Research: Biology Combined Science 8464 : Past
Paper Questions AQA GCSE
Suggest two reasons why the scientist’s conclusion may not be valid.
A scientist’s conclusion may not be valid if the variables used in the experiment are not
controlled, ensuring influence from other variables instead of the independent variable.
Research bias can also invalidate the conclusion when results are distorted from the truth due
to substandard or unblinded data collection.
A student investigated the effect of different concentrations of sugar solution on pieces of
potato.
This is the method used.
-Cut five pieces of potato.
-Record the starting mass of each piece of potato.
-Place each piece of potato in a different concentration of sugar solution.
-After 24 hours remove the pieces of potato from the solutions.
-Record the final mass of each piece of potato.
-Calculate the change in mass for each piece of potato.
What is the independent variable?
The independent variable is the variable that is not manipulated and is not changed or
influenced by the other variables that are being measured.
The concentration of the sugar solution is used to identify the cause-and-effect relationship with
the dependent variable, the change in mass for each piece of potato.
A student investigated fermentation in yeast.
What volume of carbon dioxide has been collected in the gas syringe in the figure?
Based on the figure, the volume of carbon dioxide that has been collected in the gas syringe is
45 cm3.
A student investigated fermentation in yeast.
This is the method used.
-Mix yeast with sugar solution in a flask.
-Put the flask in a water bath at 35 °C.
-After 10 minutes attach a gas syringe to the flask.
-Record the volume of carbon dioxide collected every 5 minutes for 1 hour.
Why did the student wait 10 minutes before attaching the gas syringe?
The student waited 10 minutes before attaching the gas syringe to allow time for the mixture to
reach 35 °C.
This would allow the yeast with the sugar solution to equilibrate and adapt to the higher
temperature before initiating the absorption of the sugar and fermentation for gas collection.
A student used a potometer to investigate the rate of water uptake in a plant shoot. As the shoot
takes in water the air bubble moves. The rate of water uptake is the distance the air bubble
moves in a given time.
Paper Questions AQA GCSE
Suggest two reasons why the scientist’s conclusion may not be valid.
A scientist’s conclusion may not be valid if the variables used in the experiment are not
controlled, ensuring influence from other variables instead of the independent variable.
Research bias can also invalidate the conclusion when results are distorted from the truth due
to substandard or unblinded data collection.
A student investigated the effect of different concentrations of sugar solution on pieces of
potato.
This is the method used.
-Cut five pieces of potato.
-Record the starting mass of each piece of potato.
-Place each piece of potato in a different concentration of sugar solution.
-After 24 hours remove the pieces of potato from the solutions.
-Record the final mass of each piece of potato.
-Calculate the change in mass for each piece of potato.
What is the independent variable?
The independent variable is the variable that is not manipulated and is not changed or
influenced by the other variables that are being measured.
The concentration of the sugar solution is used to identify the cause-and-effect relationship with
the dependent variable, the change in mass for each piece of potato.
A student investigated fermentation in yeast.
What volume of carbon dioxide has been collected in the gas syringe in the figure?
Based on the figure, the volume of carbon dioxide that has been collected in the gas syringe is
45 cm3.
A student investigated fermentation in yeast.
This is the method used.
-Mix yeast with sugar solution in a flask.
-Put the flask in a water bath at 35 °C.
-After 10 minutes attach a gas syringe to the flask.
-Record the volume of carbon dioxide collected every 5 minutes for 1 hour.
Why did the student wait 10 minutes before attaching the gas syringe?
The student waited 10 minutes before attaching the gas syringe to allow time for the mixture to
reach 35 °C.
This would allow the yeast with the sugar solution to equilibrate and adapt to the higher
temperature before initiating the absorption of the sugar and fermentation for gas collection.
A student used a potometer to investigate the rate of water uptake in a plant shoot. As the shoot
takes in water the air bubble moves. The rate of water uptake is the distance the air bubble
moves in a given time.
