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Biology GCSE - Coggle Diagram

- - - - place into a beaker of acid
      - observe jelly slowly become colourless - acid diffuses in and neutralises NaOH
      - make agar jelly from sodium hydroxide and phenolphthalein - it will be pink
  - - - get a beaker of pure water, and a beaker of sugar solution/ brine
      - place the cucumbers in each one
      - obtain 2 cucumbers
      - after 24 hours, take out the cucumbers
      - the one in pure water should be the same, the one in brine should be floppy
    - - put the funnel into a beaker of pure water and leave the solution overnight
      - water will have been drawn up the tube
      - then pour some sugar solution down the glass tube
      - place some visking tubing over the end of a thistle funnel
  - - - a short distance means a faster rate of movement
      - this is why cell membranes are very thin
    - - the hotter the particles, the more kinetic energy they have, so they move faster
      - this means a higher rate of movement in the same time
    - - the larger the surface area to volume ratio, the faster the rate of movement
      - this is there is more exposed reactant per gram of reactant
    - - if concentration is higher on one side, the rate of movement will be faster for those particles
      - this doesn't apply to active transport, as it goes against the concentration gradient
- - - - add ~10 drops of Benedict's solution
      - leave the test tube for 5 mins
      - if positive, the solution will go from blue to green-yellow-red depending on concentration
      - prepare a water bath to 75°C
      - prepare a food sample and transfer 5ml to a test tube
    - - if positive, the solution will go from orange-brown to black or dark blue
      - add a few drops of iodine solution and gently stir
      - prepare a food sample and transfer 5ml to a test tube
  - - - prepare a sample of food and transfer 2ml to a test tube
      - add 2ml of biuret solution and mix by gently shaking
      - if positive, the solution will change from blue to pink or purple
  - - - prepare a food sample and add 5ml to a test tube
      - add 3 drops of Sudan III stain solution and gently shake
      - if positive, the solution will separate into 2 layers, the top one being red
  - - - all enzymes have an optimum pH (37° in humans)
      - after a certain point, the active site will begin to denature
      - a higher temperature means a higher rate of reaction
      - practical investigation
        
        use a pipette to add 15ml of hydrogen peroxide to a boiling tube
        
        place in a water bath at 10°C
        
        add a source of catalase e.g. 1cm³ of potato
        
        immediately put on the bung and attach to an upside down measuring cylinder in water
        
        you can collect the oxygen and measure how much is produced
        
        record oxygen produces, repeat 3 times and find an average
        
        the enzyme catalase breaks hydrogen peroxide into water and oxygen
        
        repeat with temperatures of 20, 30 and 40°C
    - - too high or too low, active site begins to denature
      - all enzymes have an optimum pH, similar to the environment they live in
      - practical investigation
        
        same as temperature investigation, but...
        
        instead of changing temperature, change the pH of a buffer solution
        
        as before, keep any control variables the same
    - - they are not changed or used up during a reaction
      - enzymes reduce the need for heat for increased reaction speed
      - they allow cells to focus only on speeding up metabolic reactions
- - - - a large organelle that contains cell sap to support the cell
    - - small organelles where proteins are made in the cell
    - - where photosynthesis takes place
    - - small organelles where most of the reactions for aerobic respiration take place
    - - a rigid structure made of cellulose in plants that surrounds the cell membrane
      - supports and strengthens the cell
    - - forms the outer surface of the cell and controls the substances that go in and out
    - - a gel-like substance where most of the cell's chemical reactions take place
      - contains enzymes to control the reactions
    - - contains the genetic material (DNA) that controls the cell's activities
  - - - membrane-bound organelles
      - multicellular and eukaryotic
    - - plants have chloroplasts, cells walls and vacuoles
      - plants store carbohydrates as starch or sucrose, animals as glycogen
- - - - activity level
        
        active people need more food
        
        because they are burning more glucose
      - age
        
        children and teenagers need more food
        
        because they are growing more and generally more active
      - pregnancy
        
        pregnant women need more food
        
        they need to provide energy for themselves and the parasite
    - - BURN THE BEAN
      - measure temperature change
      - energy in food = mass of water x temperature change x 4.2
      - energy per gram = energy in food / mass of food
    - - vitamins
        
        C
        
        citrus fruits
        
        prevents scurvy
        
        D
        
        eggs
        
        needed for calcium absorption
        
        A
        
        liver
        
        improve vision and keep skin and hair healthy
      - mineral ions
        
        calcium
        
        milk, cheese
        
        makes bones and teeth
        
        iron
        
        red meat
        
        needed for haemoglobin in blood
      - lipids
        
        provides energy, acts as energy store, insulation
        
        butter, oily fish
      - water
        
        food and drink
        
        almost every bodily function requires water
      - proteins
        
        meat, fish
        
        growth and repair, provides energy in emergencies
      - dietary fibre
        
        wholemeal bread, fruits
        
        aids movement of food, soft and manageable poos
      - carbohydrates
        
        pasta, rice, sugar
        
        provides energy