Q1.
One factor that may affect body mass is metabolic rate.
(a)     (i)      What is meant by metabolic rate ?
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(1)
(ii)     Metabolic rate is affected by the amount of activity a person does.
Give two other factors that may affect a person’s metabolic rate.
1. ____________________________________________________________
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2. ____________________________________________________________
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(2)
(b)     Predicted early death is the number of years that a person will die before the mean age of death for the whole population. The predicted early death of a person is affected by their body mass.
Scientists have calculated the effect of body mass on predicted early death.
The graph shows the results of the scientists’ calculations.
 
Ideal body mass
The number of times above or below ideal body mass is given by the equation:
 
In the UK the mean age of death for women is 82.
A woman has a body mass of 70 kg. The woman’s ideal body mass is 56 kg.
(i)      Use the information from the graph to predict the age of this woman when she dies.
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Age at death = ___________ years
(2)
(ii)     The woman could live longer by changing her lifestyle.
Give two changes she should make.
1. ____________________________________________________________
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2. ____________________________________________________________
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(2)
(Total 7 marks)
Q2.
(a)     Use words from the box to complete the equation for aerobic respiration.
 
alcohol	glucose	lactic acid	water	
______________ + oxygen   carbon dioxide + ______________ (+ energy)
(2)
(b)     Some students investigated the effect of temperature on the rate of aerobic respiration in earthworms.
The diagram shows the apparatus the students used.
When the tap is closed, the bead of liquid moves to the left as the earthworms take in oxygen.
 
The students put the test tube into a water bath at 20°C for 10 minutes.
They left the tap open during this time.
Why did the students put the test tube in the water bath at 20°C for 10 minutes?
Tick ( ) one box.
 
Because the air contains more oxygen at 20°C.		
Because the air contains less carbon dioxide at 20°C.		
So the earthworms’ body temperature would change to 20°C.		
(1)
(c)     The students then:
•         closed the tap
•         started a stopwatch
•         recorded the position of the bead of liquid every 2 minutes for 10 minutes
•         repeated the experiment at 10°C.
The graph shows the students’ results.
 
Time in minutes
(i)      How much oxygen did the earthworms take in during the 10 minutes at 20°C?
Use information from the graph to work out your answer.
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Volume of oxygen taken in = ___________________ mm3
(2)
(ii)     The earthworms took in this volume of oxygen in 10 minutes.
Use your answer from part (c)(i) to calculate how much oxygen the earthworms took in each minute.
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Volume of oxygen taken in = _______________________ mm3 per minute
(1)
(iii)    The earthworms took in less oxygen each minute at 10°C than they took in at 20°C.
Explain why.
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(2)
(d)     When drawing the line on the graph for the experiment at 10°C, the students ignored the reading at 8 minutes.
(i)      Suggest why they ignored the reading at 8 minutes.
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(1)
(ii)     One student suggested they should repeat the experiment twice more at each temperature.
How would repeating the experiment improve the investigation?
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(1)
(Total 10 marks)
Q3.
(a)     Yeast cells can respire anaerobically.
The equation for anaerobic respiration in yeast is: 
glucose   alcohol + carbon dioxide (+ energy)
Give one way in which anaerobic respiration in yeast cells is different from anaerobic respiration in human muscle cells.
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(1)
(b)     Yeast can use other types of sugar instead of glucose. 
Some scientists investigated the effect of three different types of sugar on the rate of anaerobic respiration in yeast.
The scientists:
•        used the apparatus shown in Diagram 1 with glucose sugar
•        kept the apparatus at 20 °C
•        repeated the investigation with fructose sugar and then with mannose sugar
•        repeated the investigation with water instead of the sugar solution.
Diagram 1
 
(i)      Give two control variables the scientists used in this investigation.
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(2)
(ii)     The graph shows the scientists’ results.
 
             Time in minutes
From this information, a company decided to use fructose to produce alcohol and not mannose or glucose.
Explain the reason for the company’s choice.
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(2)
(Total 5 marks)
Q4.
All living cells respire.
(a)     Respiration transfers energy from glucose for muscle contraction.
Describe how glucose from the small intestine is moved to a muscle cell.
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(2)
(b)     The diagram below shows an experiment to investigate anaerobic respiration in yeast cells.
 
What is the purpose of the liquid paraffin in Tube A?
 
Tick one box.	 	
To prevent evaporation		
To stop air getting in		
To stop the temperature going up		
To stop water getting in		
(1)
(c)     The indicator solution in Tube B shows changes in the concentration of carbon dioxide (CO2).
The indicator is:
•        blue when the concentration of CO2 is very low
•        green when the concentration of CO2 is low
•        yellow when the concentration of CO2 is high.
What colour would you expect the indicator to be in Tube B during maximum rate of anaerobic respiration?
 
Tick one box.	 	
Blue		
Green		
Yellow		
(1)
(d)     Suggest how the experiment could be changed to give a reproducible way to measure the rate of the reaction.
Include any apparatus you would use.
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(2)
(e)     Compare anaerobic respiration in a yeast cell with anaerobic respiration in a muscle cell.
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(3)
(Total 9 marks)
Q5.
The diagram shows a fermenter. This fermenter is used for growing the fungus 
Fusarium.
Fusarium is used to make mycoprotein.
 
