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(a)
225 (±5)
(b)
(c)
(d)
(a)
decreased for the first four / five months / up to June / July / initially;
increased in September / October;
decline in November;
showed day to day fluctuation;
slight increase in May and June / April and May;
less variation / plateaus July to August / September;
Simple “yes / no” not acceptable.
the data does not support the hypothesis;
the increase in asthma admissions does not immediately
follow a rise in pollen /
hospital admissions fall whilst pollen levels remain
constant in March to August;
or
the data does support the hypothesis;
the main increase in asthma admissions follows
a short time after a rise in pollen;
inflammation of airways / bronchioconstriction /
constriction of airways / increased mucus secretion in airways /
coughing / lack of breath
height 0.54 m: 60–79 cm / 0.60–0.79 m (from the plant)
and height 10.8 m: 0–2.9 m
(from the plant);
Units needed for both parts of the answer.
(b)
(c)
the greater the height from which the seed fell,
the further it travelled from the parent plant
1
3 max
2
1 max
1
1
at the greater height:
seed can catch the wind to travel further / updrafts /
more wind at greater height;
farther to the ground and does not travel straight down /
more time to be blown before hitting the ground;
at lower height:
seed can fall straight down;
seed can hit downdraft and fall faster;
Any point must explain the difference in distance
travelled from the two heights.
2 max
(d)
Agrostis stolonifera
1
(e)
Poa trivialis
1
(f)
Poa produces seed earliest in the summer / June;
Holcus produces most seed in July;
Agrostis and Festuca produce seed in (late July to) August;
Holcus and Poa have a peak time of seed fall /
short period of seed fall;
Agrostis and Festuca may continue to increase in
seed production to September;
Accept any of these points made conversely as an alternative.
(g)
(h)
(i)
(j)
3 max
Award [1] each for any two of the following.
to avoid predation /
disperse at times when other species are dispersing their seeds;
to avoid competition;
late in the year to allow seeds to germinate over winter /
better germination conditions;
better dispersal conditions / more wind / animals for dispersal;
photoperiod – required day length for flowering;
more energy stored at the end of the summer for seed production;
more light / warmth / better conditions for seedling photosynthesis /
growth;
2 max
Award [1] each for any two of the following.
tropical fruits have higher lipid content than temperate fruits;
temperate fruits (80%) have greater carbohydrate
content than tropical fruits (55%);
protein levels are similar in both groups of fruits /
slightly higher in temperate fruits
than tropical fruits;
(must make it clear that the difference is slight)
2 max
mistletoe;
high proportion of lipid and carbohydrate
(lipid has approximately twice the energy content
of protein and carbohydrate);
2
Award [1] for advantage and [1] for disadvantage.
animal dispersal advantage:
travel further / digestion cracks seed coat for better germination /
deposited in feces with organic matter /
better in areas with little wind;
animal dispersal disadvantage:
predation / seeds eaten / deposited in poor environment /
buried too deep / buried too shallow (if deposited with feces) /
animal might become extinct / scarce;
(a)
6 ( 2) (%);
(b)
(c)
2 max
1
only ripe transcribe PG mRNA / ripe tomatoes produce more PG mRNA
than unripe;
band at 1.77 kb only in ripe;
2 max
no effect on unripe fruit;
band at 1.77 kb much smaller in transformed / less PG mRNA produced in
transformed ripe fruit;
antisense mRNA combines with sense mRNA;
inactivating the translation / less translation;
less PG to solubilize pectin of wall;
fruit takes longer to ripen;
3 max
(a)
the site (on the surface of an enzyme) to which substrate(s) bind / the site (on the
enzyme) where it catalyzes a chemical reaction;
(b)
bring substrates close together in active site / in correct orientation;
forms enzyme-substrate complex / substrate(s) bind to active site;
lowers the activation energy for the reaction;
weakens bonds in the substrate;
1
2 max
(c)
enzymes have an optimal pH;
lower activity above and below optimum pH / graph showing this;
too acidic / basic pH can denature enzyme;
change shape of active site / tertiary structure altered;
substrate cannot bind to active site / enzyme-substrate complex cannot form;
hydrogen / ionic bonds in the enzyme / active site are broken / altered;
3 max
(d)
energy storage / source of energy / respiration substrate;
(heat) insulation;
protection (of internal organs);
water proofing / cuticle;
buoyancy;
(structural) component of cell membranes;
electrical insulation by myelin sheath;
(steroid) hormones;
glycolipids acting as receptors;
Three correct [2], one or two correct [1].
