Organisation - enzymes Flashcards
What are enzymes?
Large proteins that catalyse reactions.
How do you work out the rate of reaction?
change in mass/ change in time
What is the active site?
Where the reaction takes place.
What is the lock and key theory?
The active site is like a lock and the substrate is a key and the active site will only catalyse a specific reaction because the substrate fits into its active site.
What affects the rate of enzyme action?
pH and temperature.
How does pH affect the rate of enzyme action?
1 If the pH is extreme then the active site changes.
2 Then the substrate can no longer bind to the enzyme.
3 So the enzyme cannot catalyse the reaction - the enzyme is denatured.
How does temperature affect the rate of enzyme action?
1 Increasing temp, increases the reacting activity,
2 Once the enzymes optimum temp is reached the reactivity decreases.
3 The active site changes and the enzyme is denatured and stops working.
What are the 3 main digestive enzymes?
Amylase, proteases and lipases.
What do digestive enzymes do?
Convert food into small, soluble molecules that can be absorbed into the bloodstream.
What do carbohydrases break down carbohydrates into?
Simple sugars.
Where is amylase produced?
In the salivary glands, pancreas and small intestine.
What is the catalysed reaction involving amylase?
Starch to maltose (simple sugar)
Where are proteases produced?
In the stomach, pancreas and small intestine.
What is the catalysed reaction involving proteases?
Proteins into amino acids.
Where is lipase produced?
In the pancreas and small intestine.
What is the catalysed reaction involving lipase?
Lipids to fatty acids and glycerol.
What is bile?
Bile is an alkaline substance that is stored in the gall bladder after having been produced in the liver.
What is emulsification?
Process of bile breaking up fats into tiny droplets.
What does bile also do?
Neutralises acid from the stomach to stop enzymes from becoming denatured.
How do you test for sugars?
1 Add benedict solution to sample and heat for 2 mins.
2 Turns green/yellow/red/brown if sugar is present.
How do you test for proteins?
1 Add biuret solution.
2 Turns mauve/purple.
How do you test for starch?
1 Add iodine solution.
2 Solution turns blue/black if starch is present.
