Enzymes and Digestion Flashcards
Not all enzymes work inside cells. Give an example of where they don’t.
In the stomach because enzymes used in digestion are produced in the cells and then released into the stomach to be mixed with food
What do digestive enzymes do?
Break down large insoluble molecules into smaller soluble ones
Why do digestive enzymes break large molecules into smaller ones?
Because big molecules are too big to pass through the walls of the digestive system
Where are digestive enzymes made?
In glands
What are three examples of big molecules that are too big to pass through the walls of the digestive system?
Starch, proteins and fats
What are four examples of smaller molecules that can pass easily through the walls of the digestive system?
Sugars, amino acids, glycerol and fatty acids
What are the three digestive enzymes you need to know?
Amylase (a Carbohydrase), Protease and Lipase
Where is amylase made?
The salivary glands, pancreas and small intestine
What does amylase do?
Catalyses the digestion of starch into sugars
Where does amylase catalyse its things?
In the mouth and small intestine
Where is protease made?
In the stomach, the pancreas and the small intestine
What does protease do?
Catalyses the breakdown of proteins into amino acids
Where does protease catalyse its things?
In the stomach and small intestine
What is protease called in the stomach?
Pepsin
Where else does protease catalyse things apart from the stomach?
The small intestine
Where is lipase made?
In the pancreas and small intestine
What does lipase do?
Catalyses the breakdown of lipids (fats and oils) into fatty acids and glycerol
What kind of conditions do protease enzymes work best?
In acidic conditions like the stomach
What do glands in the stomach wall produce?
Hydrochloric acid to create the acidic conditions needed
What kind of conditions do amylase and lipase work best?
In alkaline conditions like the small intestine
What does the liver produce?
Bile
Where is bile stored?
The gall bladder
Is bile acidic or alkaline?
Alkaline
What is the purpose of bile?
Bile is squirted into the small intestine to neutralise the acid from the stomach to make the conditions slightly alkaline so lipase and amylase can work there
What does bile also do along with neutralising stomach acid?
It emulsifies fats
What does emulsifies mean?
Breaks down into tiny droplets
What is the point in bile emulsifying the fats in the small intestine?
It gives the lipase enzyme a larger surface area to work on which makes its digestion faster
What is the breakdown of food catalysed by?
Enzymes
Where are enzymes in the digestive system produced?
In glands and in the gut lining
What enzyme do the salivary glands produce?
Amylase
What does the liver produce?
Bile
What does the gall bladder store?
Bile
What happens in the large intestine?
Excess water is absorbed from food
What enzymes does the pancreas produce?
Protease, amylase and lipase
Where does the pancreas release its enzymes into?
The small intestine
What happens in the small intestine?
Digested food is absorbed out of the digestive system and into the blood
What enzymes does the small intestine produce? (hint - the same as the pancreas)
Protease, amylase and lipase
What does the stomach do with its muscular walls?
Pummels the food
What enzyme does the stomach produce?
Protease (pepsin)
What else does the stomach produce apart from the enzyme?
Hydrochloric acid
Why does the stomach produce hydrochloric acid? (2 reasons)
To kill bacteria, and to give the right pH for the protease enzyme to work, which is 2 - acidic
What happens in the rectum?
Faeces is stored
What is faeces mainly made up of?
indigestible food
