B4

• What is the word equation for photosynthesis?

  Carbon Dioxide + Water = Glucose + Oxygen
• What is the symbol equation for photosynthesis?

  $6CO2 +$$6H2O =$$C6H12O6 +$$6O2$
• Where does photosynthesis take place?

  chloroplasts (contains chlorophyll which absorbs light)
• Is photosynthesis endothermic or exothermic?

  Endothermic (energy enters)
• What is glucose used for?

  • Respiration (transfers energy into glucose for plant to convert rest of glucose into useful substances)
  • Making cellulose (strong cell walls)
  • Making amino acids (glucose combined with nitrate ions = amino acids = proteins)
  • Stored as fats/oils (turned into lipids stored in seeds)
  • Stored as starch (turned into starch stored in roots, stem & leaves for photosynthesis in winter)
• What are the limiting factors effecting photosynthesis?

  • light (night)
  • temperature (winter)
  • chlorophyll (amount affected by disease & lack of nutrients = not enough chlorophyll made/ chloroplasts get damaged)
  • CO2 (if its warm/bright enough)
• What is aerobic respiration?

  respiration using oxygen ( most efficient & 24/7 process)

  Glucose + Oxygen = Carbon Dioxide = Water$C6H12O6 +$$6O2 =$$6CO2 +$$6H2O$
• What is Anaerobic respiration?

  Respiration without enough oxygen (anaerobic as well as aerobic, aerobic isn't fully oxidised)

  Glucose = Lactic acid
• What are the products of anaerobic respiration in plants and yeast?

  Glucose = Ethanol + Carbon Dioxide
• What is a green house?

  the most ideal environment for plants to grow - helps to trap suns heat
• How does a greenhouse work in different conditions?

  • Winter (heater to keep temperature ideal)
  • Summer (shades & ventilation if it gets too hot)
  • Night (artificial light once sun goes down)
  • CO2 (paraffin heater as it burns CO2 is produced)
• What are the advantages of greenhouses?

  • Plants are protected from pests & disease
  • Can add fertilisers to soil providing minerals
  • Can control conditions (eg levels of CO2)
• What is the disadvantage of greenhouses?

  Expensive (however growing in right conditions = decent crop)
• What is respiration?

  The process of transferring energy from glucose which goes into every cell
• Is respiration endothermic or exothermic?

  Exothermic (transfers energy to environment)
• What is respiration used for?

  • Build larger molecules from smaller ones
  • allows muscles to contract (animals)
  • energy produces keeps body temperature steady in colder surroundings (mammals)
• What is the word equation for respiration?

  Glucose + Oxygen = Carbon Dioxide + Water
• What is the symbol equation for respiration?

  $C6H12O6 +$$6O2 =$$6CO2 +$$6H2O$
• What is metabolism?

  The sum of all the chemical reactions that happen in a cell or the body
• Examples of large molecules made from smaller ones:

  • glucose joins to make starch (storage in plants), glycogen (storage in animal cells) & cellulose (component of plant cell wall)
  • lipid made from glycerol + fatty acids
  • glucose combined with nitrate ions = amino acids
• Examples of larger molecules broken into smaller ones:

  • Glucose broken down in respiration
  • Excess protein broken down to produce urea
• Exercise

  1. muscles contract more = more energy = increased respiration
  2. Breathing rate & breath volume increase to get more oxygen into blood
  3. Heart rate increases to get oxygenated blood around body faster & removes CO2 quicker
• Vigorous exercise

  body cant supply oxygen to muscles fast enough so respirates anaerobically (lactic acid builds up = painful)
• Why do we breath so hard after exercising?

  need to get oxygen into blood to be transported to muscle cells because couldn't keep up with demand
• How does the body deal with high levels of lactic acid?

  body transports lactic acid to liver where its converted back to glucose
• Investigating effects of exercise on body:

  1. test breathing rate by counting breaths + test heart rate by taking pulse
  2. Plot into bar chart
  3. Repeat on yourself and calculate mean
  4. Experiment on numerous people
• Photosynthesis Practical:

  1. Take a boiling tube & place it 10cm away from LED light source
  2. Fill boiling tube with sodium hydrogen carbonate solution
  3. Put a piece of pondweed into the boiling tube with the cut end at the top
  4. Leave for 5 mins to acclimatise to conditions in boiling tube
  5. Start a stop watch & measure volume of oxygen produced in 1 min (using gas syringe)
  6. Repeat two or more times to calculate mean
  7. Repeat whole experiment increasing distance of boiling tube by 10cm each time
• Photosynthesis practical independent variables:

  • temperature
  • Distance of light from pondweed
  • Species of pondweed
• Photosynthesis practical control variable:

  • Volume of gas produced