A-LEVEL
Human Biology
HBIO1
Mark scheme
2405
JUNE 2016
Version: 1.0 Final
Mark schemes are prepared by the Lead Assessment Writer and considered, together with the
relevant questions, by a panel of subject teachers. This mark scheme includes any amendments
made at the standardisation events which all associates participate in and is the scheme which was
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scripts: alternative answers not already covered by the mark scheme are discussed and legislated for.
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MARK SCHEME – A-LEVEL HUMAN BIOLOGY – HBIO1 – JUNE 2016
Question
Answers
Mark
1a
1. Plasma membrane / cell surface membrane;
2. Ribosome ;
1b
1. Cell wall;
2. Plasmid;
3. Capsule;
2a
3 max
1. Less (likely to suffer from) obesity;
2. Less (likely to suffer from type 2) diabetes;
3a
1 mark for each correct row ; ; ; ;
Mycobacterium

Accept:
mesosome
70s ribosome
circular DNA
Ignore:
free DNA
flagellum
1&2 Accept
correct named
vitamin or mineral
Ignore references
to glucose/sugars
2b
HIV
2
2 max
1.(Good) source of vitamins;
2. (Good) source of minerals;
3. Low in fats/saturate fats/cholesterol;
4. (High in) fibre;
5. Contain antioxidants;
Additional
Comments /
Guidance
Salmonella
2
Allow less (likely
to suffer from)
..MI/CHD;
..high blood
pressure;
..stroke;
..cancer;
Ignore unqualified
references to
heart disease.
4



3b
1. Antibiotics interfere with (bacterial) metabolism
/ prevent cell wall synthesis/protein synthesis;
2. Viruses do not have metabolism/cell wall / do not
synthesise proteins;
2
1. Allow ‘Interfere
with DNA
replication’
3 of 9
MARK SCHEME – A-LEVEL HUMAN BIOLOGY – HBIO1 – JUNE 2016
Question
4a
Answers
1. (Blood) Pressure high;
2. Higher than water potential difference;
3. Capillary walls/endothelium partially
permeable;
Mark
3 max
4. Water and small molecules forced out;
4b
1. Higher/less negative water potential/WP/Ψ
in blood/capillaries because it contains less
protein;
2 Less water reabsorbed by osmosis / less
water reabsorbed because of lower water
pressure/WP/Ψ gradient;
5a
Induced fit;
5b
1. Substrate enters/occupies/ fits into /binds
with active site;
2. To form an enzyme substrate complex;
3. Active site/enzyme changes shape to fit
substrate (exactly);
4. Substrate broken into two products/two
products released;
5. Enzyme returns to original shape;
Additional Comments /
Guidance
3. Accept good
descriptions of partially
permeable
4. Must have idea of
forced – reject diffuse.
Accept correct named
examples of small
molecules
2
2. Ignore tissue fluid
reabsorbed. Reject tissue
fluid/small molecules
reabsorbed by osmosis.
1
Reject lock and key
Ignore references to
collisions
4 max
5c
Enzyme unchanged/returns to original shape
(at end of reaction);
1
Accept ‘enzyme can be
reused’.
5d
1. Breaks/changes hydrogen/ionic bonds;
2
1. Ignore breaks/changes
sulfur/disulfide bonds
2. Changes shape of active site / changes
tertiary structure of enzyme / denatures
enzyme;
4 of 9
MARK SCHEME – A-LEVEL HUMAN BIOLOGY – HBIO1 – JUNE 2016
Question
Answers
6a
Antibodies/antibody received from
mother/via placenta;
6b
(Active immunity)
1. Baby/body/individual makes antibodies;
2. Memory cells made;
3. (In) response to
antigen/microorganisms/pathogens;
4. Longer lasting than passive immunity;
6c
Answer in range 68 750 to 69 000;;
6d
1. From 1956/ after vaccine introduced /
when percentage vaccinated rises there
is a fall in number of cases;
2. When percentage of children vaccinated
falls number of cases increase;
3. Correct use of 2 or more pieces of data
from y axis/axes of graph to support
above statement(s);
7a
Mark
1
2 max
2
3
Additional Comments /
Guidance
Ignore references to breast
milk/lactation.
Accept converse as answer
clearly refers to passive
immunity.
