b3

• what is a tissue?

  a group of cells with similar structure and function
• what are organs?


  collections of tissues performing at specific functions
• what is a organ system?

  a gorup of organs that perform specific functions in the body
• what are carbohydrates made up of?

  units of sugar
• what is the observation and test for starch?

  iodine

  yellow/red to blue/black if starch is present
• what is the observation and test for protein?

  biuret test

  blue to purple if protein is present
• what is the observation and test for lipids?

  ethanol

  a cloudy white layer if a lipid is present
• what is safety precaution is food test?

  biuret solution is corrosive

  water chemical and eye protection
• what do complex carbohydrates contain?


  long chains of simple sugar unites bonded together
• what do lipids consist of?

  three molecules of fatty acids bonded to a molecule of glycerol
• what are protein consist of?

  long chain of amino acids
• what does catalysts do?

  increase the rate of chemical reaction without changing chemically themselves
• what are enzymes?


  biological catalysts and catalyse specific reactions in living organsims due to the shape of their active site
• what is the active site

  amino acid chains which are folded to form the active site
• what is metabolism?


  sum of all the reactions in a cell or the body
• what is enzyme activity affected?

  temperature and pH
• what happens to high temperature with enzyme?

  denature
• what can affect the shape of the active site?

  pH
• what does digestion involve?

  the breakdown of large insoluble molecules into a soluble substances that can be absorbed into the blood across the wall of the small intestine
• how are digestive enzymes produced?

  by specialised cells
• what does carbohydrase do?

  breakdown carbohydrates in simple sugars
• what does proteases do?

  catalyse the breakdown of proteins to amino acids
• what does lipsaes do?

  catalyse the breakdown of lipids to fatty acids and glycerol?
• making digestion efficient


  protease enzymes of the stomach works best in acid conditions

  stomach produces hydrochloric acid,which maintains a low pH

  enzymes made in the pancreas and the small intestine work best in alkaline conditions

  bile producedn by the liver,sotred in the gall bladder,releases through bile duct neutralises acid and emulsifes fats