Question 1
Gas exchange occurs in the respiratory system. The human respiratory system is located in the thorax.
(a) The diagram shows some of the structures in the human thorax.
(i) What is the name of the structure labelled X?
A alveolus
B bronchiole
C bronchus
D trachea
(ii) Which of these describes what happens when a person breathes in?
A diaphragm contracts and moves downwards
B diaphragm contracts and moves upwards
C diaphragm relaxes and moves downwards
D diaphragm relaxes and moves upwards
(b) The table shows the percentage of some of the gases in inhaled air and exhaled air.
(i) Explain the differences between the percentages of gases in inhaled air and in exhaled air.
(ii) Air in the alveoli has a composition of 14% oxygen and 7% carbon dioxide.
Suggest why the composition of air in the alveoli is different from exhaled air.
▶️Answer/Explanation
1(a)(i) The only correct answer is B (bronchiole)
A is incorrect as X is not an alveolus
C is incorrect as X is not a bronchus
D is incorrect as X is not the trachea
1 (a)(ii) The only correct answer is A (diaphragm contracts and moves downwards)
B is incorrect because the diaphragm does not move upwards
C is incorrect because the diaphragm contracts
D is incorrect because the diaphragm contracts
1 (b)(i) An explanation that makes reference to three of the following:
- inhaled air contains more oxygen (than exhaled air) / inhaled air contains less carbon dioxide than exhaled air / eq (1)
- oxygen has diffused into the blood / carbon dioxide has diffused out of the blood (1)
- oxygen is used by respiration / eq (1)
- carbon dioxide is produced by respiration / eq (1)
- nitrogen is not used / released (by respiration) / eq (1)
1 (b)(ii) An explanation that makes reference to two of the following:
- exhaled air is a mixture of inhaled air and alveolar air / eq (1)
- no gas exchange occurs in the trachea / bronchi / bronchioles / eq (1)
- gas exchange (only) occurs at the alveoli (1)
Question 2
Tobacco mosaic virus infects plant cells.
The photograph shows some of the virus particles.
(a) (i) Tobacco mosaic virus particles consist of a molecule of RNA surrounded by a coat.
Which substance is the coat made from?
A cellulose
B chitin
C protein
D starch
(ii) The virus particle labelled P has an actual length of 0.3μm.
Calculate the magnification of this virus particle.
[1mm = 1000μm]
magnification = × ……………………………………………………..
(b) The photograph shows the leaves of a plant infected by tobacco mosaic virus.
Plants cells infected with the virus stop making chloroplasts.
Explain why plants that are infected with the virus grow more slowly than uninfected plants.
▶️Answer/Explanation
2(a)(i) The only correct answer is C (protein)
A is incorrect because viruses do not contain cellulose
B is incorrect because viruses do not contain chitin
D is incorrect because viruses do not contain starch
2 (a)(ii)
- x 76, 700 or 77000 (3)
Allow range between 73 000 up to 80 000 (3 marks)
2 (b) An explanation that makes reference to three of the following:
- less / no light (energy) absorbed / taken in / eq (1)
- (less) photosynthesis (1)
- (less) glucose (1)
- (less) starch / cellulose / less energy (for growth) / less ATP made / less active transport / (less glucose so) less respiration / eq (1)
Question 3
The diagram shows part of a woodland food web.
(a) (i) Which organism is a primary consumer in this food web?
A aphid
B blackbird
C fox
D oak tree
(ii) Which of these describes the woodland community?
A all the abiotic and biotic factors in the area
B all the blackbirds in the area
C all the different species and the habitat
D all the different species in the area
(b) This is one food chain from the food web.
oak tree → mouse →fox
(i) A student counted 20 mice living around 4 oak trees. There were also 2 foxes in the area.
Draw a labelled pyramid of numbers for this food chain on the grid.
Your pyramid should be drawn to scale.
(ii) Photosynthesis results in 25000kJ of energy being transferred to the biomass of the oak trees each year.
Only 8% of this energy is transferred to the biomass of the 20 mice each year.
Calculate the mean amount of energy transferred to the biomass of one mouse each year.
(iii) Explain why only 8% of the energy stored in the biomass of the oak trees is used by the mice for growth.
