Download Which ratio limits the size of cells? A. The rate of metabolism to mass

Which ratio limits the size of cells?
A.
The rate of metabolism to mass
B.
The surface area to volume
C.
The mass to volume
D.
The surface area to mass
Which statements are characteristics of diffusion through membranes?
I.
Polysaccharides can be transported.
II.
It can be facilitated by special channels.
III.
It is affected by concentration gradients.
A.
I and II only
B.
I and III only
C.
II and III only
D.
I, II and III
Which statement is characteristic of tumours?
A.
They occur only in certain animal cells.
B.
They result from controlled cell division in only some organs.
C.
They result from uncontrolled cell division and occur in any organ.
D.
They result from partially controlled transcription.
Identify the atoms and ions from the table below.
Atoms
Ions
A.
H+
Na+
OH–
Cl–
B.
Fe
K
CH3COO–
H2O
C.
Fe
H2O
Ca2+
N3 –
D.
Na
C
I–
NO3 –
Which compounds are both organic and found in living organisms?
Glucose
C6H12O6
Carbon Dioxide
CO2
Urea
OC(NH2)
Calcium Carbonate
CaCO3
A.
B.
C.
D.
Key:
= present
= absent
What is an active site?
A.
The part of an enzyme that binds only to the product molecules.
B.
The sequence of amino acids responsible for the catalytic activity of enzymes.
C.
The sequence of amino acids responsible for the structure of an enzyme.
D.
The specific area responsible for the activity of all proteins.
hat is responsible for the conservation of the base sequence during DNA replication?
A.
DNA polymerase working on one strand at the same time.
B.
Unpaired bases always attracting their complementary nucleotides.
C.
DNA helicase and polymerase are complementary.
D.
Both strands are identical to each other.
Which graph shows the effect of increasing carbon dioxide concentration (CO2) on the rate
of photosynthesis?
A.
B.
C.
D.
(Total 1 mark)
What are the components of a eukaryotic chromosome?
A.
One DNA molecule and one large protein
B.
Many DNA molecules and many proteins
C.
One DNA molecule and many proteins
D.
Many DNA molecules and one large protein
What is a karyotype?
A.
Maternal and paternal autosomes arranged in pairs.
B.
Chromosomes arranged in pairs according to the number of their genes.
C.
Chromosomes arranged in pairs according to their size and shape.
D.
Chromosomes arranged in pairs according to their size.
What is the cause of sickle cell anemia?
A.
Errors in the translation of mRNA
B.
A base substitution mutation in DNA
C.
A transcription error that replaces A with U
D.
A mutation that leads to glutamic acid instead of valine
What is the relationship between Mendel’s law of segregation and meiosis?
A.
Only one of a pair of alleles appears in a gamete.
B.
The separation of “paternal” and “maternal” chromosomes shows no pattern.
C.
Gametes contain all dominant or all recessive alleles.
D.
Variation only results from two divisions.
What are the possible applications of DNA profiling?
I.
Solving paternity suits
II.
Aiding certain criminal investigations
III.
Identifying people who died last century
A.
I only
B.
I and II only
C.
II and III only
D.
I, II and III
What is natural selection?
A.
The mechanism that increases the chance of certain individuals reproducing.
B.
The mechanism that leads to increasing variation within a population.
C.
The cumulative change in the heritable characteristics of a population.
D.
The mechanism that explains why populations produce more offspring than the
environment can support.
Why is most food digested?
A.
Digestive enzymes require a variety of substrates.
B.
It ensures that the diet is balanced.
C.
Most ingested food molecules are large.
D.
To prevent disorders of the intestine.
he diagram below shows the human heart. Which parts contain the most oxygenated blood?
A.
P and T
B.
Q, R and S
C.
T, U, V and W
D.
T, U, R and S
What is a pathogen?
A.
A virus that causes a disease.
B.
Any organism or virus that causes a disease.
C.
A disease caused by bacteria or viruses.
D.
Any organism transmitted from humans to humans.
hat are responsible for the lowering of blood glucose levels?
I.
-cells in the pancreas
II.
Insulin molecules
III.
-cells in the pancreas
A.
II only
B.
I and II only
C.
II and III only
D.
I, II and III
Which fluid is sampled to try to detect chromosomal abnormalities in a fetus?
A.
Placental
B.
