AQA AS BIOLOGY 7401/2 PAPER 2 MARK
SCHEME PRACTICE EXAMINATION 2026
QUESTIONS WITH ANSWERS GRADED A+
◍ 2012 Nov4. (b) Explain how a base substitution mutation, such as GAG to
GTG, can lead to a diseaselike sickle-cell anemia..
Answer: (b) change in the codon (of the mRNA);tRNA with a different
anticodon attaches;(if codon changed) wrong/different amino acid is joined
to peptide/glutamic acid replaced by valine;distorted hemoglobin molecule
alters red blood cell shape/reduces ability to carry oxygen
◍ 2013 TZ26. (a) State the functions of the following organelles of a
eukaryotic animal cell: lysosome, Golgi apparatus, free ribosomes, plasma
membrane, rough endoplasmic reticulum.(b) Distinguish between anaerobic
and aerobic cell respiration in eukaryotes..
Answer: (a) lysosome: (from Golgi apparatus) with digestive enzymes /
break down food/organelles/ cell; Golgi apparatus: site that
processes/modifies/packages and releases proteins; free ribosomes: site of
synthesis of proteins (released to cytoplasm); plasma membrane: controls
entry and exit of materials/substances in cell; rough endoplasmic reticulum:
synthesis and transport of proteins; (both needed) (b) aerobic requires
oxygen(in cytoplasm and) mitochondriaKrebs cyclelarge yield of
ATP/energyCO2 and water (both needed)anaerobicno O2in cytoplasmno
Krebssmall ATP yeildlactate (animals);ethanolCO2 (yeast/plants); (both
needed)
◍ 2010 Nov2. (d) Explain, using one example, how non-disjunction in meiosis
can lead to changes in chromosome number..
Answer: (d) pair of homologous chromosomes moves in same direction/does
not separateduring anaphase I / chromatids move in same direction/do not
, separate duringanaphase II;leaving a cell with an (some) extra
chromosome(s)/missing chromosome(s); an example; (e.g. Down syndrome
/ trisomy 21);
◍ 2011 TZ2 4. (a) State the evidence provided by the karyotype that shows
this person has Down syndrome. (b) Outline how Down syndrome occurs
due to meiosis. (c) Determine, giving a reason, the sex of the person in the
karyotype. (d) Explain briefly why males are more likely to inherit colour
blindness than females.
Answer: (a) three copies/extra copy/trisomy of chromosome/pair 21 (b)
occurs due to non-disjunction; (homologous) chromosome/pairs/sister
chromatids fail to separate; some gametes have an extra chromosome;(c)
male as sex chromosomes different size/both X and Y chromosomes
present(d) gene for colour blindness is carried on X chromosome (sex
linkage); males have only one X chromosome so the allele is always
expressed / absent from Y chromosome; the allele of the gene for colour
blindness is recessive; females must be homozygous to be colourblind /
heterozygous females are carriers but not colourblind;
◍ Paper 1.
Answer: 1 hour and 15 minutes, 40 marks, 40 multiple choice questions.
◍ 2011 Nov 5. (a) Draw a labelled diagram to show the structure of
membranes..
Answer: (a) phospholipid bilayer - with head and tails; hydrophilic /
phosphate / polar heads and hydrophobic / hydrocarbon / fatty acid
/non-polar tails labelled; integral/intrinsic protein - embedded in the
phospholipid bilayer; protein channel - integral protein showing clear
channel/pore; peripheral/extrinsic protein - on the surface;glycoprotein with
carbohydrate attached;(carbohydrate should project outwardlyfrom
membrane protein) cholesterol - shown embedded in bilayer; (must appear
in hydrophobic region) thickness indicated (10 nm);
◍ 2016 Nov3. Define metabolism.(b) Identify the following processes as either
anabolism or catabolism by placing a tick in the correct box.Process
SCHEME PRACTICE EXAMINATION 2026
QUESTIONS WITH ANSWERS GRADED A+
◍ 2012 Nov4. (b) Explain how a base substitution mutation, such as GAG to
GTG, can lead to a diseaselike sickle-cell anemia..
Answer: (b) change in the codon (of the mRNA);tRNA with a different
anticodon attaches;(if codon changed) wrong/different amino acid is joined
to peptide/glutamic acid replaced by valine;distorted hemoglobin molecule
alters red blood cell shape/reduces ability to carry oxygen
◍ 2013 TZ26. (a) State the functions of the following organelles of a
eukaryotic animal cell: lysosome, Golgi apparatus, free ribosomes, plasma
membrane, rough endoplasmic reticulum.(b) Distinguish between anaerobic
and aerobic cell respiration in eukaryotes..
Answer: (a) lysosome: (from Golgi apparatus) with digestive enzymes /
break down food/organelles/ cell; Golgi apparatus: site that
processes/modifies/packages and releases proteins; free ribosomes: site of
synthesis of proteins (released to cytoplasm); plasma membrane: controls
entry and exit of materials/substances in cell; rough endoplasmic reticulum:
synthesis and transport of proteins; (both needed) (b) aerobic requires
oxygen(in cytoplasm and) mitochondriaKrebs cyclelarge yield of
ATP/energyCO2 and water (both needed)anaerobicno O2in cytoplasmno
Krebssmall ATP yeildlactate (animals);ethanolCO2 (yeast/plants); (both
needed)
◍ 2010 Nov2. (d) Explain, using one example, how non-disjunction in meiosis
can lead to changes in chromosome number..
Answer: (d) pair of homologous chromosomes moves in same direction/does
not separateduring anaphase I / chromatids move in same direction/do not
, separate duringanaphase II;leaving a cell with an (some) extra
chromosome(s)/missing chromosome(s); an example; (e.g. Down syndrome
/ trisomy 21);
◍ 2011 TZ2 4. (a) State the evidence provided by the karyotype that shows
this person has Down syndrome. (b) Outline how Down syndrome occurs
due to meiosis. (c) Determine, giving a reason, the sex of the person in the
karyotype. (d) Explain briefly why males are more likely to inherit colour
blindness than females.
Answer: (a) three copies/extra copy/trisomy of chromosome/pair 21 (b)
occurs due to non-disjunction; (homologous) chromosome/pairs/sister
chromatids fail to separate; some gametes have an extra chromosome;(c)
male as sex chromosomes different size/both X and Y chromosomes
present(d) gene for colour blindness is carried on X chromosome (sex
linkage); males have only one X chromosome so the allele is always
expressed / absent from Y chromosome; the allele of the gene for colour
blindness is recessive; females must be homozygous to be colourblind /
heterozygous females are carriers but not colourblind;
◍ Paper 1.
Answer: 1 hour and 15 minutes, 40 marks, 40 multiple choice questions.
◍ 2011 Nov 5. (a) Draw a labelled diagram to show the structure of
membranes..
Answer: (a) phospholipid bilayer - with head and tails; hydrophilic /
phosphate / polar heads and hydrophobic / hydrocarbon / fatty acid
/non-polar tails labelled; integral/intrinsic protein - embedded in the
phospholipid bilayer; protein channel - integral protein showing clear
channel/pore; peripheral/extrinsic protein - on the surface;glycoprotein with
carbohydrate attached;(carbohydrate should project outwardlyfrom
membrane protein) cholesterol - shown embedded in bilayer; (must appear
in hydrophobic region) thickness indicated (10 nm);
◍ 2016 Nov3. Define metabolism.(b) Identify the following processes as either
anabolism or catabolism by placing a tick in the correct box.Process
