Required practicals paper 2

• How to measure a person’s reaction time


  -work in partners. partner 1 places his forearm of his dominant hand in the table,with his hand hanging of the edge

  -partner 2 should hold the ruler between the fingers of partner 1 at the 0 mark

  -partner 2 drops the ruler without warning and partner 1 has to catch it as quickly as possible

  -record the measuremlent on top of partner 1’s thumb

  -repeat 5 times with short rests in between

  -repeat the whole test but person 2 is in person 1’s position and person 1 is in person 2’s position
• Describe how to investigate the effects of light or gravity on the growth of newly germinated seedlings

  -incubate seeds in 3 Petri dishes and allow them to germinate

  -place one dish in full sunlight,one dish in partial and one in darkness

  -calculate mean height for each day for a week

  -plot a graph for mean seedling height (y) against day (x)
• The uses of gibberlins in agriculture/horticulture

  (growing plants for gardens)(3)


  -used to make seeds germinate quicker

  -encourage plants to flower

  -to make fruit grow larger
• uses of auxins (3)


  -used as weed killers in gardens

  -used as rooting powders

  -To promote growth in tissue culture
• how would you use sampling to estimate the population size of a plant species?

  -create a grid of the area using tape measures

  -use a random number generator to generate co-ordinates

  -set down quadrant on those co-ordinates and record the number of species in it

  -repeat step 2 and 3 many times

  -population size=area sampled/total area x total amount of species found in the quadrants
• describe how you would use continuous sampling to measure the effect of an abiotic factor in the distribution of plant species


  -lay tape measure along an area with ecological gradient

  -place quadrat at start and count number of plants

  -repeat at 5m intervals along the transect

  -record the value of abiotic factor at each sampling site

  -produce a graph of plant numbers (y) measurement of abiotic factor (x)
• describe how you would measure the effect of temperature on the decay of milk

  -place full-fat milk and cresol indicator in a test tube,and lipase solution in another test tube

  -place in a water bath and let the temp chance of both of test tubes plateu

  -transfer drops of lipase into the other test tube and start the stopwatch

  -stir until solution becomes yellow,then record the time taken

  -repeat steps above with different temperatures of milk

  -plot graph temp (x)and time taken (y)