Umbilical
C.
Amniotic
D.
Spinal
Magellanic penguins (Spheniscus magellanicus) live and breed near the coast of Argentina.
However, their colonies are a long way from the open sea where they hunt for fish.
They cannot fly so have to swim to the feeding grounds. A study investigated how the
water currents due to high and low tides affected their journey to and from their
colonies. The results are shown below.
70
Current from
colony
Current to
colony
Current from
colony
60
50
Penguins / number
40
30
20
10
0
06:00
Morning
12:00
18:00
22:00
Evening
Time of day / hour
Key:
departing from colony
arriving at colony
[Source: R. P. Wilson, “Magellanic Penguins Spheniscus magellanicus commuting through San Julian Bay;
do current trends induce tidal tactics?”, Journal of Avian Biology (Oct 30 2003), vol. 32, issue 1, pp. 83-89.
Copyright © 2003. Reprinted with permission of Blackwell Publishing Ltd.]
(a)
(i)
Identify the number of penguins departing from the colony at 06:00 hours.
.......................................................................................................................
...
(1)
(ii)
Identify the time of day when most penguins arrive at the colony.
.......................................................................................................................
...
(1)
(b)
Describe the pattern of movement of penguins departing from the colony
between 06:00 hours and 22:00 hours.
.................................................................................................................................
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...
.................................................................................................................................
...
(2)
(c)
Suggest why there is little movement in either direction between 14:00 hours
and 16:00 hours.
.................................................................................................................................
...
.................................................................................................................................
...
(2)
The study also investigated the range of swim speed for one penguin when out hunting
in the open sea.
4.0
3.5
3.0
2.5
Swim speed / ms-1 2.0
1.5
1.0
0.5
0.0
06:00
11:00
16:00
Time of day / hour
[Source: R. P. Wilson, “Magellanic Penguins Spheniscus magellanicus commuting through San Julian Bay; do current
trends induce tidal tactics?”, Journal of Avian Biology (Oct 30 2003), vol. 32, issue 1, pp. 83-89. Copyright © 2003.
Reprinted with permission of Blackwell Publishing Ltd.]
(d)
Calculate the greatest difference in swim speed during the study.
.................................................................................................................................
...
.................................................................................................................................
...
(1)
(e)
Suggest two reasons for the changes in swim speed of the penguin during the
period of time of the study.
.................................................................................................................................
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...
(2)
The diagram below shows part of the coastline.
point Y
Land
Open sea
walking distance 175 m
point X
[Source: R. P. Wilson, “Magellanic Penguins Spheniscus magellanicus commuting through San Julian Bay; do current
trends induce tidal tactics?”, Journal of Avian Biology (Oct 30 2003), vol. 32, issue 1, pp. 83-89. Copyright © 2003.
Reprinted with permission of Blackwell Publishing Ltd.]
(f)
A penguin uses 88 joules of energy to walk one metre. Calculate the energy used
to walk from point X to point Y.
.................................................................................................................................
...
.................................................................................................................................
...
(1)
(g)
The penguin uses more energy swimming. Suggest one reason why most
penguins actually swim rather than walk from point X to point Y.
.................................................................................................................................
...
.................................................................................................................................
...
(1)
(h)
Explain why penguins have many mitochondria in the muscles used for
swimming.
.................................................................................................................................
...
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...
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...
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(2)
(Total 13 marks)
(a)
Explain how photosynthesis can be measured both directly and indirectly.
.................................................................................................................................
...
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...
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...
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...
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...
.................................................................................................................................
...
(3)
(b)
Outline two uses of absorbed carbohydrates in humans.
.................................................................................................................................
...
.................................................................................................................................
...
(2)
(c)
The diagram below represents an energy pyramid and four trophic levels.
IV
III
II
100 000 kJ m–2 yr–1
I
[Source: adapted from www.bio.miami.edu/dana/160/pyramid.gif]
(i)
Identify the trophic level of the organisms indicated below.
I.
..................................................................................................
.............
IV.
..................................................................................................
.............
(2)
(ii)
Calculate the approximate amount of energy in kilojoules transferred in
m–2 yr–1 from trophic level I to trophic level II.
.....................................................................................................................
kJ
(1)
(Total 8 marks)
a)
Draw and label a simplified structure of a nucleotide.
