzyme undergoes a conformational change to accommodate the substrate, resulting in optimal binding and catalysis.

Question 2. How Does pH Affect Enzyme Activity?
Answer:

Enzymes have an optimal pH at which they exhibit maximum activity. Changes in pH can alter the charge distribution on the enzyme’s active site, affecting its ability to bind to substrates and catalyze reactions. Extreme pH levels can denature enzymes, leading to a loss of activity.

Question 3. What is Enzyme Specificity and Why is it Important?
Answer:

Enzyme specificity refers to the ability of an enzyme to selectively bind to specific substrates and catalyze specific chemical reactions. This specificity ensures that enzymes can efficiently perform their biological functions without interacting with non-target molecules.

Question 4. Explain the Lock and Key Model of Enzyme Action.
Answer:

The lock and key model describes the interaction between enzymes and substrates as a perfect fit, where the substrate (key) fits precisely into the enzyme’s active site (lock). According to this model, the active site of the enzyme is rigid and complementary in shape to the substrate, allowing for specific binding and catalysis.

Question 5. Explain How the Shape of Enzymes Contributes to Their Specificity.
Answer:

The specificity of enzymes is primarily due to their unique three-dimensional shapes, particularly the shape of their active sites. The active site is a pocket or crevice on the enzyme’s surface that precisely accommodates the shape and chemical properties of the substrate. This complementary fit between the enzyme’s active site and the substrate ensures specific binding and catalysis of the intended reaction.

Question 6. Describe the Influence of Substrate Concentration on Enzyme Activity.
Answer:

Enzyme activity increases with substrate concentration up to a certain point, known as the saturation point. At low substrate concentrations, increasing substrate concentration leads to a proportional increase in enzyme activity as more active sites become occupied. However, at high substrate concentrations, all enzyme molecules are already bound to substrates, and further increases in substrate concentration do not increase the rate of reaction.

Question 7. How does temperature affect the energy of activation?
Answer:

Increasing temperature generally increases the kinetic energy of particles, making it easier to overcome the energy of activation and speed up the reaction.

Question 8. Is the energy of activation different for every chemical reaction?
Answer:

Yes, each chemical reaction has its specific energy of activation, determined by the nature and complexity of the reaction.

Question 9. Explain the Effect of Temperature on Enzyme Activity.
Answer:

Enzyme activity is influenced by temperature, with each enzyme having an optimal temperature at which it functions most efficiently. Low temperatures decrease enzymatic activity due to slower molecular motion, while high temperatures can denature enzymes, disrupting their structure and activity.

Question 10. What role do catalysts play in relation to the energy of activation?
Answer:

Catalysts lower the energy of activation, making it easier for the reaction to occur without being consumed in the process.

Question 11. What units are used to measure the energy of activation?
Answer:

The energy of activation is typically measured in joules (J) or kilojoules per mole (kJ/mol).

Question 12. What is the Mechanism of Enzyme Action?
Answer:

Enzymes catalyze chemical reactions by lowering the activation energy required for the reaction to occur. They do this by binding to specific substrates at their active sites and facilitating the formation of transition states, which leads to the conversion of substrates into products.

Question 13. What are Enzymes and What are Their Characteristics?
Answer:

Enzymes are biological catalysts that speed up chemical reactions in living organisms without being consumed in the process. They are usually proteins that possess specific three-dimensional structures, which allow them to bind to substrates and facilitate chemical reactions.

Question 14. What Factors Affect Enzyme Activity?
Answer:

Several factors can affect enzyme activity, including pH, temperature, substrate concentration, enzyme concentration, and the presence of inhibitors or activators.

Question 15. Explain how enzymes influence the energy of activation in biological reactions.
Answer:

Enzymes act as biological catalysts, lowering the energy of activation and facilitating biochemical reactions in living organisms.

Question 16. What is the energy of activation in a chemical reaction?
Answer:

The energy of activation is the minimum amount of energy required for a chemical reaction to occur.

Question 17. Define Energy of Activation and its Role in Enzyme Catalysis.
Answer:

Energy of activation is the energy required to initiate a chemical reaction. Enzymes lower the energy of activation, making it easier for reactions to occur by stabilizing the transition state of the reaction. This accelerates the rate of reaction without changing the overall free energy change.

Question 18. Why is Enzyme Specificity Important for Biological Processes?
Answer:

Enzyme specificity is crucial for maintaining the efficiency and accuracy of biological processes in living organisms. By selectively binding to specific substrates, enzymes can regulate metabolic pathways, control the flow of biochemical reactions, and ensure the proper functioning of cellular processes. Without specificity, enzymes would catalyze indiscriminate reactions, leading to chaos and dysfunction within cells.

Question 19. Can a higher concentration of reactants affect the energy of activation?
Answer:

Generally, a higher concentration of reactants does not affect the energy of activation; it mainly depends on factors like temperature and catalyst presence.

Question 20. Why is energy of activation needed in a reaction?
Answer:

It is needed to overcome the energy barrier and initiate the reaction by breaking the chemical bonds in the reactants.