Digestive System Flashcards
What is a tissue?
A group of cells.
What are organs made of?
Tissues.
What does the pancreas contain?
- Hormones to control blood sugar.
- Some digestive enzymes.
How are the villi in the small intestine adapted?
- A large surface area to absorb soluble food molecules by diffusion and active transport.
- A thin wall for a short diffusion path.
- A good blood supply to carry food molecules away to maintain a concentration gradient.
What happens in the liver?
Bile is produced.
What happens in the small intestine?
- Absorption of food occurs through the villi.
- Enzymes are released.
What happens in the large intestine?
Water is absorbed, producing faeces.
What are carbohydrates made of?
Units of sugar.
Why are starch and cellulose complex carbohydrates?
They are made of long chains of simple sugar units.
What are lipids made of?
Three molecules of fatty acids linked to a molecule of glycerol.
What proteins made of?
Long chains of amino acids.
What are all chemical reactions in cells controlled by?
Proteins called enzymes.
What are enzymes?
Proteins.
What can enzymes do?
- Build large molecules from smaller ones, such as starch from glucose.
- Change one molecule into another.
- Break down large molecules into smaller ones.
What do digestive enzymes do?
Break down large molecules into smaller ones.
What is the effect of pH on enzyme action?
-pH affects the forces which hold the folded shape of the protein molecule in place. So, the shape of the active site changes - DENATURED.
How does an enzyme work best at optimum pH?
Its active site has the best shape so can work most efficiently.
Where are digestive enzymes produced?
By specialised cells in glands and in the lining of the small intestine.
Where do digestive enzymes work, unlike most enzymes?
Outside of the cells.
How does pH change throughout the digestive system?
- In the mouth and the small intestine, it is alkaline.
- In the stomach it is acidic.
Where is amylase produced and what does it do?
It is produced by the salivary glands, the pancreas and the small intestine. It catalyses the digestion of starch (breaks it down) into to glucose (sugars) in the mouth and small intestine.
Where is protease produced and what does it do?
It is produced by the stomach, pancreas and the small intestine. It catalyses the breakdown of proteins into amino acids in the stomach and small intestine.
Where is lipase produced and what does it do?
It is produced by the pancreas and the small intestine. It catalyses the breakdown of lipids into fatty acids and glycerol.
At what temperature does the human digestive system work best?
37*C (body temperature).
