Mammals have mass transport systems to move substances around the body.
Which feature of mammals, A to D, explains why they need mass transport systems?
A low metabolic rates
B large surface area to volume ratios
C short diffusion distances
D small surface area to volume ratios
[1]
Which of the biofluids, A to D, is not an extracellular fluid?
A cell sap
B lymph
C plasma
D urine
[1]
The photomicrograph shows part of a transverse section through a mammalian aorta.
Which of the rows, A to D, correctly identifies some of the tissues that would be found in the areas labelled X, Y and Z in the photomicrograph?
| X | Y | Z | |
| A | endothelium | collagen fibres and connective tissue | smooth muscle tissue |
| B | smooth muscle tissue | elastic tissue | endothelium |
| C | endothelium | smooth muscle tissue | collagen fibres and connective tissue |
| D | smooth muscle tissue | endothelium | elastic tissue |
[1]
Which of the options, A to D, is the site of initiation of action potentials that lead to the contraction of heart muscle?
A accelerator nerve
B Purkyne fibres
C sinoatrial node
D vagus nerve
[1]
The diagram shows a blood bag label with information about the stored blood product contained in
Which of the options, A to D, about this stored blood product is correct?
A Contains plasma and erythrocytes with no A or B glycoprotein antigens in the plasma membrane.
B Contains plasma with anti-A and anti-B antibodies and erythrocytes.
C Contains concentrated erythrocytes with A and B glycoprotein antigens in the plasma membrane.
D Contains concentrated erythrocytes with no A and B glycoprotein antigens in the plasma membrane.
[1]
The table shows the results from an analysis of some of the organic compounds found in a human urine sample.
| Concentration (g dm | –3) | ||||
| Carbon (C) | Nitrogen (N) | Oxygen (O) | Hydrogen (H) | Sulfur (S) | |
| Organic compounds | 5.15 | 7.46 | 4.78 | 1.24 | 0.13 |
Which of the molecules, A to D, would contain the sulfur shown in the analysis?
A amino acids
B nucleic acids
C pyruvate
D urea
[1]
A pregnant woman has been advised to increase her daily intake of protein by 15% to 53 g.
Which of the options, A to D, is her normal daily intake of protein?
A 28 g
B 8 g
C 46 g
D 38 g
[1]
Milk fat contains many different types of triglycerides. The molecules that make up these triglycerides can affect the flavour and nutritional properties of milk fat.
Which of the molecules, A to D, would not be found in a triglyceride?
[1]
A 45-year-old patient was admitted to hospital with a lung infection.
The patient was tested for tuberculosis (TB) using a Mantoux skin test. The Mantoux skin test is performed by injecting an extract from the TB pathogen under the skin.
After 48 hours, the patient had developed a large, red lump at the site of the test.
Which of the following statements is/are correct?
1: The patient’s blood contained antibodies against TB antigens.
2: The patient did not have immunity to TB.
3: The patient had an inflammatory response to live TB pathogens present in the extract.
A 1, 2 and 3 are correct
B only 1 and 2 are correct
C only 2 and 3 are correct
D only 1 is correct
[1]
Diphtheria is a bacterial disease of humans that can be treated by vaccination using an antitoxin. The antitoxin is a solution of antibodies specific to the antigens on the surface of the bacterium.
Which of the options, A to D, describes the type of immunity provided by the antitoxin?
A artificial active
B artificial passive
C natural passive
D natural active
[1]
Oils from the clove tree, Syzygium aromaticum, have been found to have antifungal properties and are a potential source of medicinal drugs.
The graph shows the results of a study into the effect of concentration of clove oil on the growth of fungi on cooked meat.
Which of the options, A to D, is the correctly calculated percentage decrease in growth of fungi as the concentration of clove oil increases from 0.02 to 0.04%?
A 71%
B 22%
C 78%
D 29%
[1]
Which of the options, A to D, explains why viruses are not destroyed by antibiotics?
A Viruses do not have DNA.
B Viruses do not have nuclei.
C Viruses do not have plasmids.
D Viruses do not have cell walls.
[1]
Which of the options, A to D, is formed by the fusion of a cell membrane around a microorganism?
A bleb
B phagosome
C vacuole
D virus
[1]
An investigation was carried out into the effect of concentration of a substance on its rate of uptake into cells.
The cells were placed in solutions of the substance at different concentrations and rate of uptake was measured.
Which of the options, A to D, is the mechanism being used by the cells to transport the substance across the cell membrane?
A active transport
B facilitated diffusion
C osmosis
D simple diffusion
[1]
Which of the eukaryotic cell membranes, A to D, is used to isolate enzymes that could cause cellular damage?
A lysosome membrane
B mitochondrial membrane
C nuclear membrane
D tonoplast
[1]
The structure and part of the classification of Chlamydomonas reinhardtii, a single-celled organism, is shown below.
Which of the following statements is/are correct?
1: C.reinhardtii would be classified in the Kingdom, Bacteria.
2: C.reinhardtii is a photosynthetic organism.
3: Chlamydomonadaceae is the family taxon for C.reinhardtii.
A 1, 2 and 3 are correct
B only 1 and 2 are correct
C only 2 and 3 are correct
D only 1 is correct
[1]
The cytochrome c oxidase gene is a good DNA barcode.
Which of the features, A to D, are needed for a good DNA barcode?