▶️Answer/Explanation
3 (a)(i) The only correct answer is A (aphid)
B is incorrect because blackbirds are secondary / tertiary consumers
C is incorrect because foxes are secondary / tertiary / quaternary consumers
D is incorrect because oak trees are producers
3 (a)(ii) The only correct answer is D (all of the different species in the area)
A is incorrect because it describes an ecosystem
B is incorrect because it describes a population
C is incorrect because it describes an ecosystem
3 (b) (i) An answer that makes reference to the following:
- symmetrical pyramid with correct shape (1)
- pyramid labelled (1)
- pyramid bars drawn to scale (1)
3 (b)(ii) 100 (kJ) (2)
3 (b)(iii) An explanation that makes reference to three of the following:
- not all organisms are eaten / some parts not eaten / eq (1)
- energy is lost due to respiration / heat loss / movement / eq (1)
- some die / decompose / eq (1)
- some is not digested / absorbed / some is egested / some lost as faeces / eq (1)
- energy lost as excretion / urea / eq (1)
Question 4
Cow’s milk contains a mixture of nutrients, including protein, fat, sugar, vitamins, and minerals.
(a) (i) The main sugar in milk is a carbohydrate called lactose.
Which chemical elements are present in carbohydrates?
A carbon and hydrogen only
B carbon, hydrogen, and oxygen only
C carbon, hydrogen, and nitrogen only
D carbon, hydrogen, nitrogen, and oxygen
(ii) Describe how to test a sample of milk for protein.
(b) Some people drink a milk alternative produced from plants, such as soy and rice, instead of milk produced by animals.
The table shows nutritional information for different milk products.
(i) The recommended daily amount of calcium for a child is 1400mg.
Calculate the mass of cow’s milk that would contain 1400mg of calcium.
mass = …………………………………………………….. g
(ii) Discuss whether soy milk or rice milk is a suitable replacement for cow’s milk in the diet of children.
▶️Answer/Explanation
4 (a)(i) The only correct answer is B (carbon, hydrogen, and oxygen only)
A is incorrect because carbohydrates also contain oxygen
C is incorrect because carbohydrates do not contain nitrogen
D is incorrect because carbohydrates do not contain nitrogen
4 (a)(ii) A description that makes reference to two of:
- add biuret solution (1)
- lilac / purple / pink colour (1)
4(b)(i)
- 1254(.4) / 1250 / 1300 (g) (2)
4(b)(ii) An answer that makes reference to five of the following points:
- rice has less protein (than cow’s milk) (1)
- lack of protein / rice, could lead to less growth / repair / eq (1)
- soy / rice has less fat than cow’s milk / soy has more fat than rice / eq (1)
- soy / rice has less energy (than cow’s milk) / rice has more energy than soy / soy has less energy than rice / eq (1)
- soy has less carbohydrate (than cow’s milk) / rice has more carbohydrate than soy / rice has more carbohydrate (than cow’s milk) / eq (1)
- (less energy means) children may be less active / respire less / get tired easily / eq (1)
- rice has very little / less / not enough calcium (1)
- lack of calcium / rice, could lead to rickets / weak bones teeth / eq (1)
- (overall) soy is closer to cow’s milk compared with rice / soy is a better substitute than rice / eq (1)
Question 5
The photograph shows a red fire ant.
Fire ants are pests that damage crops.
Phorid flies can be used as a biological control of fire ants.
Scientists use this method to investigate the use of pesticides and biological control on populations of fire ants that live on plants in glasshouses.
• in one glasshouse, keep plants with no treatment
• in a second glasshouse, treat plants with pesticide
• in a third glasshouse, treat plants with pesticide and then immediately introduce phorid flies
• count the number of fire ants in each glasshouse at intervals for 24 months
The table shows the scientists’ results.
(a) Give a reason why the scientists include results from a glasshouse with no treatment in their investigation.
(b) Draw a line graph to show the changes in the number of fire ants with pesticide only and with both pesticide and phorid flies for the 24 months.
Join your points with straight lines.
(c) Describe the effect of using pesticide only on the number of fire ants for the 24 months.
(d) Discuss the effects of using pesticide only and of using both pesticide and phorid flies on the number of fire ants.
Use the data and your own biological knowledge in your answer.
▶️Answer/Explanation
5 (a) it is a control (experiment) / to compare the results / check that change is due to the treatments / eq (1)
5 (b) linear scales that use at least half grid (1)
- both axes labelled (as months and number of ants) (1)
- points plotted correctly (1)
- points joined with straight lines (1)
- key / lines labelled (1)
5 (c) A description that makes reference to two of the following:
- decrease and an increase (1)
- increases from 6 months (1)
5 (d) An answer that makes reference to five of the following:
- with no treatment red fire ants increase (1)
- both treatments / pesticide and pesticide + phorid flies reduce number of red fire ants (over first 6 months) / eq (1)
- when using pesticides (alone) ants increase (later) / when using phorid flies ants do not increase / level off / eq (1)
- when population is constant, reproduction rate equals death rate / predation / eq (1)
- using (pesticides and) phorid flies / biological control lasts longer / is a long-term solution / only needs to be done once / eq (1)
- phorid flies will breed / reproduce (for longer time) / eq (1)
- pesticides wear off / wash off / stop working / eq (1)
- fire ants mutate / eq (1)
- (fire ants) become resistant (to the pesticides) / eq (1)
- natural selection occurs / eq (1)
Question 6
The following passage is about chemical coordination in animals and plants.
