June 20101 A student carried out an investigation into the
variables affecting the permeability of beetroot cell membranes.
Pieces of beetroot were placed into tubes containing distilled
water. The student then used a colorimeter to measure the intensity
of red colouration in the distilled water. (a) (i) Suggest one
factor that affects the permeability of the beetroot cell membrane.
Write a hypothesis for this investigation that the student could
test.(2)Factor................................................................................................................................................Hypothesis
.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
(ii) Use your biological knowledge and understanding to explain and
justify this
hypothesis.(3)................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
(b) (i) State two factors that need to be controlled in this
investigation.(2)1........................................................................................................................................................2........................................................................................................................................................
(ii) Suggest how one of the factors you have stated in (b)(i) could
be controlled. If this factor had not been controlled, what effect
would it have on the results? (2)How the factor is
controlled..........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................Effect
on the results if this factor is not
controlled................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
(c) Describe how you could reduce systematic errors in the
measurements of the dependent variable in this
investigation.(2)................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
(Total for Question 1 = 11 marks)
January 20111 Agar plates spread with a suitable culture of
bacteria can be used to test the effectiveness of different
antibiotics. (a) Describe how to investigate the effect of
different types of antibiotic (the independent variable) on
bacteria. Include details of a suitable dependent variable and how
it can be
measured.(6)........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
(b) (i) State two variables, other than the dependent and
independent variable, which could affect the
investigation.(2)1........................................................................................................................................................2........................................................................................................................................................
(ii) Suggest how one of the variables you have stated in (b)(i)
could be controlled.
(1)............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
(c) Give two ways in which this investigation should be carried out
safely.(2)..................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(d)
To treat a bacterial infection, an antibiotic must be effective
against the bacteria. Suggest one other factor that may need to be
considered by a doctor when prescribing an antibiotic to treat a
patient with a bacterial
infection.(1)................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
(Total for Question 1 = 12 marks)
May 20111 Many scientists are concerned about the effect climate
change could have on the development of organisms. Climate change
could have an effect on the yield of many important farmed foods,
such as maize, wheat, rice and fish.(a) Describe an experiment to
investigate the effect of temperature (the independent variable) on
the development of organisms such as seedlings or brine shrimps.
Include details of a suitable dependent
variable.(5)........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
(b) (i) State two variables, other than temperature, which could
affect this
investigation.(2)1........................................................................................................................................................2........................................................................................................................................................
(ii) Choose one of the variables from (i). Suggest how this
variable could have been controlled. Describe what effect it could
have had on the results if it had not been
controlled.(2)Variable............................................................................................................................................How
to control the variable
................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................Effect
on the results if the variable had not been controlled
....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(c)
Some plants are adapted to live in low environmental temperatures.
When the environmental temperature increases the gross primary
productivity increases, but the net primary productivity decreases.
This may cause the yield of some crops to decrease. Explain why an
increase in environmental temperature causes the yield of some
crops to decrease.
(4)......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
(Total for Question 1 = 13 marks)
January 20121 Seeds contain a plant embryo and a food supply.
Cell growth in the seeds will begin when the temperature and
moisture conditions are favourable. During cell growth, enzymes
break down the stored food supply and ATP is generated by
respiration.(a) Describe an experiment to investigate the effect of
temperature (the independent variable) on the rate of respiration
in
seeds.(5)........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(b)
(i) State two variables, other than temperature, which could affect
the
investigation.(2)1........................................................................................................................................................2........................................................................................................................................................(ii)
Choose one of the variables from (b)(i). Suggest how this variable
could have been controlled. Describe what effect it could have had
on the results if it had not been
controlled.(2)Variable.............................................................................................................................................How
to control the variable
................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................Effect
on the results if the variable had not been controlled
....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(c)
If the seeds had not been exposed to any oxygen during this
investigation, suggest the effect this may have on the results.
Give an explanation for your
answer.(3)......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
(Total for Question 1 = 12 marks)
May 20121 The unwanted plants growing in a field of cereal crops
are called weeds. Selective weedkillers can be used on fields of
cereal crops. These kill broad-leaved weeds, without harming the
cereal plants. (a) Describe an experiment to investigate the effect
of a new selective weedkiller in a field containing cereal plants
and broad-leaved
weeds.(6)........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
(b) (i) Suggest two abiotic factors that are variables in the
investigation.(2)1........................................................................................................................................................2........................................................................................................................................................
(ii) Choose one of the variables from (b)(i). Suggest how this
variable could be taken into account or have been controlled.
Describe what effect this variable could have had on the results.