(2)
A genetic cross was made between pure-breeding snapdragon plants with red flowers
and pure-breeding snapdragon plants with white flowers. The cross produced F1
offspring that had only pink flowers. When the F1 plants were self-pollinated, the
resulting F2 generation had some red, some white and some pink flowers.
(b)
(i)
Identify the relationship between the red and white alleles for flower
colour.
.......................................................................................................................
...
(1)
(ii)
Deduce the genotype of the F1 plants.
.......................................................................................................................
...
(1)
(iii)
Construct a Punnett grid to show the cross between two F1 plants.
(2)
(iv)
Deduce the proportion of the different phenotypes of the F2 offspring.
.......................................................................................................................
...
.......................................................................................................................
...
(1)
(c)
Discuss two advantages of genetic screening.
.................................................................................................................................
...
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...
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...
(2)
(Total 9 marks)
Up to two additional marks are available for the construction of your answers.
(2)
(a)
Draw and label a diagram of the carbon cycle.
(5)
(b)
Outline the mechanism of inhalation in human lungs.
(5)
(c)
a)
Discuss the causes and effects of the greenhouse effect and ways to control it.
Draw and label a generalized prokaryotic cell as seen under the electron microscope.
(4)
(b)
Outline the process of meiosis.
(6)
(c)
a)
Explain the role of the following hormones in the menstrual cycle: estrogen,
progesterone, follicle stimulating hormone (FSH) and luteinizing hormone (LH).
Draw and label a diagram to illustrate the fluid mosaic model of biological membranes.
(5)
(b)
Using a table, compare aerobic and anaerobic respiration in a eukaryotic cell.
(5)
(c)
(a)
Explain the process of translation.
Outline how impulses are transmitted between neurons.
.................................................................................................................................
...
.................................................................................................................................
...
.................................................................................................................................
...
(2)
(b)
Explain the role of the nervous system in the voluntary contraction of the biceps
muscle.
.................................................................................................................................
...
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...
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he cyanobacterium (Calothrix elenkenii) is cultivated as a source of photosynthetic pigments
for use in research and industry. The chart below shows the quantity of two of the
pigments produced when exposed to a day of continuous dark, a day of 16 hours light
and 8 hours dark and a day of continuous light. This was repeated in both aerobic and
anaerobic conditions.
Key:
Dark
Chlorophyll
β-Carotene
Aerobic
Light – Dark
Light
Dark
Anaerobic
Light – Dark
Light
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5 4.0
4.5 5.0
5.5 6.0
Amount of Pigment / μg cm–3
[Source: Reprinted from Journal of Plant Physiology, Vol 161, Parsanna et al., “Modulation of pigment…” pages 1125–
1132,
 copyright (2002), with permission from Elsevier.]
(a)
Identify the light conditions that cause most chlorophyll to be made when the
cyanobacterium is cultivated anaerobically.
.................................................................................................................................
...
(1)
(b)
Calculate the percentage increase in chlorophyll grown anaerobically in the
light, compared with anaerobically in the dark.
.................................................................................................................................
...
(1)
(c)
Compare pigment production in different aerobic conditions.
.................................................................................................................................
...
.................................................................................................................................
...
.................................................................................................................................
...
(2)
(d)
Discuss why having more than one photosynthetic pigment is an advantage to
cyanobacterium.
.................................................................................................................................
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...
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...
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...
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(3)
(Total 7 marks)
(a)
State the net gain of ATP molecules during glycolysis of one glucose molecule.
.................................................................................................................................
...
(1)
(b)
State where in the mitochondrion the enzymes of the Krebs cycle are found.
.................................................................................................................................
...
(1)
(c)
Compare the process of chemiosmosis in both respiration and photosynthesis.
.................................................................................................................................
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(3)
(Total 5 marks)
he phylogeny below shows how and when vertebrates could have evolved. The lines show
when each lineage arose, split and in some cases became extinct.
[Source: http://evolution.Berkeley.edud/evosite/evo101/IIEAAddingtime.html
UC Museum of Paleontology’s Understanding Evolution (http://evolution.berkeley.edu).]
(a)
Identify how many years ago mammals split from birds and reptiles.
.................................................................................................................................
...
(1)
(b)
State the evidence which allows scientists to know that Placoderms existed.
.................................................................................................................................
...
