Seneca Flashcards
(28 cards)
Why is bile important?
(Fats)
-Bile breaks up fats into tiny droplets, through a process called emulsification.
-The tiny droplets have a higher surface area than the original fat drop.
-This increases the rate of the lipase-catalysed reactions that break fats down.
What does bile do for enzymes?
-Enzymes in the small intestine operate best in alkaline conditions.
-Bile neutralises acid from the stomach to stop these enzymes becoming denatured (lose their activity).
How does bile help with digestion?
Bile breaks up fats (like oil) into tiny droplets, through a process called emulsification. The tiny droplets have a higher surface area than the original fat drop, which increases the rate of the reactions (catalysed by lipase) that break fats down.
What is Amylase?
Carbohydrase enzymes break carbohydrates down into sugars. Amylase is a type of carbohydrase that can break down starch in our bodies:
What does Amylase do?
Amylase breaks down starch into its constituent simple sugars (predominantly maltose).
What is starch made of?
Starch → Maltose (+ other sugars).
The sites of action of amylase are:
The small intestine.
The mouth.
Amylase is produced in:
Pancreas.
Salivary glands.
What are proteases?
Proteases are digestive enzymes that can break down proteins into amino acids.
The sites of action of proteases are the:
Small intestine.
Stomach.
Proteases are produced in the:
Pancreas.
Stomach.
What do proteases break proteins into?
Protein → Amino acids.
What is lipase?
Lipase is a type of digestive enzyme that breaks down lipids into glycerol and fatty acids.
What does lipase break lipids into?
Lipid → glycerol + fatty acids
Lipase is produced in the:
Small intestine.
Pancreas.
What helps us to test what food substance is present?
Reagents
How do you test for food substances?
The first step is to grind up the food and add distilled water to dissolve some of the food. You can then test for the food substances:
Describe starch food test
Add iodine solution to test for starch.
It will turn blue-black if starch is present.
Describe lipids food test
To test for lipids, add Sudan III (a fat-soluble dye).
If lipids are present, a red-stained oil layer will float on the water surface.
The presence of lipids can also be tested by adding ethanol.
The solution is added to water and shaken. If the solution turns cloudy, lipids are present.
What are the two different chemicals for lipids?
- Sudan III
- Ethanol
How do you test for proteins?
Add Biuret solution to test for proteins.
It will turn mauve or purple if proteins are present.
How do you test for sugar?
Add Benedict’s reagent and heat for about two minutes to test for sugar.
It will turn any of green, yellow or red if sugar is present.
The colour depends on the concentration.
When investigating the rate of enzyme activity, what factors need to be kept constant?
pH: Every enzyme has an optimum pH. Extremes of pH will cause the enzyme to denature. pH can be kept constant by using a buffer.
Temperature: Increasing the temperature will initially increase the rate of enzyme activity as the enzymes will have more kinetic energy. Above a certain temperature, enzymes denature as the high temperature breaks the bonds holding together the enzyme.
Enzyme concentration: Increasing the enzyme concentration increases the number of active sites available, which causes the rate of reaction to increase.
Substrate concentration: Increasing the substrate concentration increases the rate of enzyme activity, as there are more substrate molecules to bind to the enzyme active site.
What will happen to the rate of enzyme activity if the substrate concentration is continually increased?
Rate will increase and then plateau
