B3 Organisation and the digestive system

The process of breaking down large insoluble molecules in your food into small soluble molecules

To digest food and temporarily store it Produces digestive acids

To help further digest food coming from the stomach

Turns food waste into stool

Removes waste and extra fluid from your body

Processes blood and breaks down, balances and creates nutrients Bile is produced

Stores bile

A biological catalyst that speeds up chemical reactions in living organisms They are large protiens

They have an active side with a specific shape and a specific molecule fits into the active side where the chemical reaction takes place The shape is very important and only one sort of enzyme will work on each substrate

The part of the enzyme where the reaction takes place They have a specific shape so that a specific substrate fits into it (Lock and key)

The molecule that fits into an enzymes active site and reacts to form a product or products

Used in cellular respiration to provide energy Made from simple sugars

An energy store, used to make hormones Fatty acids and glycerol

Growth repair and maintenance Amino acids

Benedict’s test Add solution and benedict’s solution to a test tube Heat it If sugars are present there will be a colour change from blue to brick red

Iodine Add a few drops of iodine to sample If starch is present there will be a colour change from orange to blue/black

Emulsion test (Ethanol) Dissolve some of the test sample in ethanol Pour this into a test tube of water If lipids are present here will be a cloudy white emulsion

Biuret Test Add biuret solution to test sample If proteins are present the will be a colour change from blue to lilac

Adjusts pH to optimum for protease

Speeds up the digestion of protein

Protects the stomach from auto digestion

Liver Gall bladder Small intestine

It is alkaline to neutralise stomach acid and make partly digested food pH 8 - the optimum pH for enzymes in the small intestine It also emulsifies fats, meaning it breaks them down into smaller droplets (increased surface area) to increase their rate of digestion

Carbohydrase (amylase) Protease Lipase