B3 Flashcards
What is a tissue?
A group of cells with similar structure and function
What are organs?
Collections of tissues performing specific functions
How are organs organised?
Into organ systems which work together to from organisms
What are organ systems?
Groups of organs that perform specific functions in the body
What is the digestive system in a mammal?
An organ system where several organs work together to digest and absorb food
What are carbohydrates made up of?
Units if sugar
What are simple sugars?
Carbohydrates that contain only one or 2 sugar units
What do complex carbohydrates contain?
Long chains of simple sugar units bonded together
What do lipids consist of?
3 molecules of fatty acids bonded to a molecule of of glycerol
What are protiens made up of?
Long chains of amino acids
What is the test for starch?
Iodine
What is the test for sugar?
Benedict’s
What is the test for protien?
Biuret
What must be used during food tests?
Safety goggles
What are the steps to prepare for food tests?
- Take food sample and grind with distilled water using a mortar and pestle to make a paste
- Transfer paste to a beaker and add more distilled water, stir so the chemicals in the food dissolve in the water
- Filter the solution to remove suspended food particles.
- Then test for each food
What are the steps when testing for starch?
- Place 2mc cubes of food solution into a test tube
- Add a few drops of iodine solution that is orange
- If starch is present the iodine will turn blue-black, if their is no starch the iodine will stay orange
What are the steps when testing for sugar?
- Place 2cm cubes of food solution into a test tube
- Add 10 drops of denedict’s solution which is blue
- Place test tube into a water bath or beaker with boiled water and leave for 5 minuites
- If sugars are present the Benedict’s solution will change colour, if green then their is a small amount of sugar, if yellow then their is more sugar present but if brick red then their is a lot of sugar present