1 mark for correct values
derived from graph but error
in/no calculation
If 1 and 2 not given allow 1
mark for ‘Inverse relationship
between percentage
vaccination and number of
cases’
1. To remove (liver) tissue/cells/
(undigested)protein/enzyme;
2. That might obscure spots/ give
additional spots / that might block
pipette / to give solution that can be
loaded;
2
7b
Hydrolysis;
1
Reject hydration
Reject hydrogenation
7c
Amino acids;
1
Accept peptides/oligopepties/
dipeptides
Ignore polypeptides
Question
Answers
2. Ignore unqualified
references to avoid affecting
results
Mark
Additional Comments /
Guidance
5 of 9
MARK SCHEME – A-LEVEL HUMAN BIOLOGY – HBIO1 – JUNE 2016
7d
Answer in range 0.88 to 0.92;;
7e
1.Carry out chromatography of unknown
substance and known substances
together/on same chromatogram;
2. Compare Rf values / if two spots travel
the same distance they are the same
substance;
OR
1. Compare Rf value with reference
values/tables/databases/ Rf values of
known substances;
2. Under same conditions / using same
solvent;
8a
8b
1. (Initial) High pressure because blood
pumped/pushed/forced into arteries by
ventricles/heart;
2. (In arteries) Rise and fall of pressure
due to contraction and relaxation of
ventricle/heart;
3. Variation in pressure decreases along
arteries as less elastic tissues/less
recoil;
4. Pressure falls in arteries/capillaries/
pressure lower in capillaries (than in
arteries) because (much) greater (total)
cross sectional area;
5. Pressure lower in capillaries (than in
arteries) because of fluid loss;
1. Low speed of blood flow;
2. So more time for exchange;
OR
1. Larger cross-sectional area;
2. For diffusion;
OR
1.Larger cross-sectional area means many
capillaries;
2. So no cell far from a capillary/short
diffusion pathways;
2
1 mark for distances origin to
solvent front in range 91 to 92
mm and origin to midpoint or
leading edge of B in range 81
to 84 mm, but no/error in
calculation
2
4 max
2
Ignore references to thin walls
6 of 9
MARK SCHEME – A-LEVEL HUMAN BIOLOGY – HBIO1 – JUNE 2016
Question
Answers
8c
Veins have smaller (total) cross sectional
area ;
9a
1. In CF, CFTR protein tertiary
structure/shape is altered/different;
2. CFTR protein is unable to transport
chloride ions / is unable to fit into cell
surface membrane;
3. (so) Chloride ions not taken up by sweat
duct cells / remain in sweat/not returned
to blood;
9b
9c
1. Large difference between mean
concentration in CF and non-CF / mean
concentration much larger in CF than in
non-CF;
2. SDs do not overlap;
3. To confirm diagnosis need medical
examination / need to check whether
other (named) signs present / there
might be other causes of high
concentration of chloride (ions) in sweat;
1. Thick/sticky/viscous mucus blocks the
pancreatic duct;
2. Pancreatic enzymes unable to get into
gut;
3. Enzymes (from capsules) digest food;
4. So nutrients can be absorbed/used for
growth;
Mark
Additional Comments /
Guidance
1
3
1. Ignore references to CFTR
gene shape
2. Reject CFTR gene
transports chloride ions
1. Accept synonyms for
‘large’ and ‘much’
3
3. Accept ‘symptoms’ for
‘signs’
3 max
4. Accept named nutrients
Ignore food/protein/energy
absorbed
7 of 9
MARK SCHEME – A-LEVEL HUMAN BIOLOGY – HBIO1 – JUNE 2016
Question
Answers
Mark
10 a
1. Salt makes water potential/WP/Ψ (of food)
lower/more negative;
2. Water moves out of microorganisms by
osmosis/from a higher water potential;
3. Microorganisms die/unable to grow/reproduce;
3
10 b
1. (People less likely to notice) change in
flavour/taste;
2. (so) People less likely to stop buying products;
10 c
1. Blockage/narrowing/reduced blood flow in
coronary artery/artery supplying heart
muscle/cardiac muscle/myocardium;
2. (by) Atheroma/cholesterol/plaque/fatty
deposits;
3. (atheroma causes) Turbulence/swirling eddies
(in blood);
4. Thrombus/clot;
5. No/little oxygen reaches (part of) heart
muscle/cardiac muscle/myocardium;
6. Heart muscle cells/tissue/myocardium die(s);
7. Heart unable to pump (sufficient) blood /
unable to supply (sufficient) oxygen to rest of
body;
8. Tissues/organs die;
10 d
29.41/29.4;;
10 e
1. High (blood) pressure damages (lining of)
arteries;
2. Cholesterol/fatty substances/foam
cells/calcium/plaque deposited (in damaged
area);
3. Forms atheroma (which narrows arteries);
4. Formation of thrombus/clot (at damaged area)
Additional Comments /
Guidance
2
1. Ignore references to
artery unqualified
6 max
5&7. Ignore references to
glucose
8. Accept named organs
2
4
1 mark for 29
1 mark if no/incorrect
answer but working shows
8.5 - 6 or 2.5
8.5
8.5
Accept high blood
pressure may contribute to
formation of aneurysms.
3&4 must be in context of
consequence of high BP
8 of 9
MARK SCHEME – A-LEVEL HUMAN BIOLOGY – HBIO1 – JUNE 2016
Question
10 f
Answers
1. Less smoking / fewer smokers / people
stopping smoking;
2. A specified relevant improvement in diet e.g.
less fat/sugar/fewer calories;
Mark
Additional Comments /
Guidance
3
2. Ignore unqualified
references to
balanced/healthy diet
3. Ignore less drinking
4. accept examples
3. Reduced alcohol intake;
4. More exercise;
Ignore references to less
stress.
Ignore references to
medical factors e.g statins
Total
80
9 of 9