Complete the passage by writing a suitable word in the blank space.
Animals and plants use chemicals to coordinate responses. In animals, some glands produce hormones which are transported in the ……………………………………………………………………………….. of the blood. A high glucose concentration in the blood stimulates the release of a hormone called ………………………………………………………………………………… from the ………………………………………………………………………………… . This causes an organ called the ………………………………………………………………………………… to remove glucose from the blood and store it as a substance called ………………………………………………………………………………… .
Plant shoots grow towards light. This response is
called ………………………………………………………………………………… . The movement of a chemical
called ………………………………………………………………………………… to the shaded side of the shoot causes the
shoot to grow towards the light.
▶️Answer/Explanation
- plasma (1)
- insulin (1)
- pancreas (1)
- liver / muscles (1)
- glycogen (1)
- (positive) phototropism (1)
- Auxin/ I.A.A (1)
Question 7
A species of grass has a diploid chromosome number of 12.
(a) Which row in the table shows the number of chromosomes in the nucleus of a pollen grain, and in the nucleus of a root cell, of this grass?
(b) The diagram shows a flower from the grass plant.
Explain two ways this flower is adapted for wind pollination.
(c) Scientists use this method to investigate self-pollination and cross-pollination in a species of grass plant.
• take pollen grains from the anther of a flower
• place some of the pollen grains on the stigma of the same flower
• after one day, count how many of the pollen grains grow a pollen tube
Repeat the method but place the pollen grains on the stigma of a flower of a different plant.
The table shows the scientists’ results.
(i) State the dependent variable in this investigation.
(ii) Explain how the results of the investigation show that this species of grass plant is able to survive in a changing environment.
Use the information in the table to support your answer.
(d) Grass plants can also be produced by asexual reproduction.
New plants are produced from the roots of a parent plant.
(i) State the name of the type of cell division used to produce new plants by asexual reproduction.
(ii) Describe why it is an advantage for commercial growers to produce plants by asexual reproduction.
▶️Answer/Explanation
7 (a) The only correct explanation is B (6 and 12)
A is incorrect because the root cell will not have 6 chromosomes
C is incorrect because the pollen grain will not have 12 chromosomes
D is incorrect because the pollen grain will not have 12 chromosomes
7 (b) An explanation that makes reference to four of the following:
(mark in pairs)
- anthers hang outside / long / hinged filament / eq (1)
- so blow pollen in the wind / eq (1)
- stigma is feathery / hairy / hangs out of flower / eq (1)
- to catch pollen / eq (1)
- petal is small / not coloured / no nectary in flower (1)
- as insects are not attracted to it / eq (1)
- pollen is light / dust like / produced in large quantities (1)
- so easily carried by wind (1)
7 (c)(i) percentage / % of tubes that grow / number of / how many grow /eq (1)
7(c)(ii) An explanation that makes reference to three of the following:
- fewer (pollen tubes) grow when self-pollinated / more (pollen tubes) grow when cross pollinated / eq (1)
- (cross pollination) produces (more) genetic variation / eq (1)
- so that) natural selection can occur / for natural selection to act on / eq (1)
- some plants will have (different) adaptations / will have an advantage / are more adaptable / can survive different weather / eq (1)
7 (d)(i) ⋅ mitosis (1)
7 (d)(ii) An answer that makes reference to two of the following:
- plants will be genetically identical / have same gene / eq (1)
- plants will have same characteristics / phenotype / eq (1)
- many are produced / quick / eq (1)
- can be produced at any time of year / eq (1)
Question 8
Reflexes are responses that protect the body and involve the central nervous system (CNS).
(a) (i) Give the name of one part of the CNS.
(ii) If an animal steps on a sharp object, a reflex arc occurs so that it picks up its foot to prevent further damage.
Describe how named neurones bring about a withdrawal reflex to protect the animal from damage.
(b) The photograph shows a breed of dog called a border collie.
Some border collies have a genetic condition called sensory neuropathy.
Border collies with sensory neuropathy may be injured as their reflexes do not work well.