(a)     Bubbles of air enter the fermenter at A. 
Give two functions of the air bubbles.
1. _________________________________________________________________
___________________________________________________________________
2. _________________________________________________________________
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(2)
(b)     Why is glucose added to the fermenter?
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(1)
(c)     The fermenter is prevented from overheating by the cold water flowing in through the heat exchanger coils at C.
Name the process that causes the fermenter to heat up.
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(1)
(d)     It is important to prevent microorganisms other than Fusarium growing in the fermenter.
(i)      Why is this important?
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(1)
(ii)     Suggest one way in which contamination of the fermenter by microorganisms could be prevented.
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(1)
(e)     Human cells cannot make some of the amino acids which we need. We must obtain these amino acids from our diet.
The table shows the amounts of four of these amino acids present in mycoprotein, in beef and in wheat.
 
Name of 
amino acid	Amount of amino acid per 100 g 
in mg	Daily amount 
needed by a 
70 kg human 
in mg	
	Mycoprotein	Beef	Wheat		
Lysine	910	1600	300	840	
Methionine	230	500	220	910	
Phenylalanine	540	760	680	980	
Threonine	610	840	370	490	
A diet book states that mycoprotein is the best source of amino acids for the human diet.
Evaluate this statement.
Remember to include a conclusion in your evaluation.
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(4)
(Total 10 marks)

Mark schemes
Q1.
(a)     (i)      rate of chemical reactions (in the body)
1
(ii)     any two from:
•        heredity / inheritance / genetics
•        proportion of muscle to fat or (body) mass
allow (body) weight / BMI
•        age / growth rate
•        gender
accept hormone balance or environmental temperature
ignore exercise / activity
2
(b)    (i)      77
correct answer with or without working gains 2 marks
allow 1 mark for 70 / 56 or 1.25 or 5
2
(ii)     increase exercise
accept a way of increasing exercise
1
reduce food intake
accept examples such as eat less fat / sugar
allow go on a diet or take in fewer calories
ignore lose weight
ignore medical treatments such as gastric band / liposuction
1
[7]
Q2.
(a)     LHS – glucose
1
RHS – water
allow H2O / H20
1
(b)     so the earthworms’ body temperature would change to 20°C
1
(c)     (i)      56 or 55 or 54
if incorrect answer given accept 60 - 5 for 1 mark
or 60 – 6 for 1 mark
or 60 – 4 for 1 mark
2
(ii)     one-tenth of answer to (c)(i) eg 5.5
1
(at 10°C / lower temperature):
lower rate of respiration
allow chemical reactions slower or enzymes less active
ignore breathing
do not allow anaerobic
1
worms less active / worms release less energy / worms use less energy
1
(d)     (i)      anomalous result / not in line with other data / does not fit the pattern
1
(ii)     more representative / more reliable / can check ‘repeatability’ / see if get similar values / identify anomalies
ignore valid / more fair
ignore reproducible
ignore ‘to remove’ anomalies
do not accept more accurate or more precise
1
[10]
Q3.
(a)     in yeast:
’it’ equals yeast
makes alcohol / makes CO2 / does not make lactic acid
do not allow uses / involves alcohol / CO2
1
(b)     (i)      any two from:
allow amount of yeast
•        volume of yeast / suspension
•        volume of sugar / solution
•        concentration of sugar
         amount of sugar = max 1 for sugar
•        temperature
(total) volume = 1 mark if no other volume
ignore concentration of yeast
2
(ii)     most / more CO2 given off with fructose or
’it’ equals fructose
faster CO2 production
or
faster respiration
allow faster fermentation
1
do not allow aerobic respiration
so (rate of) alcohol production will be greatest / more (with fructose)
1
[5]
Q4.
(a)     glucose is absorbed by diffusion into the bloodstream
1
then blood delivers glucose to muscles in capillaries
1
(b)     to stop air getting in
1
(c)     yellow
1
(d)     collect the CO2 / gas with a measuring cylinder / gas syringe
1
(volume collected) in a certain time using a timer / watch
1
(e)     yeast produces ethanol but muscles produce lactic acid
marks can be awarded from correct word or balanced symbol equations
1
yeast produces CO2 but muscles do not
answers must be comparative
1
both release small amounts of energy
1
ignore both occur without oxygen
[9]
Q5.
(a)    circulating / mixing / described or temperature maintenance
1
supply oxygen
or for aerobic conditions
or for faster respiration
do not allow oxygen for anaerobic respiration
1
(b)     energy supply / fuel / use in respiration
do not allow just food / growth
ignore reference to aerobic / anaerobic
or material for growth / to make mycoprotein
1
(c)     respiration
allow exothermic reaction
allow catabolism
ignore metabolism
ignore aerobic / anaerobic
1
(d)    (i)      any one from:
•        compete (with Fusarium) for food / oxygen or reduce yield of Fusarium
•        make toxic waste products or they might cause disease / pathogenic or harmful to people / to Fusarium
do not allow harmful unqualified
1
(ii)     steam / heat treat / sterilise fermenter (before use)
not just clean
or
steam / heat treat / sterilise
glucose / minerals / nutrients / water (before use)
or
filter / sterilise air intake
or
check there are no leaks
allow sterilisation unqualified not just use pure glucose
1
(e)     any three from:
•        beef is best or beef is better than mycoprotein
•        mycoprotein mainly better than wheat
•        more phenylalanine in wheat than in mycoprotein
allow equivalent numerical statements
•        but no information given on other amino acids / costs / foods
3
overall conclusion:
statement is incorrect because
either
it would be the best source for vegetarians
or
for given amino acids, beef is the best source
or
three foods provide insufficient data to draw a valid conclusion
1
[10]