.................................................................................................................................
...
(1)
(c)
Birds and mammals are warm blooded. Discuss the hypothesis that some
dinosaurs may have been warm blooded, using the phylogeny diagram opposite.
.................................................................................................................................
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...
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...
.................................................................................................................................
...
(3)
(d)
Outline how the geographical distribution of mammals has affected their
evolution.
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(2)
(Total 7 marks)
o determine whether bird song is innate or learned, songs of birds raised naturally were
compared with the songs of those raised in isolation. Two species, the Swamp Sparrow
(Melospiza georgiana) and the Song Sparrow (Melospiza melodia), were studied. The
number of different songs the birds sang, the average number of syllables in the notes,
the average length of the songs and the total number of notes were recorded.
12
18
16
14
12
Number of 10
8
syllables
6
4
2
0
10
8
Number
of different
songs
6
4
2
0
Normal
Isolated
3.0
50
2.5
40
2.0
Isolated
Normal
Isolated
Number of 30
notes per
20
song
Song
1.5
length / s
1.0
10
0.5
0.0
0
Normal
Key:
Normal
Swamp Sparrow
Isolated
Song Sparrow
[Source: Peter Marler, Anais da Academia Brasilereira de Ciências, (2004), 76 (2), pages 189–200
Adapted from Peter Marler, An Acad Bra Cienc, (2004), 76 (2), pages 189-200]
(a)
Calculate the difference in the number of notes per song between the normal and
isolated Swamp Sparrows.
.................................................................................................................................
...
(1)
(b)
Compare the song length of both species of sparrow.
.................................................................................................................................
...
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...
.................................................................................................................................
...
(2)
(c)
Define the term innate behaviour.
.................................................................................................................................
...
.................................................................................................................................
...
(1)
(d)
Discuss whether the results for the Song Sparrow support the hypothesis that
bird song is innate.
.................................................................................................................................
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...
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...
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(3)
(Total 7 marks)
(a)
State a function of the
(i)
hypothalamus;
.......................................................................................................................
...
(1)
(ii)
cerebellum.
.......................................................................................................................
...
(1)
(b)
Deduce, with a reason, the type of sensory receptor in the pupil reflex.
.................................................................................................................................
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...
onservationists noticed that the number of red squirrels (Sciurus vulgaris) in Wales was
declining, and the number of a newly introduced species, the North American grey
squirrel (Sciurus carolinensis), was increasing. In 1998, a project was started to reduce
the number of grey squirrels in 244 hectares of woodland in Wales. The graph below
shows the number of grey squirrels in 1998 and the number of red squirrels in 1999,
2000 and 2002. The data was collected at eight different sites (A–H).
1.2
1.1
1.0
0.9
0.8
0.7
Squirrel density/ 0.6
number per hectare 0.5
0.4
0.3
0.2
0.1
0.0
Key:
Grey 1998
Red 1999
Red 2000
Red 2002
A
B
C
D
E
F
G
H
Site
[Source: Craig Shuttleworth, (2003), Biologist, 50, (5), page 231, © Institute of Biologists]
(a)
Identify the year in which the greatest number of red squirrels was found in site
E.
.................................................................................................................................
...
(1)
(b)
State the number of sites that had a greater density of red squirrels in 2002
compared with the density of grey squirrels in 1998.
.................................................................................................................................
...
(1)
(c)
Discuss the hypothesis that decreasing the density of grey squirrels after 1999
led to an increase in the density of red squirrels in the following years.
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(3)
(d)
Outline the relationship between grey squirrels and red squirrels assuming that
they occupy the same niche.
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(3)
(Total 8 marks)
(a)
A pine forest has a net production of 42 kJ m–2 year–1. Respiration is 100 kJ m–2 year–
1
. Calculate the gross production.
.................................................................................................................................
...
(1)
(b)
State two difficulties of classifying organisms into trophic levels.
.................................................................................................................................
...
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...
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...
(2)
(c)
Explain how living organisms may change the abiotic environment during
ecological succession.
