Enzymes

What is an enzyme?

A biological catalyst that speeds up metabolic reactions without being consumed.

What is the active site?

The region on the enzyme where the substrate binds; it is specific to the substrate.

Why are enzymes specific?

Because their active site has a unique shape that only fits certain substrates.

How do enzymes speed up reactions?

By lowering the activation energy required for the reaction.

What is the lock and key model?

The substrate fits exactly into the enzyme’s active site like a key into a lock.

What is the induced fit model?

The enzyme changes shape slightly to fit the substrate more closely.

What happens to enzymes at high temperatures?

They can denature, losing their shape and function.

What is the effect of pH on enzyme activity?

Each enzyme has an optimal pH; deviations can denature the enzyme.

What happens when substrate concentration increases?

Reaction rate increases until enzymes become saturated.

What happens when enzyme concentration increases?

Reaction rate increases, provided there is enough substrate.

What is competitive inhibition?

An inhibitor that resembles the substrate competes for the active site.

Can competitive inhibition be overcome?

Yes, by increasing substrate concentration.

What is non-competitive inhibition?

An inhibitor binds away from the active site, changing the enzyme’s shape.

Can non-competitive inhibition be overcome by adding more substrate?

No, because it changes the enzyme's shape.

What are immobilized enzymes?

Enzymes attached to an inert material for reuse in industrial processes.

What are advantages of immobilized enzymes?

They are stable, reusable, and do not contaminate products.

What is a disadvantage of immobilized enzymes?

They may have reduced activity or diffusion limitations.

What is adsorption in enzyme immobilization?

Enzymes are physically adsorbed onto inert surfaces like glass beads or clay.

What is an advantage of adsorption?

It is simple, low-cost, and has minimal effect on enzyme activity.

What is a disadvantage of adsorption?

Weak binding can lead to enzyme detachment.

What is covalent bonding in enzyme immobilization?

Enzymes are covalently bonded to supports such as cellulose or silica.

What is an advantage of covalent bonding?

Strong attachment reduces the chance of enzyme loss.

What is a disadvantage of covalent bonding?

May alter the enzyme’s active site and reduce activity.

What is entrapment in enzyme immobilization?

Enzymes are trapped within a gel matrix like alginate beads.

What is an advantage of entrapment?

Enzymes are protected from environmental changes.

What is a disadvantage of entrapment?

Diffusion of substrate/product can slow reaction rate.

What is encapsulation in enzyme immobilization?

Enzymes are enclosed in semi-permeable membranes or microcapsules.

What is an advantage of encapsulation?

Good protection with controlled molecule exchange.

What is a disadvantage of encapsulation?

Membrane diffusion can reduce reaction speed.

What is cross-linking in enzyme immobilization?

Enzymes are chemically linked using agents like glutaraldehyde.

What is an advantage of cross-linking?

Forms highly stable enzyme complexes.

What is a disadvantage of cross-linking?

Complex setup and possible reduction in enzyme activity.