Sensory neuropathy is caused by a recessive allele, n. The dominant allele for not having sensory neuropathy is N.
The diagram shows a family pedigree for some border collies.
(i) Sex determination in dogs is controlled in the same way as in humans.
Which combination of sex chromosomes is present in the body cells of a male dog?
A XX
B XY
C Y
D YY
(ii) How many individuals in this family have the genotype Nn?
A 2
B 4
C 5
D 6
(iii) Determine the probability that the next offspring produced by individuals P and Q is a male with sensory neuropathy.
Include a genetic diagram in your answer.
probability = ……………………………………………………..
(iv) Dog breeders use selective breeding to try to remove harmful alleles from dog breeds.
Explain how selective breeding could be used to remove the allele for sensory neuropathy from a population of border collies.
▶️Answer/Explanation
8 (a)(i) brain / named part of brain/ spinal cord/ eq (1)
8(a)(ii) A description that makes reference to four of the following points:
- receptor receives / senses / detects (object) / eq (1)
- impulse (1)
- (impulse moves along) sensory neurone to CNS / spinal cord / relay neurone (1)
- (chemical diffusion of) neurotransmitters across synapse (1)
- motor neurone to effector / muscle (1)
- (muscle) contracts (1)
8 (b)(i) The only correct answer is B (XY) A is
incorrect because XX is female
C is incorrect because males have one X chromosome
D is incorrect because males have one X chromosome
8 (b)(ii) The only correct answer is D (6)
A is incorrect because 6 dogs must be heterozygous
B is incorrect because 6 dogs must be heterozygous
C is incorrect because 6 dogs must be heterozygous
8 (b)(iii) An answer that makes reference to the following points:
- both parents identified as Nn and Nn (1)
- gametes as N or n (for both parents) (1)
- offspring identified as NN, Nn, Nn, nn (1)
- (probability determined as) 0.125 / 1/8 / 12.5 % (1)
8 (b)(iv) An explanation that makes reference to three of the following points:
- do a test cross to identify dogs that are NN / homozygous (dominant) / eq (1)
- breed using dogs with no family history of sensory neuropathy / eq (1)
- mate dogs that do not have sensory neuropathy / do not breed from dogs with sensory neuropathy / eq (1)
- only allow homozygous dominant dogs to breed / breed with homozygous dominant dogs (1)
- select / mate / breed from offspring that do not have sensory neuropathy / are homozygous dominant / eq (1)
- repeat over several generations / eq (1)
Question 9
The diagram shows the human blood circulation system.
(a) (i) What is the name of the blood vessel labelled Z?
(ii) Which labelled blood vessel contains blood with the lowest concentration of carbon dioxide?
A W
B X
C Y
D Z
(b) Give two differences in the structure of the blood vessel labelled V and the structure of the blood vessel labelled Y.
(c) High blood pressure and the presence of certain genes are risk factors for coronary heart disease.
(i) Give two other risk factors for coronary heart disease.
(ii) Scientists compared the relationship between blood pressure and the number of deaths from coronary heart disease in Northern Europe, Eastern Europe and Japan.
The graph shows their results.
A high blood pressure is considered to be above 130 arbitrary units.
Use the graph and your own knowledge to comment on the causes of death due to coronary heart disease in each region.
▶️Answer/Explanation
9 (a)(i) . hepatic portal vein (1)
9 (a)(ii) The only correct answer is B (X)
A is incorrect because W is the pulmonary artery
C is incorrect because Y is the aorta
D is incorrect because Z is the hepatic portal vein
9 (b) An answer that makes reference to two of the following points:
- (V / vein has) thin(ner) wall (1)
- (V / vein has) less / thin muscle (1)
- (V / vein has) fewer elastic fibres / less elastic (1)
- (V / vein has) valves (present) (1)
- (V / vein has) wide(r) lumen / space / hole / eq (1)
9 (c)(i) An answer that makes reference to two of the following points:
- obesity / eq (1)
- diabetes (1)
- high (saturated) fat diet / high cholesterol / eq (1)
- high salt diet / eq (1)
- low exercise / eq (1)
- smoking / alcohol (1)
- stress / eq (1)
- age (1)
9 (c)(ii) An answer that makes reference to four of the following points:
- increasing blood pressure increases deaths / eq (1)
- Northern / Eastern Europe have a steep / big increase (as blood pressure increases) / Japan has less / low increase / steady increase (as blood pressure increases) / eq (1)
- Japan has lowest number of deaths (at all blood pressures) / Northern / Eastern Europe has highest / Japan has lower death rate / eq (1)
- (Northern / Eastern) Europe has more deaths (compared with Japan) when blood pressure is healthy / below 130 / eq (1)
- decrease in number of deaths in Eastern Europe from 120 to 130 a.u. / at 130 / eq (1)
- Japan may have lower death rates due to genetics / heredity / eq (1)
- people in Japan may have better diet / healthy lifestyle / more exercise / less stress / less smoking / less obesity (so reduces deaths or heart disease) / eq
- no idea of sample sizes / no record of other factors / age / sex / lifestyle / diet / exercise / smoking / data / eq (1)
Question 10
A student investigates factors affecting the rate of photosynthesis.
