Memory - Biology

• Explain how you could test food for the presence of starch.


  1) Add food to dimple tray.

  2) Add orange iodine solution

  3) Blue-black colour is a positive result for starch.

  
• Explain how you could test for sugars.


  1) Add food sample to test tube.

  2) Add 5cm3 of benedict reagent (Blue) into the test tube using a pipette.

  3) Heat the test tube using a water bath or using a bunsen burner. 70℃

  4) Brick red shows that sugars are present.

  
• Explain how you test for protein.


  1) Add food sample to test tube.

  2) Add 5cm3 of copper sulphate and 5cm3 of sodium hydroxide into the test tube using a pipette. This is called the biuret test.

  3) Gently shake the tube.

  4) Colour change from blue to lilac indicates a protein is present.

  
• Explain how to test for lipids.


  1)the test substance is mixed with 2cm3 of ethanol

  2)an equal volume of distilled water is added

  Shake

  3)a milky-white emulsion forms if the test substance contains lipids

  
• Amino acids


  The building blocks of proteins

  
• Protein


  A long chain of amino acids

  
• Protease


  An enzyme that breaks PROTEINS down into amino acids

  
• Lipase


  An enzyme that breaks FAT down into glycerol and fatty acids
• Carbohydrase


  An enzyme that breaks CARBOHYDRATES down into sugars

  
• Denatured


  The enzyme's SHAPE has been changed so it can no longer perform its function. It has been ...

  
• Active site


  The part of the enzyme where the substrate binds

  
• Substrate


  The substance that the enzyme works on (the reactant)

  
• Catalyst


  Any substance that speeds-up a reaction
• Baby food

  Often contains PROTEASE enzymes to 'predigest' proteins making it easier to digest
• Amylase


  An enzyme that breaks starch into sugars
• Bile


  A yellowish-green fluid made by the liver, which neutralises stomach acid and emulsifies fat
• Liver


  A large organ that makes bile
• Stomach


  An muscular organ which contains hydrochloric acid. Some protein is digested here by protease enzymes.
• Small intestine


  This is where most food is digested and absorbed
• Large intestine


  This is where water is absorbed from undigested food (producing faeces)
• Digestion


  Breaking large, insoluble molecules down to form small, soluble molecules
• Absorption


  Movement of small, soluble molecules across the lining of the small intestines and into the bloodstream
• Salivary glands

  (diagram)

  
• Stomach

  (diagram)

  
• Small intestines

  (diagram)

  
• Large intestines

  (diagram)

  
• Liver

  (diagram)

  
• Gall bladder

  (diagram)

  
• Pancreas

  (diagram)

  
• Emulsify


  Splitting large drops of fat into tiny fat droplets (increasing the surface area for enzymes)

  
• Enzyme


  A 'biological catalyst' which speeds-up chemical reactions.

  All enzymes are proteins. They have a specific shape!

  
• What is a Pathogen?


  a microorganism that causes infectious disease

  
• What do Pathogens include?

  bacteria and viruses and protists and fungi

  
• How do bacteria reproduce when they are inside the body?

  very rapidly

  
• What reproduces very rapidly when inside the body?

  bacteria

  
• What do bacteria release?


  harmful chemicals called toxins

  
• What do toxins do?


  damage tissues and make us feel ill

  
• Can Viruses reproduce by themselves?

  No

  
• Where do Viruses reproduce?

  inside a host cell

  
• What does the virus do first when it reaches a human cell?

  it invades the host's cells