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(a)
(i)
(b)
(c)
(d)
(e)
48 (1)
1
(ii)
1
22:00 hours (evening) / 10 pm (units required)
greatest number leaving in early morning / 6:00 hours / 6 am;
reduces during midday / early afternoon / general decline from 6:00-16:00
hours / 6 am-4 pm;
increases slightly in evening / after 18:00 hours / 6 pm / 18:00-20:00
hours / 6 pm-10 pm;
2 max
(strongest) current to colony (so difficult to leave);
current brings in food;
long way to feeding grounds / long time feeding;
all / many out at sea hunting;
penguins resting;
2 max
(3.75ms1  1.0) = 2.75(0.50) ms−1 (units required)
slow / uniform (with some peaks) when looking for prey / fish;
(faster when) chasing / catching prey / fish;
(slow in) moments of rest;
(faster when) escaping predators;
(f)
15 400 joules / J / 15.4 kilojoules / kJ (units required)
(g)
can escape faster from predators in sea;
avoid human activity on land;
body more adapted to swimming / less adapted to walking;
1
2 max
1
Accept any valid adaptation looking for concept not
necessarily term.
temperature on land could be more extreme;
may feed while swimming;
1 max
Do not accept "faster to swim" unless qualified with
valid reason.
(h)
mitochondria provide ATP (from aerobic respiration);
(swimming) muscles require a lot of energy;
2
[13]
(a)
directly:
by production of oxygen / measuring the volume / number of bubbles
of gas produced;
by measuring the uptake of carbon dioxide;
changes in pH;
Do not accept “production of gas”.
indirectly:
by measuring the increase in biomass;
by measuring the production of glucose / starch / other suitable molecule;
3 max
Award [2 max] if only indirect measurements or direct
measurements are addressed.
Apply ECF if direct and indirect is confused for more
than one method.
(b)
(c)
(cell) respiration;
energy storage (as glycogen / fat) / energy source;
synthesis of glycoproteins / nucleic acids / some amino acids;
(i)
I:
(primary) producer / autotroph;
IV:
tertiary consumers / fourth level consumer;
2 max
2
Award [0] for “first” and “fourth”.
(ii)
10 000-20 000
1
[8]
(a)
diagram with ribose / deoxyribose / sugar, phosphate and base labelled and
connected;
correct linkage and spatial arrangement (with labels) eg phosphate linked
to sugar / deoxyribose and base to sugar / deoxyribose;
2
Any shapes are acceptable, emphasis is on correct
linkages.
(b)
(i)
codominance / incomplete / partial dominance
1
(ii)
CRCW / RW / other suitably defined symbols
1
(iii)
grid with gametes shown correctly (CR and CW / other);
all offspring genotypes shown;
2
1 red:2 pink:1 white / 25% red : 50% pink : 25% white;
1
(iv)
(c)
fewer children with genetic disease / can prevent genetic disease;
lower long-term health costs;
frequency of harmful alleles reduced;
allows early diagnosis / detection / confirmation of genetic disease;
treatment can start for genetic disease;
prepare (psychologically) parents for affected children;
can predict (probability of) genetic disease;
2 max
(a)
Award [1] for any of the following clearly drawn and correctly
labelled.
plants taking in CO2 (making carbohydrates) in photosynthesis;
animals eating plants;
animals / plants giving off CO2 by (cell) respiration;
decomposers / micro-organisms giving off CO2 by (cell) respiration;
fossilization of plant / animal parts / store carbon as fossil fuels;
factories / cars giving off CO2 through combustion of fossil fuels;
(dead) plants / animals to decomposers / saprotrophs;
(b)
inhalation means air entering;
external intercostal muscles contract;
diaphragm contracts / flattens / moves downwards;
thorax volume increases;
creates pressure difference / lower pressure in thorax / lungs / correct
reference to Boyles Law;
air enters lungs / inhales air by nose and mouth;
5 max
5 max
Accept any of the above points if clearly explained in a
labelled diagram.
