B2-Organisation

Created by

Isaac Lewis

Cards (100)

What is a reactant/substrate?
A substance that takes part in a reaction
What is an enzyme?
A biological catalyst
What part of an enzyme binds to substrates?
The active site
The lock and key theory is?
That enzymes active site and substrate fit perfectly together. They are complementary
Why do an enzyme only catalyse one reaction?
The active site of an enzyme has a complementary shape to a specific substrate.
What does it mean when an enzyme has been denatured?
The shape of the active site changes so that it can no longer fit the substrate.
What can cause an enzyme to denature?
Extremes of pH or temperature
Why are enzymes described as biological catalysts?
Speed up a reaction, lower activation energy, not used up in the reaction
What does complementary mean?
That two shapes fit perfectly together
Where in the body is amylase produced?
In the salivary glands and the pancreas
What does amylase break down?
Starch is broken into maltose
Where are proteases produced in the body?
The stomach and the pancreas
How do proteases work?
They break down proteins into amino acids
Where are lipases produced?
In the small intestine and the pancreas
How do lipases work?
They break down lipids (fats) into glycerol and fatty acids
Where are nutrients absorbed into the blood?
In the small intestine
What happens at the mouth?
Enzymes chemically digest starch and some fats while the teeth and tongue physically digest food by crushing it.
What is chemical digestion?
The chemicals in food being broken down by enzymes
What is physical digestion?
The body crushing and churning food to break it into small chunks
Why is the stomach acidic?
To provide an optimum environment for the enzymes and to kill pathogens.
What pH is the stomach approximately?
pH 2 - Contains Hydrochloric acid
What is chemically digested in the small intestine?
Proteins, lipids and carbohydrates
What organ produces lots of enzymes and releases them in pancreatic juices?
The pancreas
Where are pancreatic juices released into?
The small intestine
Where is bile made?
The liver
Where is bile stored and released from?
The gall bladder
Where is bile released into?
The small intestine
What two function does bile have?
Neutralise stomach acid entering the small intestine and emulsify lipids
What benefit does emulsifying lipids have in the small intestine?
It allows lipase enzymes to reach them and increases their surface area
What pH is in the small intestine
Slightly alkaline
What is continuous sampling?
Regularly taking samples of a reaction to test
How do you test for the presence of starch?
Add iodine, if it changes from orange to a blue/black colour then starch is present
How do you test for the presence of proteins?
Add biuret reagent and look for a purple colour change
How do you test for the presence of reducing sugars?
Add benedict's reagent to sample, heat and look for a colour change from blue to orange/red
How do you test for fats?
Use sudan III solution to sample, gently shake. Sudan stains lipids. The mixture separates into two layers. The top layer will be red.
How can you control temperature in a reaction?
Using a water bath or an electric heater
What is an independent variable?
A variable that we change in a reaction
What is a dependent variable in a reaction?
A variable that we measure in a reaction
What is a control variable in a reaction?
A variable that we keep the same in a reaction
Why do you have control variables?
To make your results valid. So any change in the dependent variable is due to the change you made in the independent variable.