Module 2, section 4: Enzymes, and enzyme action.

What is the difference between an intracellular and extracellular enzyme, and give examples for both?

Intracellular enzymes work inside cells, and an example is rubisco.

Extracellular enzymes work outside cells, and an example is pepsin.

What are the four factors that affect enzyme activity, and describe HOW they affect enzymes.

1. Temperature. Give enzymes and substrate more energy, meaning collision is more likely.

2. pH. pH changes can cause enzymes to denature because H+ and OH- ions can break ionic bonds that keep enzymes in their shape.

3. Increasing enzyme concentration. This again increases frequency of substrate enzyme collisions. However, rate then levels off when enzyme conc. is no longer the limiting factor.

4. Increasing substrate concentration. Increases frequency of collisions. Only to a point though because all active sites become filled.

What’s the temperature coefficient?

Describes how the rate changes when temperature is increased by 10 degrees celsius.

q10= rate at higher temp/rate at lower temperature.

What are the two types of cofactors, and what do they do?

Inorganic and organic (coenzymes). They help the bind substrate and the enzyme together.

How are coenzymes different to cofactors?

Coenzymes are used up in a reaction, and are chemically regenerated later on, cofactors are not used up at all.

What is the source of coenzymes?

They often come from vitamins

What is the cofactor for amylase?

Chloride ions.

What is end product inhibition?

When a product formed inhibits the enzyme that was just catalysing the reaction.