Biology foundation

• This is the GCSE combined science trilogy walkthrough for foundation tear and this is biology paper one that was sat by pupils in May 2019
• Student investigated the effect of light intensity on the rate of photosynthesis


  1. Used apparatus including stopwatch, pond weed, beaker, and observed gas bubbles produced

  2. Counted oxygen bubbles produced in a certain amount of time to measure rate of photosynthesis
• Light intensity


  Can be changed by adjusting the distance between the lamp and the pond weed
• Rate of photosynthesis


  Measured by counting oxygen bubbles produced in a certain amount of time
• Maximum rate of photosynthesis was around 34 arbitrary units
• Light intensity as a limiting factor

  At 200 light intensity, light was a limiting factor for rate of photosynthesis
• Other factors that can affect rate of photosynthesis

  • Carbon dioxide concentration
  • Amount of chlorophyll
  • Temperature
  • Amount of water available
• Oxygen entering a single-celled organism

  By diffusion due to the large surface area to volume ratio
• Calculating surface area to volume ratio of cube B


  1. Calculate surface area of one face

  2. Calculate total surface area

  3. Calculate volume

  4. Divide surface area by volume
• Part of blood that carries the most oxygen


  Red blood cells
• Gas that passes out of the blood in the alveolus

  Carbon dioxide
• Other ways the lungs are adapted for good gas exchange

  • Thin walls for short diffusion distance
  • Good blood supply for steep concentration gradient
• Biological structures in order from smallest to largest

  • Nucleus
  • Cell
  • Tissue
  • Organ
• One animal organ is the heart
• Root hair cell


  • Thin extension for large surface area to absorb water and minerals
  • Many mitochondria for active transport
• Reason to use low powered objective lens first

  Easier to focus and get a wider view of the sample
• Reason not to move objective lens towards the stage


  Lens and slide could collide and crack
• Calculating power of eyepiece lens

  Total magnification = eyepiece lens x objective lens

  Total magnification = 50, objective lens = 10

  Therefore eyepiece lens = 5
• Reason root hair cells do not contain chloroplasts


  They are in the soil where there is no light for photosynthesis
• Transpiration


  The process of water loss from leaves through stomata
• Cell X


  Guard cell
• Calculating real length of cell

  Real length = size of image / magnification

  Convert 25 mm to 25,000 micrometers

  Real length = 25,000 / 800 = 31.25 micrometers
• Reason for plastic bag around pot

  To trap water inside and ensure only water lost from leaves is measured
• Resolution of balance


  0.1 grams
• Calculating initial mass of plant

  Initial mass = Final mass + Mass of water lost
• Trap water


  Inside the plant and the pot to ensure water is only lost from the leaves
• Resolution of balance


  Smallest change a device can measure
• The resolution of the balance is 0.1 grams
• Calculating value x in table 1

  1. Finished mass 506.3

  2. Mass of water lost 4.9

  3. Add mass of water lost back to finished mass to get initial mass
• As temperature increases, the mass of water lost increases
• Factors that might affect rate of water loss from leaves

  • Light intensity
  • Wind or air movement
  • Rate of photosynthesis
• In 2000, the number of deaths from malaria was 840,000
• In 2015, the number of deaths from malaria was 440,000
• The greatest decrease in the number of deaths from malaria was between 2005 and 2010
• The conclusion that there were 800,000 deaths from malaria in 2002 is not correct because there was no actual data collected in 2002, it was just an estimate
• Malaria is caused by a protist and spread by mosquitoes (a vector)
• Vaccine against malaria


  Makes people immune so fewer people are infected
• Ways to control the spread of malaria

  • Sleep under nets
  • Use insecticides
  • Use insect repellents
  • Destroy mosquito habitats
• Pulmonary artery


  Carries deoxygenated blood away from the heart to the lungs
• The pacemaker cells that control the natural resting heart rate are found in the right atrium