2 max
Use one tick to mark the first one or two correct answers. Use a second tick to
mark the third correct answer. Mark the first three answers only.
(a)
small cells have larger ratio (than larger cells) / ratio decreases as size increases;
surface area / membrane must be large enough to absorb nutrients / oxygen /
substances needed;
surface area / membrane must be large enough to excrete / pass out waste
products;
need for materials is determined by (cell) volume;
cell size is limited (by SA / vol ratio) / cells divide when they reach a certain
size;
reference to diffusion across / through membrane / surface area;
3 max
(b)
Award [1 max] for each organelle. Mark first answer only.
(i)
translation / produces polypeptides / proteins / protein synthesis;
(ii)
support of ribosomes / site of protein synthesis / synthesis of
proteins for secretion / folding of polypeptides;
(iii)
produces glycoproteins / processing of proteins / forms lysosomes
/ formation of vesicles (for exocytosis);
3 max
(c)
Award [1]for each of the following pairs.
Mark first answer only in boxes 1, 2 and 3.
prokaryotic cells
nucleoid / no nucleus / nuclear membrane
naked DNA / no histones
no mitochondria
no Golgi / no ER
circular DNA
no / very few membrane-bound organelles
organelles;
ribosomes smaller / 70S
no mitosis / meiosis
flagella lack internal microtubules
(9+2);
eukaryotic cells
vs.
vs.
vs.
vs.
vs.
vs.
nucleus / nuclear membrane;
NA associated with protein / histone;
mitochondria present;
Golgi / ER present;
linear DNA;
membrane-bound
vs. ribosomes larger / 80S;
vs. mitosis / meiosis;
vs. flagella have microtubules
3 max
Allow [1] only for a similarity.
(a)
more than one codon / base triplet codes for an amino acid
(b)
may lead to an understanding of genetic / inherited diseases / conditions;
may lead to the production of gene probes to detect carriers of genetic
diseases;
may lead to the production of pharmaceuticals based on DNA sequences;
study of similarities / differences between human race / population;
find location of genes / produce a complete gene map;
study of human origins / migration / relationships with other species;
(c)
reverse transcriptase catalyzes the production of DNA from RNA
(d)
Award [1 max] for use in diagnosis and [1 max] for use in treatment.
diagnosis:
1
2 max
1
detection of (antibodies to) HIV;
detection of HCG / pregnancy test kits;
detection of cardiac enzyme in suspected heart attacks;
detection of tissue / blood type;
testing for (different strains of) malaria;
ELISA test;
treatment:
targeting cancer cells with attached drugs;
treatment of rabies / Ebola / lymphoma
destroying T-cells to reduce rejection of transplants;
2 max
[6]
(a)
high pressure in afferent arterioles;
leads to ultrafiltration in the glomerulus / through fenestrated
capillaries in the glomerulus;
drains through the Bowman’s capsule to the proximal convoluted tubule;
(b)
(c)
(d)
2 max
(i)
glucose / amino acids
1
(ii)
water by osmosis;
salts by active transport / facilitated diffusion;
2
size of image
49000 m
or
or 4.9 cm scale bar
10 m
actual size of object
represents 10 m;
× 4900 (±200);
Do not award the first mark if incorrect equations are set up such as 4.9 cm =
10 m.
magnification =
microvilli increase the surface area for absorption / active transport;
mitochondria produce ATP for active transport;
2
2
[9]