Enzyme Action and Models

Dr. Niraj explains the mechanism of enzyme action, focusing on activation energy and two models: the lock and key model by Emil Fischer, which describes a rigid enzyme-substrate fit, and the induced fit model by Koshland, which allows for flexibility in enzyme shape. The video also outlines the steps of enzymatic reactions, emphasizing the formation of enzyme-substrate complexes and the transition state, leading to product formation.

What role does activation energy play in chemical reactions?

• It is the energy released during a reaction.

• It is the energy that stops a reaction.

• It is the energy needed to start a chemical reaction.

• It is the energy required to break down enzymes.

How do enzymes affect activation energy?

• They increase the activation energy.

• They have no effect on activation energy.

• They lower the activation energy.

• They eliminate the need for activation energy.

According to the Lock and Key model, what is the nature of the enzyme's active site?

• It is partially flexible.

• It is rigid and does not change shape.

• It is non-specific to substrates.

• It is flexible and changes shape.

In the Lock and Key model, what does the 'key' represent?

• The product

• The enzyme

• The substrate

• The reaction

What is a key feature of the Induced Fit model?

• The active site is rigid.

• The active site is flexible and adapts to the substrate.

• The enzyme is destroyed after the reaction.

• The substrate changes shape to fit the enzyme.

Who proposed the Induced Fit model?

• Emil Fischer

• Linus Pauling

• Michaelis and Menten

• Daniel Koshland

What is the transition state in an enzymatic reaction?

• The state where the enzyme is inactive.

• The state where the product is formed.

• The state where the substrate is released.

• The state with equal probability of forming product or releasing substrate.

What happens to the enzyme after the reaction is complete?

• It is destroyed.

• It is released as a free molecule and can be reused.

• It is converted into a product.

• It is used up and cannot be reused.

What is formed when an enzyme and substrate combine?

• Enzyme-product complex

• Product

• Transition state

• Enzyme-substrate complex

Which model is more widely accepted for explaining enzyme action?

• Lock and Key model

• Induced Fit model

• Both models are equally accepted

• Neither model is accepted