b2 - organisation

• principles of organisation


  cell - the basic building blocks of all living organisms.

  tissue - group of cells with a similar structure and function

  organs - collections of tissues performing specific functions

  organ systems - organs that work together to form organisms
• RP - food tests 


  preparing a sample: break up the food using a pestle and mortar. add water and stir. filter the mixture, collect the solution and test it
• testing for starch


  reagent: iodine

  negative result: stays brown

  postie result: turns black

  risk: irritant (wear goggles)
• testing for simple sugar

  reagent: benedict's solution (and heat)

  negative result: stays blue

  positive result: turns green -> yellow -> brick red (depending on amount of sugar)

  risk: burns from bunsen burner
• testing for protein


  reagent: biuret solution (sodium hydroxide and copper sulfate)

  negative result: stays blue

  positive result: turns purple

  risk: sodium hydroxide is corrosive. copper sulfate is an irritant. (wear goggles)
• enzyme overview


  enzyme break down large insoluble molecules (the substrate) into the smaller soluble molecules (products) which can be absorbed into the blood stream.
• lock and key theory


  the active site of the enzyme has a specific shape which will only fit into one type of substrate
• amylase

  made in: small intestine, pancreas, salivary glands

  breaks down carbohydrates (starch) into simple sugars for respiration and building carbohydrates
• protease


  made in small intestine, pancreas and stomach

  breaks down protein into amino acids for building proteins
• lipases

  made in small intestine and pancreas

  breaks down lipids into fatty acids and glycerol for building lipids
• bile


  made in the liver and stored in gall bladder

  it is alkaline to neutralise hydrochloric acid from stomach

  emulsifies fats to form small droplets - increases surface area

  the alkaline conditions and large surface area increase the rate of fat breakdown by lipase
• enzyme activity


  if enzyme placed into the incorrect temperature of pH, the active site changes shape and the enzymes is denatured - it will not work anymore.

  rate of activity is highest at the optimal temperature and pH
• plasma


  carries other blood cells, glucose, CO2 around the body
• platelets


  help blood to clot
• white blood cells


  make antibodies and antitoxins to destroy pathogens