Enzymes-Cellular_Respiration

Enzyme

A protein that acts as a biological catalyst, not consumed by the reaction.

Enzyme-substrate complex

The temporary complex formed when an enzyme binds to its substrate.

Activation energy (EA)

The amount of energy needed for reactants to reach the transition state.

Transition State

An unstable state where reactants must reach before products are formed.

Allosteric Enzymes

Enzymes made up of multiple polypeptides with a regulatory site for an inhibitor or activator.

Competitive Inhibition

Inhibition that occurs when a substrate resembling the enzyme's substrate competes for the active site.

Noncompetitive Inhibition

Inhibition that occurs when an inhibitor binds to another part of the enzyme, changing its shape.

Induced Fit Model

A model where enzyme structure is flexible, changing shape upon substrate binding to enhance catalysis.

Substrate specificity

The specific interaction between an enzyme and its unique substrate.

Energy Barrier

The barrier that determines the rate of a reaction, represented by the activation energy.

Irreversible Inhibition

Inhibition that permanently deactivates an enzyme, e.g., nerve gas or penicillin.

Feedback Inhibition

Process where the end product of a metabolic pathway inhibits an enzyme involved in its synthesis.

Active Site

The specific region of an enzyme where substrate binds and reaction occurs.

What is specific binding of substrate to active site?

The precise interaction where a substrate binds to the active site of an enzyme due to complementary shapes and charges.

What does the induced fit model suggest?

The enzyme adjusts its shape to accommodate the substrate upon binding, enhancing the catalytic activity.

What is the transition state in enzymatic reactions?

An unstable state during a chemical reaction where reactants are converted into products, characterized by a peak in potential energy.

How do enzymes lower activation energy (EA)?

Enzymes provide an alternative reaction pathway, stabilizing the transition state and thus reducing the energy required for the reaction.

What is the energy profile of an enzyme-catalyzed reaction compared to an uncatalyzed reaction?

The energy profile of an enzyme-catalyzed reaction shows a lower activation energy peak compared to that of an uncatalyzed reaction, resulting in a faster reaction rate.

How can enzymes be regulated by molecules?

Enzymes can be regulated by molecules, known as regulators, that can either activate the enzyme or inhibit its activity by binding to the active site or an allosteric site.

What is competitive inhibition?

A type of inhibition where an inhibitor competes with the substrate for binding at the active site of the enzyme.

What is non-competitive inhibition?

A type of inhibition where an inhibitor binds to an allosteric site on the enzyme, changing its shape and functionality without competing for the active site.

What is reversible inhibition?

Reversible inhibition is a type of enzyme inhibition that can be reversed by increasing substrate concentration or removing the inhibitor that binds non-covalently to the enzyme.

What is an example of allosteric regulation in biochemical pathways?

An example of allosteric regulation is the regulation of cellular respiration or the production of isoleucine from threonine, where end products can inhibit the activity of enzymes in the pathway.

What is the difference between activation and inhibition of enzymes?

Activation increases an enzyme's activity, allowing it to catalyze reactions more efficiently, while inhibition decreases its activity and can prevent the enzyme from catalyzing reactions.

How do enzymes catalyze reactions?

Enzymes catalyze reactions by lowering the activation energy, stabilizing the transition state, and providing an active site for the substrate to bind, which facilitates the reaction.

What is the difference between the active site and the induced fit model?

The active site is the specific region of the enzyme where the substrate binds and the reaction occurs, while the induced fit model suggests that the enzyme's structure is flexible and changes shape upon substrate binding to optimize the catalytic process.