(c)
causes: [2 max]
increased CO2 levels (from combustion of fossil fuels by cars / transport);
increased methane levels (from intensified animal farming / rice
(paddy / padi) fields);
increased CFCs levels (from sprays / industrial processes);
increased burning of forests / urbanization;
reduced use of N-fertilizers ( NO3 etc);
effects: [3 max]
higher levels of greenhouse gases increase the retention of heat reflected
from earth;
cause increased temperatures of atmosphere / global warming;
increase water evaporation / droughts / crop losses;
increase melting of polar ice / glaciers / release of trapped methane;
increased levels of sea / possible flooding of coastal areas;
changing weather patterns / climatic extremes;
controls: [3 max]
international measures to reduce combustion of fossil fuels (eg Kyoto
convention);
reduce use of cars / combustion motors / smaller cars / drive less / lower
speed limits / mass transit;
reduce energy consumption / use low energy light bulbs / use better
insulation in houses / increase use of electric cars;
increased protection / restoration of ecosystems / reforestation;
alternative energy sources (eg wind, solar, waves, nuclear);
eat local food;
feasible suggestion to increase photosynthesis / reduce CO2 (eg
spreading of nutrients in ocean to induce algae growth);
(Plus up to [2] for quality)
8 max
(a)
Award [1] for any of the following clearly drawn and correctly labelled.
Award [2 max] if two or more eukaryotic structures are given and if a nucleus
is included award [0].
cell wall / capsule / slime wall / layer;
plasma / cell membrane;
mesosome,
cytoplasm;
ribosomes;
nucleoid / naked DNA;
flagella;
pili;
plasmid;
size stated 1 to 10 μm;
4 max
(b)
two cell divisions / reduction-division / diploid to haploid / meiosis I
and meiosis II;
produce four (haploid) cells;
for production of sex cells / gametes / spores;
daughter cells are different from parent cells;
homologous chromosomes / two chromatids pair up;
line-up on equator;
(spindle fibres) pull homologous chromosomes to opposite poles;
two haploid cells are formed;
second division / like mitosis, separates chromatids to opposite poles;
6 max
Accept any of the above points if clearly explained in a
labelled diagram.
(c)
FSH stimulates (in first few / five days) follicle development (in ovary);
(FSH stimulates) follicles to secrete estrogen, (positive feedback);
low levels of estrogen initially inhibit FSH (and LH) secretion;
rapid increase in estrogen stimulates FSH / LH production, (positive
feedback);
estrogen also starts to repair / thicken endometrium / uterine lining;
LH stimulates ovulation;
LH causes follicle to produce less estrogen (negative feedback) / more
progesterone (positive feedback);
LH stimulates follicle to become corpus luteum;
corpus luteum secretes (more estrogen and) large level of progesterone
(positive feedback);
estrogen and / or progesterone stimulate thickening of endometrium /
uterus lining;
estrogen and / or progesterone inhibit FSH and LH secretion (by
negative feedback);
estrogen and / or progesterone levels fall after day 21-24 if no embryo
/ fertilization;
lower concentrations of estrogen and / or progesterone allow
disintegration of endometrium / menstruation occurs;
FSH secretion begins a new cycle;
Award [6 max] if only three hormones are explained.
8 max
(a)
Award [1] for any of the following clearly drawn and correctly labelled.
phospholipids (bilayer);
hydrophilic heads and hydrophobic tails;
intrinsic / integral proteins / protein channels;
glycoproteins / receptor proteins / glycolipids on outside;
cholesterol embedded in membrane;
extrinsic / peripheral proteins;
thickness size 10 nm (0.1 μm);
(b)
5 max
Award [1] for each correct row, up to [5 max].
