Enzyme Activity and Inhibition Concepts

The video tutorial by Mikey from Evo Prep Academy covers enzymes, focusing on their role in reducing activation energy in chemical reactions. It explains the induced fit model, factors affecting enzyme activity, and types of enzyme inhibitors. The tutorial also discusses negative feedback inhibition using threonine and isoleucine as examples.

What is the primary role of enzymes in chemical reactions?

• To decrease the activation energy

• To make reactions endothermic

• To increase the activation energy

• To change the products of the reaction

Which of the following is NOT a way enzymes reduce activation energy?

• Orienting substrates properly

• Straining substrate bonds

• Increasing the temperature of the reaction

• Creating a favorable microenvironment

How does the induced fit model differ from the lock-and-key model?

• The enzyme changes shape to fit the substrate

• The substrate changes shape to fit the enzyme

• Both the enzyme and substrate remain rigid

• The enzyme is destroyed after the reaction

What happens to an enzyme when it is denatured?

• It becomes a different enzyme

• Its structure is altered, losing function

• It becomes more active

• It speeds up the reaction

Which factor does NOT affect enzyme activity?

• Temperature

• Color of the enzyme

• pH

• Salinity

What is the role of competitive inhibitors in enzyme activity?

• They permanently deactivate the enzyme

• They compete with the substrate for the active site

• They increase the enzyme's activity

• They bind to the allosteric site

How do non-competitive inhibitors affect enzyme activity?

• They bind to the active site

• They change the enzyme's shape by binding elsewhere

• They increase substrate concentration

• They remove the substrate from the enzyme

What is the purpose of negative feedback inhibition in metabolic pathways?

• To speed up the entire pathway

• To increase the production of the end product

• To prevent the overproduction of the end product

• To destroy the initial substrate

In the example of threonine and isoleucine, what role does isoleucine play?

• It is the initial reactant in the pathway

• It acts as a substrate for threonine

• It inhibits the enzyme threonine deaminase

• It speeds up the conversion of threonine

What happens when isoleucine levels are low in the cell?

• Threonine deaminase is inhibited

• The pathway is shut down permanently

• Isoleucine is converted back to threonine

• Threonine is converted to isoleucine