Digestion Flashcards
What is an enzyme?
A biological catalyst that speeds up reactions without it being used up itself
What is an active site?
A specially shaped area of an enzyme that matches the shape of the substrate it breaks down
What is induced fit?
The active site of an enzyme changes slightly as a substrate binds to it to create a tighter fit
What is the effect of temperature on enzyme reactions?
A higher temperature increases the rate of reaction until the heat changes the active site of an enzyme and denatures it
What is the effect of pH on enzymes
pH interferes with the bonds holding an enzyme together is it is too high or low
all enzymes have an optimum pH
How to investigate the effect of pH on enzyme activity?
- amylase catalyses the breakdown of starch
- place iodine solution into every well of a spotting tile
- heat water over a Bunsen burner
- add 1cm3 and 1cm3 of buffer solution to a boiling tube and place it in the water
- wait five mins
- add 5cm3 of starch solution to the boiling tube
- mix and start a timer
-every 30 seconds place a drop in each well of the spotting tile - when iodine remains brown orange not turns blue black then no starch is present
- Repeat with different buffer solution pH values
How to calculate rate of reaction?
Rate = 1000/time
What does carbohydrase do?
Break down carbohydrates into simple sugars
Where is amylase found?
salivary glands, pancreas, small intestine
What do proteases do?
Convert protein into amino acids
Where is protein found?
the stomach (where it is known as pepsin), the pancreas, and the small intestine
What do lipases do?
Convert lipids into glycerol and fatty acids
Where is lipase found?
the pancreas, the small intestine
What does bile do?
Neutralise stomach acid
Emulsify fats into droplets
How to conduct a food test?
- prepare food by breaking it down and adding to a beaker with distilled water
- transfer to a test tube and add test
