Biological Molecules- Enzyme Action Flashcards
What are enzymes?
Biological catalysts and proteins
What do enzymes do?
Catalyse metabolic reactions and affect structures in an organism
Where can enzyme action happen?
Within cells (intracellular) or outside cells (extracellular)
What does an enzyme have?
An active site with a specific shape where the substrate molecule binds to
Why are enzymes highly specific?
Due to their tertiary structure
What is activation energy?
The minimum amount of energy that needs to be supplied to chemicals before reaction can happen
How do enzymes lower activation rate?
By making reactions happen at a lower temperature which speeds up the rate of reaction
What happens when a substrate fits into the active site?
Forms an enzyme-substrate complex
How is activation energy lowered when an enzyme-substrate complex is formed?
- Two substrate molecules may need to be joined so being attached to the enzyme holds them close together and reduces any repulsion between the molecules so they can bind more easily
- Catalysing a breakdown reaction, fitting into active site puts a strain on the bonds in the substrate so it breaks up more easily
What is the lock and key model?
Substrate fits into the active site exactly the same way a key fits into a lock
What is the induced fit model?
The active site changes shape slightly when the substrate binds
How do enzyme properties relate to their tertiary structure?
- Enzymes are very specific
- Only one complementary substrate will fit the active site
- Shape of active site determined by tertiary structure
- Different enzymes have different tertiary structures and a different active site shape
- Shape of active site will change if tertiary structure is altered
- Tertiary structure may be altered by pH or temperature changes
- If mutation occurs in primary structure, tertiary structure will change
