Digestive System Part 3 - Enzymes Flashcards
What is an enzyme?
An enzyme is a chemical that helps break down food into smaller pieces that are easier to deal with.
STAGE 1 - EATING
We use our ______ to grind down the food, making it easier to ______. This is a _____ change – although our food does not look the same as when
we ate it, it is still what we put in. Our mouths also contain _____ , which has a substance in it which begins to chemically break food down. This is called an _____.
teeth swallow physical saliva enzyme
STAGE 2 - OESOPHAGUS
When we swallow, the food moves down the long tube from the ____ to the _____. This is NOT a chemical or a physical change.
mouth
stomach
STAGE 3 - STOMACH
The stomach is the “washing machine” of the digestive system, where food is mixed with _______ juices.
Digestive juices are a mix of ____ and enzymes – both of which help to break down food. In the stomach, a ______ change occurs.
digestive
acids
chemical
STAGE 4 - SMALL INTESTINE
In the small intestine, more _____ is added, and there is some more _____. More “washing machine” style action – but things aren’t necessarily staying where
they are. Food that is ______ _____ as much as it can be then goes to the _____ to be used for
energy. _______ and _______ change.
liquid mixing broken down blood chemical physical
STAGE 5 - LARGE INTESTINE
All food which has not been ____ ____ up to this point reaches the large intestine. Any _____ which is left in the food passes back to the body, leaving “solid” material. _______ and ________ change.
broken down
water
chemical
physical
STAGE 6 - WHAT HAPPENS TO THE SOLID WASTE?
Solid waste left moving in the large intestine is ________ through the _____ in the form of ____ (POO). PHYSICAL CHANGE
excreted
anus
faeces
How is starch digested?
Starch molecules are too big to be absorbed, so they are broken down into maltose by amylase enzymes. These maltose molecules are still too big in order to be absorbed, so they are further broken down into glucose units, which can be readily absorbed into the bloodstream.
What is glucose needed for in the body?
Energy.
How are proteins digested?
Proteins are long chains of amino acids that are too big too be absorbed, so the large chains are broken down by protease from the pancreas into peptides. Theses peptides are still too big to be absorbed, so the protease from the small intestine break the peptides into singular amino acids, which can be readily absorbed into the bloodstream.
How are fats absorbed?
Fats are molecules made up of fatty acids and glycerol. These molecules are too big to be absorbed, so bile from the liver mixes with the fat to create an emulsion, and the lipase enzymes from the pancreas break them down into fatty acids and glycerol, which are readily absorbed into the bloodstream.
What are enzymes made of?
They are protein molecules, therefore they are made up of amino acid chains that are specifically ‘folded’ to create unique 3D structures.
What happens at an enzymes active site?
The same way that a key fits into a lock, a substrate fits into an enzyme’s active site. The enzyme is the lock, and the reactant is the key.
How does a chemical change between the reactant and the enzyme happen?
When a compatible reactant fits into an enzyme, they fuse together to create a enzyme reactant complex, and then the process happens which produces new products from the reactant. The enzyme remains the same. Another process that can happen is when two compatible products fuse with an enzyme to create a larger product.
When is bile released into the small intestine?
When the acidity from the stomach is too high for try enzymes in the small intestine to further break down food.
