Bio 2014 paper edexcel

• Sperm cells are involved in fertilisation. Define fertilisation.

  -sperm fuses with egg/penetrates egg

  -genetic information fuses/combines

  -haploid gametes /gametes have 23 chromosomes

  -diploid cells

  -23 pairs of chromosomes

  -zygote formed
• Describe the function of mitochondria.

  -aerobic respiration/using glucose/using oxygen

  -energy released for movement/ swimming /metabolism
• Gene mutations in DNA can produce abnormal mitochondria. Explain how a gene mutation can produce a different protein.


  -a change in a base/base sequence/order of bases/a change in mrna

  -addition/deletion

  -change in an amino acid / order of amino acids
• Structure X on the diagram contains DNA. Name structure X =Nucleus


  NUCLEUS=X

  
• DNA, the bases A and T are complementary.
• THIS PLANT CELL IS A LEAF PALISADE CELL


  LEAF PALISADE CELL

  
• Which piece of equipment would be used to measure the distribution of plants on the bark of the tree?a quadrat
• Some small plants can grow on the bark of trees
• The distribution of two plant species, species A and species B, growing on the north and south side of a tree was investigated
• The results are shown in the table
• Suggest reasons for the distribution of species B on the north and south sides of the tree

  1. Species B is able to grow on both (North and South) sides

  2. There are more on the south side because of a specific difference in a named abiotic factor eg lighter /darker on South side , temperature, pH, water level

  3. There are fewer on the north side because they are out competed by species A / idea of eaten more on North side
• Compare the heart rate of the fit person with the heart rate of the unfit person from 5 to 15 minutes.

  the unfit person’s heart rate is higher / faster(1)  idea that both react in the same way eg both peak at ten minutes, both increase when they start exercising (1)  heart rate increases more quickly (to maximum) (1)  heart rate decreases more slowly (back to resting rate) (1)  credit correct manipulated values obtained for heart rates (1)

  
• Cardiac output = stroke volume × heart rate.The stroke volume of the fit person at 10 minutes is 0.20 dm3 per beat. Calculate the cardiac output of the fit person at 10 minutes.Use the graph to help you.

  Correct substitution i.e. 0.20 x 110 (1) = 22
• Recovery period


  The time it takes for the heart rate to return to its rate at rest after exercise
• The fit person


  Has a shorter recovery period
• Fit person


  • Greater vital capacity
  • Greater blood flow
  • Greater stroke volume
  • Greater cardiac output
• Fit person


  • Less/no anaerobic respiration
  • Less/no lactic acid build up
  • Lactic acid removed faster
  • Lower oxygen debt
  • Less oxygen to replace
• The recovery period for the fit person was different from the recovery period for the unfit person