GCSE BIOLOGY 8461/2H Paper 2 Higher Tier Mark scheme

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GCSE BIOLOGY 8461/2H Paper 2 Higher Tier Mark scheme Question Answers Extra information Mark AO / Spec. Ref. 01.1 bacteria fungi allow singular allow mould ignore microbes / germs / d... ecomposers do not accept viruses 1 1 AO1 4.7.2.2 4.7.2.3 01.2 fatty acid(s) 1 AO2 4.7.2.3 4.2.2.1 RPA10 01.3 any one from: • universal indicator (paper / solution) • pH meter allow UI (paper / solution) ignore pH paper unqualified allow pH probe ignore datalogger unqualified ignore Cresol red ignore phenolphthalein / litmus 1 AO1 4.7.2.3 RPA10 01.4 any two from: • volume of milk • exposure to air / oxygen • sterilise test tubes • treatment of milk before investigation • freshness / age of milk (at start) • time of day pH was measured allow amount of milk allow bungs on test tubes allow example such as pasteurised or not allow starting pH of milk 2 AO1 4.7.2.3 RPA10 01.5 almond (milk) 1 AO3 4.7.2.3 RPA10 MARK SCHEME – GCSE BIOLOGY – 8461/2H – JUNE 2020 9 01.6 as temperature increases up to 15 °C the time taken (to reach pH 5) decreases above 15 °C the time taken (to reach pH 5) stays the same allow converse if no other mark awarded allow 1 mark for as temperature increases the time taken (to reach 5 °C) decreases and then stays the same 1 1 AO2 4.7.2.3 RPA10 01.7 any one from: • bacteria / microbes / microorganisms / fungi dividing faster (when warmer) • reactions (in the bacteria) are happening faster (to decay milk) • (because there is) more (kinetic) energy • enzyme activity is higher (at 10 °C than at 5 °C) allow converse if clearly describing 5 °C allow number of bacteria / microbes / microorganisms / fungi increasing (when warmer) allow more bacteria microbes / microorganisms / fungi allow particles move faster allow more collisions between particles allow enzymes work faster ignore enzymes work better 1 AO2 4.7.2.3 4.1.1.6 RPA10 01.8 any two from: • different concentration / type of fat / lipid • different concentration / type of proteins / carbohydrate / sugar • different (amount / type of) bacteria present • may have been pasteurised by a different process • different starting pH allow different amounts of fat / lipid allow different amounts of proteins / carbohydrate / sugar allow may have been treated in different ways (before the investigation) ignore different oxygen concentration 2 AO3 4.7.2.3 RPA10 [Show More]

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