(a) Complete the balanced chemical symbol equation for photosynthesis.
…………………………………………………….. + …………………………………………………….. → …………………………………………………….. + 6O2
(b) The diagram shows apparatus that can be used to measure the rate at which a piece of pond weed produces bubbles of oxygen.
The student uses this apparatus to investigate the effect of changing light intensity and carbon dioxide concentration on the rate of photosynthesis in pond weed.
This is the student’s method.
Step 1 fill the test tube with 5% sodium hydrogen carbonate solution
Step 2 place a piece of pond weed into the test tube
Step 3 place a lamp 5cm from the test tube
Step 4 count the number of bubbles produced by the pond weed in two minutes
Step 5 repeat steps 1 to 4 with the lamp at distances of 10cm, 15cm, 20cm, and 25cm
This method is repeated using 10% sodium hydrogen carbonate solution.
The table shows the results of the investigation.
The student used the same colour of light in the investigation.
(i) Describe how the student could control one other relevant, named abiotic factor.
(ii) Explain the effect of changing the distance of the lamp on the rate of photosynthesis of pond weed in both concentrations of carbon dioxide.
(iii) Describe one way the student could modify this method to obtain more accurate data.
(iv) Describe how the student could ensure that the results of the investigation are reliable.
▶️Answer/Explanation
10 (a)
- 6CO2 + 6H2O (1)
- C6H12O6 (1)
10 (b)(i) An answer that makes reference to two of the following points:
(mark in pairs)
- temperature (1)
- use a water bath / eq (1)
OR - pH (1)
- use a buffer (1)
10 (b)(ii) An explanation that makes reference to the following points:
- as distance (of lamp) increases, light (intensity) decreases / eq (1)
- decreasing light intensity / increasing distance (at either concentration), decreases (rate of) photosynthesis / number of bubbles / eq (1)
- as less energy (is absorbed) / eq (1)
- with 5% solution there is no change in bubble production (from 5 cm) up to 15 cm / rate levels off between 15 cm and 5 cm / eq (1)
- with 5% solution carbon dioxide is the limiting factor (between 5 cm and 15 cm) / carbon dioxide does not limit the rate of photosynthesis in the 10 % solution / eq (1)
- light is a limiting factor (at both concentrations) for distances at / over 15 cm (1)
10 (b)(iii) An answer that makes reference to the following points:
- (collect / measure) volume (1)
- using a measuring cylinder /syringe / burette / eq (1)
10 (b)(iv) A description that makes reference to two of the following points:
- repeat (1)
- calculate means / averages (1)
- identify / remove anomalies / check that results are concordant / eq (1)
Question 11
Biological washing powders contain protease enzymes to digest proteins in clothing stains.
Scientists have produced recombinant plasmids containing a gene for a protease enzyme that works at high temperatures. The plasmids have been inserted into bacteria so that the bacteria produce the protease enzyme.
(a) Describe how named enzymes are used to produce a recombinant plasmid containing a gene for a protease.
(b) Design an investigation to find the best temperature for removing protein stains by using washing powder that contains protease enzyme.
Include experimental details in your answer and write in full sentences.
▶️Answer/Explanation
11 (a) A description that makes reference to the following points:
- restriction enzymes cut out (protease) gene / cut plasmid / cut DNA (1)
- ligase joins / combine / glue (protease) gene plasmid / DNA (1)
11 (b) An answer that makes reference to the following points:
- C: range of at least three temperatures / use a wide range of temperatures (1)
- O: same concentration of enzyme / mass of washing powder / type of washing powder / type of enzyme / eq (1)
- R: repeats (1)
M1: measure area / size of stain / mass of stain / colour of stain / mass of protein / eq (1) - M2: stated time period (1)
- S1 same pH / water volume / washing movements / same type of material / clothing / size of material / eq (1)
- S2 same mass of protein / area of protein / type of protein stain / same blood / same named protein / eq (1)