candidate entry is about two thirds for ISA and one third for EMPA
there is an approximate equal split between which of the two ISAs is submitted
the ability range is similar for both routes
the outcome of the two routes is similar
Year (entry) A* A B C D E U 2009 AQA AS Biology (26361) 17.2 34.0 52.2 68.2 81.1 100.0 National AS Biology 18.6 35.5 53.3 69.3 82.6 100.0 2010 AQA AS Biology (32672) 18.9 36.4 54.7 71.0 83.9 100.0 National AS Biology (83408) 18.7 36.4 54.3 70.3 83.6 100.0 AQA A level Biology (23295) 8.8 29.4 52.5 73.1 88.2 97.2 100.0 National A Level Biology (55485) 8.0 28.5 51.7 72.4 87.6 96.8 100.0
A* A B C D E U A level Human 2009 13.1 34.4 57.0 77.3 92.9 100 2010 3.0 11.8 31.2 54.6 77.5 93.4 100 A level Biology 2010 8.8 29.4 52.5 72.1 88.2 97.2 100 National A level 2010 8.0 28.5 51.7 72.4 87.6 96.8 100 AS Human 2009 7.5 18.3 35.6 53.9 69.1 100 2010 8.8 21.0 40.7 57.0 73.1 100
calculate the rate of change from a graph showing a linear relationship
draw and use the slope of a tangent to a curve as a measure of rate of change
calculate circumference and areas of circles, surface areas and volumes of rectangular blocks and cylinders when provided with appropriate formulae
To help you process your data, the time required for each stage of the cell cycle can be calculated using the formula: Number of minutes = number of cells in stage x 720 to complete a stage total number of cells counted Stage Number of cells Time in each stage Interphase 177 504 Prophase 4 7.2 Metaphase 7 14.4 Anaphase 1 2880 Telophase 63 180
Stage of mitosis Number of cells in stage of mitosis Percentage of cells in stage of mitosis Time to complete stage of mitosis / minutes Prophase 108 0.74 72.9 Metaphase 16 5 21.6 Anaphase 8 10 13.5 Telophase 28 2.86 3.85
A scientist studying onion root tips found that the time taken for mitosis was about 80 minutes . She recognised that the proportion of 80 minutes that a stage of mitosis took to complete could be found from the percentage of cells in that stage of mitosis. She used this to calculate the time in minutes for each stage of mitosis. Use the scientist’s method to complete the table. Stage of mitosis Number of cells in stage of mitosis Percentage of cells in stage of mitosis Time to complete stage of mitosis / minutes Prophase 108 112.5 54 Metaphase 16 10 8 Anaphase 8 5 4 Telophase 28 17.5 14
produces data of time taken for pH indicator to turn blue following exposure of respiring bacteria to different temperatures
Table 1 Temperature ( o C) Test 1 Test 2 Test 3 Average (m) Colour Time (m) Colour Time (m) Colour Time (m) 20 Blue 3.20 Blue 1.55 Blue 2.50 2.41 30 Blue 2.53 Blue 3.06 Blue 4.09 3.22 40 Blue 1.26 Blue 2.35 Blue 2.20 1.93 50 Blue 1.46 Blue 1.02 Blue 0.45 0.97 60 Blue 0.60 Blue 1.25 Blue 2.26 1.37
Table 2 ‘ Effect of temperature on time taken to change colour’ Time (s) Average (s) Temp o C Tube 1 Tube 2 Tube 3 20 193 159 171 174 30 128 131 176 145 40 91 82 117 97 50 97 103 120 107 60 260 317 302 293
Table 3 Test tube Temperature of water bath Time taken to turn blue Repeat time taken to turn blue Average 1 20 o C 7 minutes 15 seconds 7 minutes 11 seconds 7 minutes 13 seconds 2 30 o C 2 minutes 1 minute 45 seconds 1 minute 52.5 seconds 3 40 o C 36 seconds 47 seconds 41.5 seconds 4 50 o C 34 seconds 31 seconds 32.5 seconds 5 60 o C 8 minutes 57 seconds 9 minutes 33 seconds 9 minutes 15 seconds
Context - table shows data for fresh mass and dry masses of cucumbers before and after adding either water or liquid fertiliser to them.
Question – What conclusions can be drawn about the effects of using liquid fertiliser on the mass of cucumbers? (2 marks)
Comment – ‘effects’ and ‘mass’ are general so answer can be specific about direction of effect (increase or decrease) on type of mass (fresh or dry). Furthermore, there is the opportunity to compare extent of changes e.g. “fresh mass increased greatly but there was only a small decrease in dry mass.”
