topic b2- organisation

• organisation of cells

  • cells
  • tissues
  • organs (stomach and intestines)
  • organ systems (digestive system- lots of enzymes in it)
• lock and key

  each substrate (key) fits one specific active site (lock)

  
• enzymes are

  biological catalysts
• catalyst

  substance that speeds up the rate of reaction without being used up
• lock and key theory

  the idea that an enzyme's active site fits only one type of substrate
• enzymes need the right conditions- they work at on

  • optimum pH
  • optimum temperature
  • of these conditions aren't met they will denature
• denature

  the active site will become misshapen for the substrate
• optimum temperature

  
• optimum pH

  
• optimum value depending on the enzyme

  as you can see with the various crosses and lines here
• for the optimum graphs

  x- optimum pH/ temp
• enzymes- in the body

  • carbohydrase
  • protease
  • lipase
• carbohydrase

  • breaks down carbohydrates
  • into simple sugars
• protease

  • breaks down proteins
  • into amino acids
• lipase

  • breaks down lipids/ fats
  • into glycerol + 3 fatty acids
• digestive system

  • mouth
  • oesophagus
  • stomach
  • small intestine
  • large intestine
  • rectum - > waste food is stored
• the digestive system

  how does food you eat travel through your body
• mouth- key organ functions

  release saliva which contains amylase to begin breakdown
• stomach- key organ functions

  • pummels food
  • creates protease
  • and contains stomach acid to kill bacteria
• small intestine- key organ functions

  food absorption
• large intestine- key organ functions

  water absorption
• pancreas- key organ functions

  produces all three enzymes
• liver- key organ functions

  produces bile which neutralises stomach acid
• gall bladder- key organ functions

  stores bile
• rectum- key organ functions

  where indigestible food in the form of faeces is stored
• starch

  iodine
• sugars

  benedicts
• proteins

  biuret
• lipids

  sudan stain
• test for starch

  • add a few drops of iodine to food sample
  • gently shake to mix
  • if starch is present, colour sample from orange to blue/ black
• test for sugars

  • add a drop of benedicts solution to a prepared food sample
  • gently heat
  • if positive, you will see a colour change from blue to brick-red
• test for proteins

  • add a few drops of biuret solution to a food sample
  • gently shake to mix
  • if positive, colour change from blue to purple/ lilac
• test for lipids

  • add a few drops of sudan stain solution to food sample
  • shake the tube to mix
  • if lipids are present, a distinct layer will form as the lipids separate
• starch

  orange to blue/ black
• sugars

  blue to brick-red
• proteins 


  purple/ lilac
• lipids

  a distinct layer
• circulatory system

  • heart
  • blood
• the lungs

  
• the pathway through the lungs

  • mouth/ nose
  • trachea
  • bronchus
  • bronchioles
  • alveoli