(2)Variable.............................................................................................................................................How
the variable could be taken into account or controlled
................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................Effect
of the variable on the results
...............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
(c) Suggest how a selective weedkiller, containing a plant growth
regulator such as IAA, may be able to kill broad-leaved
weeds.(2)................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
(Total for Question 1 = 12 marks)
January 20131 Many fruits contain vitamin C. Fruits can decay
quickly when stored at room temperature. They are therefore
sometimes stored in a refrigerator or freezer. (a) Describe an
experiment to investigate the effect of storage temperature on the
vitamin C content of one type of
fruit.(5)..................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
(b) (i) State two variables which need to be controlled in this
investigation.(2)1........................................................................................................................................................2........................................................................................................................................................
(ii) Choose one of the variables from (b)(i) above. Suggest how
this variable can be controlled. Describe what effect it could have
on the results if it is not
controlled.(2)Variable.............................................................................................................................................How
to control the variable
................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................Effect
on the results if the variable is not controlled
................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
(c) Suggest why storing fruit at low temperature slows down
decay.(3)......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
(Total for Question 1 = 12 marks)
May 20131 John thought that there was a difference in breathing
when lying down compared with when sitting on a chair. He decided
to test this, using traces from a spirometer. (a) Describe how he
could use data from spirometer traces to compare breathing when
lying down and when sitting on a
chair.(4)........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(b)
(i) State two variables which need to be controlled to provide
valid spirometer
traces.(2)1........................................................................................................................................................2........................................................................................................................................................
(ii) Choose one of the variables from (b)(i) above. Suggest how
this variable can be controlled. Describe what effect this variable
could have on the data from the spirometer traces if it is not
controlled.(2)Variable.............................................................................................................................................How
to control the variable
......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................Effect
on the data from the spirometer traces if this variable is not
controlled.................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
(c) Suggest how breathing is controlled by the nervous system in
response to changing position from lying down to sitting on a
chair.(4)......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
(Total for Question 1 = 12 marks)
January 20141 Lemurs are primates found on the island of
Madagascar. At least 33 different species of lemur are living on
the island today. Scientists would like to know how closely related
the different species of lemur are.In one study, the scientists
collected tissue samples from several individuals of eachspecies.
For each sample, they examined the DNA sequences of five different
genes.The polymerase chain reaction (PCR) was used to amplify the
DNA in the samples.(a) Describe how to amplify a strand of DNA
using the polymerase chain reaction
(PCR).(5)....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(b)
An enzyme is used in the amplification process. Describe two
properties of this enzyme that are relevant to its biological
activity in this
process.(2)1............................................................................................................................................................................................................................................................................................................................................................................................................................................................................2............................................................................................................................................................................................................................................................................................................................................................................................................................................................................(c)
Temperature is an important variable in the PCR.Choose one step in
the process you described in part (a) and explain why changing the
reaction temperature might reduce the production of DNA in this
reaction.(2)Step...................................................................................................................................................Explanation...............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(d)
Suggest an explanation for each of the following statements.(i) The
scientists collected and analysed samples from more than one
individual of each
species.(2)................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
(ii) For each sample, the scientists examined the DNA sequence of
five different
genes.(2)................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
(Total for Question 1 = 13 marks)
June 20141 Snails can respond to a variety of stimuli, including
touch. When a snail experiences an unfamiliar stimulus, it will
withdraw into its shell. After repeated exposure to the same
stimulus, the snail will stop responding to the stimulus. This
behavior is called habituation.
A snail magnification x2(a) Describe how you could investigate
the habituation of a snail to a stimulus.
(5)......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
(b) (i) State two variables, other than the stimulus, which could
affect the
investigation.(2)1........................................................................................................................................................2........................................................................................................................................................
(ii) Choose one of these variables. Suggest how this variable could
be controlled.Describe the effect the variable could have on the
results if it is not controlled.
(2)Variable.............................................................................................................................................How
to control the
variable................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................Effect
on the results if the variable is not controlled
................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
(c) Suggest how calcium ions are involved in habituation in snails.
(4)......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
(Total for Question 1 = 13 marks)
January 2015
1 A seed contains an embryo and a food supply. A seed will
germinate when it is placed in suitable conditions. The ATP
required for growth and germination is provided by respiration. (a)
Describe an experiment to determine the effect of temperature on
the rate of respiration in germinating seeds. (5)
........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(b)
(i) State two variables, other than temperature, that could affect
this investigation. (2)
1........................................................................................................................................................
2........................................................................................................................................................
(ii) Suggest how one of the variables you have stated in (b)(i)
could be controlled. Describe what effect it could have on the
results if it was not controlled. (2)
Variable.............................................................................................................................................How
to control the
variable................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................Effect
on the results if the variable is not
controlled................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
(c) When seeds are placed in conditions suitable for germination,
there is a delay of several hours before respiration can be
detected. Suggest an explanation, in terms of metabolic processes,
that might account for this delay. (3)
......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
(Total for Question 1 = 12 marks)