Enzymes And Digestion Flashcards
What are enzymes?
Enzymes are proteins that act as biological catalysts, speeding up the rare of reactions in the body
Describe the lock and key model
The shape of the substrate is complementary to the active site.
The enzyme is substrate specific
The substrate and enzyme fit tightly together in the active site, forming an enzyme substrate complex
Then the substrate breaks down into two product molecules
What does optimum mean?
Max rate of enzyme activity
What are the factors of affecting enzyme action?
Temperature, pH and enzyme concentration
What happens to the enzyme activity if there is a low-temperature?
Enzyme and substrate have low kinetic energy meaning particles collide less, and fewer Successful collisions – the rate of enzyme activity is low.
What happens to enzyme activity if the temperature is increased?
More kinetic energy, so more collisions, enzyme substrate complexes are formed – increase in the rate of reaction
What happens to enzyme activity at the optimum temperature?
Max number of enzyme substrate complexes form per unit time
What happens to enzyme activity if the temperature is increased above the optimum?
Enzyme active site is denatured, meaning the active site loses its shape and can’t form enzyme substrate, complexes – decrease an enzyme activity
What can changes in pH do to the active site?
It can alter the active site causing enzymes to become denatured
Do all enzymes have a pH they work best at
Yes, enzymes have an optimum pH they work best at eg. Pepsin - acidic conditions, amylase – alkali conditions
What happens to the enzyme at either side of the optimum ph
They work less well because the incorrect pH changes the shape of the enzymes active site
How can enzyme concentration affect enzyme activity?
As more enzymes become available, there is more activity
The levels off as enzyme concentration increases because the number of substrate molecules become limiting
What are inhibitors?
A molecule that fits into the active site of the enzyme. It won’t get broken on, but prevent the enzyme substrate complexes forming.
What are the two main processes taking place in the digestive system?
Digestion and absorption
What are enzymes needed for in the digestive system?
To break down large insoluble food, molecules to small soluble ones that are absorbed into the bloodstream