Aerobic respiration
Anaerobic respiration
occurs in mitochondria
occurs in cytoplasm;
requires O2
occurs without O2;
both produce pyruvate from glucose (glycolysis);
uses fatty acids / lipids / amino
acids
doesn’t use fatty acids;
(Krebs cycle) produces CO2 and
H2O
(fermentation) produces ethanol / CO2
(in yeast);
(Krebs cycle) produces CO2 and
H2O
(fermentation) produces lactate in
animals (humans);
NADH produced in both;
large amount of ATP (36 per
glucose
molecule) produced
small amount of ATP (2 per glucose
molecule) produced;
5 max
(c)
messenger / mRNA attaches to ribosome (small unit);
many ribosome / polyribosomes bind to same mRNA;
carries codons / triplet of bases each coding for one amino acid;
transfer / tRNA each have specific anticodon;
triplet of bases for specific amino acid;
tRNA carries specific amino acid;
tRNA binds to ribosomes;
to corresponding triplet base / codon;
a second tRNA binds to next codon;
two amino acids bind together;
in a peptide linkage;
first tRNA detaches;
ribosome moves along mRNA;
another tRNA binds to next codon;
continues until polypeptide / protein formed to stop codon;
stop codon has no corresponding tRNA / amino acid / causes release
of polypeptide;
8 max
(Plus up to [2] for quality)
[20]
(a)
transmission occurs across a synapse;
neurotransmitter released / moves across the synapse;
influx of calcium ions;
neurotransmitter destroyed;
initiates transmission of impulse in second neuron;
(b)
(a)
impulse is initiated in the motor area of the cerebral cortex;
impulse travels from CNS to effector;
impulse carried in the motor neurons;
motor end plates of the neurons form synapse with muscle fibre;
stimulate contraction of muscle fibres / actin and myosin in biceps;
propioreceptors detect how stretched the muscle is;
feedback to the brain;
light dark
(b)
(c)
(d)
2 max
3 max
1
 1.00

100   200%

 0.5

1
dark has least of both pigments;
light has most  -carotene;
light-dark has most chlorophyll;
most total pigment in light;
light  dark is the only condition where more chlorophyll is made than
 -carotene;
2 max
pigments absorb light for photosynthesis / absorption spectrum;
more light absorbed more photosynthesis / action spectrum;
different pigments absorb different wavelengths of light;
can photosynthesize in different environmental conditions;
3 max
[7]
(a)
2
1
(b)
matrix (fluid)
(c)
Award [1] for each row, up to [3 max].
Respiration
1
Photosynthesis
both make ATP;
both involve electron transport;
protons move against a concentration gradient in both;
both require ATP synthetase;
occurs in mitochondrion
occurs in chloroplasts / thylakoids;
uses energy from oxidation
uses energy from light;
has NADH for electron
production
has water for electron production;
3 max
(a)
350 (10) million years (units required)
1
(b)
fossil evidence
1
(c)
dinosaurs are most recent reptiles to be separated from birds;
some dinosaurs may have actually been birds;
separation from birds may have come after warm blood evolved / common
ancestor;
some may have been warm blooded, others not;
two lines show that different dinosaurs evolved at different times;
3 max
all came from a common ancestor (less than 100 million years ago);
continents divided isolating some;
these evolved independently;
first the ancestors of monotremes were isolated, then marsupials and
placental mammals divided;
Australia separated and marsupials found there / other examples;
2 max
(d)
[7]
)
25 (1)
(b)
1
Song Sparrow song always longer than Swamp Sparrow;
isolation increases Song Sparrow song length but decreases Swamp
Sparrow song length;
2
Answers may be numerical.
(c)
(d)
(a)
(i)
(b)
a behaviour that occurs in all members of a species / behaviour determined
genetically / inherited / stereotyped behaviour / not learnt / instinctive
innate characteristics would be the same (or nearly the same) in normal
and isolated;
notes per song / number of songs very different so probably not innate;
number of syllables / song length similar / not so different so possibly
innate;
hypothesis not supported for all song characteristics;
1
3 max
osmoregulation / thermoregulation / hormone production
1
(ii)
1
coordination of movement / balance / posture
photoreceptor;
receptor stimulated by light;
2
[4]
(a)
2002 1
(b)
6/ABEFGH
(c)
hypothesis seems to be supported;
in most / five sites the red squirrel density has increased since 1999;
some sites decreased in density from 2000 to 2002;
may be other factors controlling squirrel density;
however there is no information about red squirrels in 1998 / more data
is required starting with same density of grey squirrels in 1998 and
different densities of red squirrels;
3 max
(principle of) competitive exclusion;
competition occurs between them;
most successful of the two increases in numbers;
displaces the other from the population;
3 max
(d)
1
[8]
(a)
(GP = NP + R = 42 + 100) = 142 kJ m−2 yr−1 (units required)
(b)
(c)
1
organisms can occupy several different trophic levels;
food sources may change / different diets at different times of the year;
feeding habits can vary through an organism’s life cycle;
2 max
roots break down rocks to form soil particles;
roots prevent soil erosion by binding action of roots / erosion is
increased due to
roots / burrowing / grazing animals;
plants decompose returning minerals / humus / organic matter to soil;
plants reduce wind;
plants produce shade;
lichens / mosses trap organic matter;
soil structure improves as organic content rises / increasing water
retention / aeration;
increase oxygenation of water due to photosynthesis / decrease
oxygenation of water due to decay;
light intensity decreases due to leaf canopy;
3 max
[6]