Enzyme Inhibition and Metabolic Pathways

The video covers enzymes and metabolism, explaining the roles of extracellular and intracellular enzymes. It discusses energy transformation, highlighting the inefficiency and heat loss in cellular reactions. Metabolic pathways, both linear and cyclical, are explored, emphasizing enzyme interactions. The video explains enzyme inhibition, including competitive, non-competitive, and feedback inhibition, and discusses permanent inhibitors like penicillin.

What is the primary difference between extracellular and intracellular enzymes?

• Extracellular enzymes are produced on the rough ER and used outside the cell.

• Extracellular enzymes are produced inside the cell and used inside the cell.

• Intracellular enzymes are produced on the rough ER and used outside the cell.

• Intracellular enzymes are produced on the rough ER and used outside the cell.

Why is heat considered a byproduct in cellular reactions?

• Because it is a form of energy that can be stored for later use.

• Because it is a form of energy that is not usable for cellular processes.

• Because it is a form of energy that can be used for locomotion.

• Because it is a form of energy that can be used for active transport.

What is a characteristic of linear metabolic pathways?

• They have a single enzyme catalyzing all reactions.

• They involve a series of enzymes and intermediate products.

• They do not produce any intermediate products.

• They involve a cycle of reactions.

How does non-competitive inhibition affect an enzyme's active site?

• It changes the shape of the active site, preventing substrate binding.

• It removes the active site from the enzyme.

• It competes with the substrate for the active site.

• It enhances the substrate's ability to bind to the active site.

What happens to the reaction rate when a competitive inhibitor is present?

• The reaction rate remains unchanged.

• The reaction rate decreases initially but can be restored by increasing substrate concentration.

• The reaction rate decreases and cannot be restored.

• The reaction rate increases immediately.

What is feedback inhibition?

• A process where the final product is converted back to the initial substrate.

• A process where the first enzyme inhibits the final product.

• A process where the final product inhibits the first enzyme in the pathway.

• A process where the final product enhances the first enzyme's activity.

How does penicillin act as an inhibitor?

• It enhances bacterial enzyme activity.

• It permanently inhibits a bacterial enzyme necessary for cell wall synthesis.

• It temporarily inhibits a bacterial enzyme necessary for cell wall synthesis.

• It enhances human enzyme activity.

What is the role of threonine in feedback inhibition?

• It acts as a final product that inhibits the first enzyme.

• It acts as an initial substrate that is converted to isoleucine.

• It acts as an enzyme that catalyzes the conversion of isoleucine.

• It acts as a competitive inhibitor for isoleucine.

What is a key feature of permanent inhibitors?

• They can be easily removed from the enzyme.

• They cause temporary changes to the enzyme's active site.

• They enhance the enzyme's activity permanently.

• They cause irreversible changes to the enzyme's active site.

Why are human cells unaffected by penicillin?

• Human cells are resistant to all antibiotics.

• Human cells produce their own penicillin.

• Human cells do not have a cell wall.

• Human cells have a different type of cell wall.