“ Explain the change in the mean number of metaphases over the first six hours”
Answer: “Over the first 6 hours numbers increase. The biggest increase was during the 4 to 6 th hour. From 0 to 6 hours the mean number has increased by 30, that means it has doubled during the 6 hours.”
The table shows the respiratory minute volume (volume of air inspired per minute) of three healthy young men subjected individually to a progressive decrease in the oxygen content of their inspired air. Carbon dioxide content was held at a constant level. The RMV was calculated for each minute for 10 minutes as shown. Time / minutes 1 2 3 4 5 6 7 8 9 10 Oxygen content of inspired air / % 21 18 16 14 12 10 8 6 5 4 RMV / dm 3 per minute Man A 6.6 6.8 6.9 6.9 7.2 8.6 12.9 18.2 21.0 25.5 Man B 7.4 7.4 7.3 7.3 7.3 7.4 11.5 18.0 19.7 24.4 Man C 7.0 6.8 6.8 6.8 7.1 8.0 11.6 17.8 19.3 25.1
A student made up a 1% solution of amylase using water and a 10% solution of amylase. Draw a table to show the volume of water and the volume of 10% solution of amylase that a student would need to make 10 cm 3 of a 1% solution of amylase.
Draw a table to show how you produced the 5 different concentrations of reducing sugar solution.
You incubated one of your starch solutions with 2% amylase solution and the other starch solution with 1% amylase solution. There is more reducing sugar in the mixture incubated with 2% amylase than the mixture incubated with 1% amylase. Suggest how you could use Benedict’s solution to compare the amount of reducing sugar in the two mixtures.
Describe a method to compare the amount of reducing sugar that might be found in the liquid surrounding a visking tubing bag.
A student wanted to improve her investigation of the effect of temperature on milk digestion by trypsin, by using control experiments. She set up a test tube containing milk and buffer at each temperature. She did not add trypsin to these tubes. What would these control experiments show?
Doctors investigated the effect of drinking caffeinated tea on heart rate. What treatment should those in the control group receive? Explain your answer.
It is not essential to have the same number of people in the experimental and control groups in an investigation like this. Explain why it is not essential.
Doctors investigated the effect of different types of ORS in the treatment of patients suffering from a severe intestinal infection. They treated the control group with standard ORS. Explain why a control consisting of no treatment was not used.
During an investigation into the effect of amylase concentration on the digestion of starch, one student suggested the investigation could be improved by carrying out an experiment with starch but no amylase. Do you agree that this would improve the investigation? Explain your answer.
Appropriate control experiments should be carried out when necessary. Explain why.
Evaluate the usefulness of the range and standard deviation in comparing data about pulse rates from the athletes and non-athletes.
Calculate the percentage increase in the mean number of red blood cells in the athletes’ blood after training at high altitude. Show your working.
A teacher collected class data for the time it took for all the starch to be digested at 60 °C. He then calculated the mean and standard deviation for the data. What information does the standard deviation provide?
Drug A reduces the mean concentration of amylase in the blood. Calculate the percentage reduction in amylase concentration when people with pancreatitis take this drug. Show your working.
Describe and explain the relationship between standard deviation and the reliability of the results.
You put a tube containing the enzyme and a tube containing the substrate in the water bath before you mixed them. The tubes were left in the water bath for five minutes before they were mixed. Explain why this was necessary.
Five minutes may not have been long enough. Suggest how you could find out when they should be mixed.
You left the test tubes in the water bath for 10 minutes before you added the enzyme to the substrate. Explain why.
You put the tubes containing the separate amylase and starch solutions in a water bath for 10 minutes before mixing. Explain why.
You left Tube 1 and Tube A in the water bath before mixing their contents. Explain why.
Temperature affects the rate at which pieces of cut apple go brown. Describe how you would take into account the effect of temperature when investigating the rate at which pieces of cut apple go brown.
Temperature can be an experiment variable. Was this variable controlled during your investigation? Explain your answer.
Investigations that involve growth of bacteria should include the control of temperature. Explain why. You were asked to carry out your investigation at room temperature. Did you use a water bath at room temperature? Give the reason for your answer.
You were told to use a water bath at 60 °C. Explain why a water bath is used.
Did you use a water bath at room temperature? Explain the reason for your choice.
Describe how you would maintain a water bath at 10 o C.