Cell Organisation U2

• What is a tissue ?

  • A group of similar cells that perform a specific function
• What is an Organ ?


  • A group of different tissues that work together to perform a certain function
• What is an Organ System ?

  • A group of organs that work together to perform a specific function
• How do Enzymes work ?

  • They have an active site that is specific to a substrate so they bind to it
• What are the 3 main enzymes ? What do they break their substrates down into ?


  • Amylase - Starch -> Glucose

  • Protease - Proteins -> Amino acids

  • Lipase - Fats -> Fatty acids + Glycerol
• Where are all Enzymes produced ?


  • Pancreas
• What does Bile do ?


  • Bile neutralises the stomach acid in the food

  • Bile helps with emulsification by breaking down large fat molecules into smaller molecules
• Where is Bile stored ?


  • Gallbladder
• What are the 4 food tests ?


  • Sugar - Benedict’s test

  Blue -> Green / Yellow / Brick red

  • Starch - Iodine Solution

  Orange / Brown -> Black / Blue

  • Proteins - Biuret Test

  Blue -> Pink / Purple

  • Fats - Sudan III test

  Bright red layer at the top
• What are the 3 Blood Vessels ?

  • Arteries - Carries blood away from the heart

  • Capillaries - Involved in exchange of materials

  • Veins - Carries blood to the heart
• How is each Blood Vessel adapted ?


  • Arteries - Thick muscular walls that are elastic to withstand high pressure. • Veins - They have a large lumen to help blood flow and valves to prevent backflow of blood.

  • Capillaries - They have a very small lumen and thin walls for gas exchange.
• What is Cancer ?


  • Uncontrolled growth of mutated cells
• How is a leaf structured ?

  • Waxy cuticle - Protects the inside of the plant by a border

  • Palisade mesophyll - The part were the most photosynthesis happens

  • Spongy mesophyll - Air spaces that allow gases to diffuse in and out

  • Xylem / Phloem - Transported water / mineral ions / food

  • Meristem - Growing tips of shoots and roots that are able to differentiate
• What is Transpiration and Translocation ?

  • Transpiration - Water being evaporated through the leaf

  • Translocation - Transportation of sugars and nutrients through the phloem