A low interspecific variation
B high intraspecific variation
C short sequences of DNA
D species specificity
[1]
A phylogenetic tree for five species is shown below.
distance scale = 0.5
The evolutionary distance between two species is calculated as the sum of the lengths of all the horizontal branches between the two species.
Which of the options, A to D, is the estimated evolutionary distance between species R and species T ?
A 8.0
B 4.0
C 2.0
D 16.0
[1]
Two heterozygous individuals with the genotype, HhRr, were crossed during an investigation of dihybrid inheritance.
Which of the options, A to D, shows the probability of offspring having the genotype, HHRR?
A 1 in 4
B 3 in 4
C 1 in 16
D 1 in 2
[1]
Somatic cell gene therapy has been used for treating people with mitochondrial myopathy, a disease of the muscles caused by damage to the mitochondria.
Which of the following statements is/are correct?
1: DNA sequences coding for the functional gene are placed into muscle cells.
2: Meiosis will ensure that all muscle cells receive a copy of the functional gene.
3: The functional gene will be passed on to the offspring of the treated individual.
A 1, 2 and 3 are correct
B only 1 and 2 are correct
C only 2 and 3 are correct
D only 1 is correct
[1]
Taq polymerase is an enzyme used during the polymerase chain reaction (PCR).
• At optimum temperature, Taq can replicate DNA at a rate of 150 nucleotides per second.
• The error rate of Taq has been measured at 1 in 9000 nucleotides.
Which of the options, A to D, is the estimated number of errors that could be produced by during 20 minutes of PCR at optimum temperature?
A 180
B 60
C 20
D 1200
[1]
Which of the options, A to D, about the onset of menopause and secretion of female hormones is correct?
A Secretion of follicle-stimulating hormone (FSH) increases.
B Secretion of luteinising hormone (LH) decreases.
C Secretion of oestrogen increases.
D Secretion of progesterone increases.
[1]
Which of the statements, A to D, about why respiration in animals and plants is dependent on photosynthesis is correct?
A Triose phosphate (TP) can be hydrolysed into glucose.
B Triose phosphate (TP) can form 6-carbon sugars.
C Triose phosphate (TP) and glycerate-3-phosphate (GP) can be joined to form sucrose.
D Triose phosphate (TP) can be converted into fatty acids.
[1]
Which of the structures, A to D, in the ruminant digestive system secretes hydrochloric acid and digestive enzymes?
A abomasum
B omasum
C reticulum
D rumen
[1]
[1]
Existing treatments for kidney failure include dialysis and transplant surgery. Therapeutic cloning involves growing kidney tissue from the patient’s stem cells and is another type of treatment which may be available in the future.
For which of the treatments, A to D, would the patient need to take immunosuppressant drugs?
A donation of a kidney from a living relative
B haemodialysis
C peritoneal dialysis
D therapeutic cloning
[1]
The kidney has several functions as an endocrine organ.
Which of the options, A to D, is not an endocrine function of the kidney?
A osmoregulation to control the reabsorption of water
B secretion of erythropoietin to increase production of red blood cells
C secretion of renin to catalyse the formation of angiotensin to increase blood pressure
D selective reabsorption of glucose to prevent it being lost during excretion
[1]
A group of students were investigating the rate of translocation in plants using aphids.
The diagram shows the apparatus used in their investigation.
10 cm 20 cm 30 cm 40 cm
The sap from each colony of aphids was analysed for the presence of radioactively labelled sugars.
Rate of translocation was calculated based on the time taken for the radioactively labelled sugars to be detected in each of the colonies positioned along the length of the stem.
• Diameter of the phloem tube was 2 mm
• Mean translocation rate calculated by the students was 0.5 cm3 hr–1
• Volume of a cylinder = 
r2l
In which of the aphid colonies, A to D, were radioactively labelled sugars first detected after 1.3 hours?
[1]
Which of the statements, A to D, describes vernalisation in flowering plants?
A Exposure to high temperatures for an extended time period to encourage flowering.
B Exposure to high temperatures for an extended time period to encourage germination.
C Exposure to low temperatures for an extended time period to encourage flowering.
D Exposure to low temperatures for an extended time period to encourage germination.
[1]
Hydrogen carbonate indicator was used to investigate gaseous exchange in plants by measuring the change in pH.
• The indicator ranges from yellow at pH 7.6 to purple at pH 9.2.
• The indicator is red in atmospheric air with normal carbon dioxide concentration.
Four test tubes containing 2 cm3 of hydrogen carbonate indicator and equal-sized leaves from the same plant were prepared as shown in the diagram below. The test tubes were then illuminated under the same light source for 8 hours.
tube 1
tube 2
tube 3 tube 4
| Test tube | 1 | 2 | 3 | 4 |
| Colour of indicator after 8 hours | yellow | red | purple | red |
Which of the statements, A to D, about the outcome of the investigation is correct?
A Both photosynthesis and respiration are taking place in all four test tubes.
B The rate of photosynthesis is greater than the rate of respiration in test tube 2.
C The rate of photosynthesis is greater than the rate of respiration in test tube 3.
D The rate of photosynthesis is equal to the rate of respiration in test tube 3.
[1]
Spermatogenesis in human males produces haploid gametes, called spermatozoa (sperm cells).
The structure of a mature human spermatozoan consists of three sections: a head, a midpiece and a tail.
For each of these sections, describe how its internal structure relates to the function of the spermatozoan.
[3]
During spermatogenesis, the chromatin in the nuclei of sperm cells undergoes a complex transition where histone is replaced by another protein, protamine, which binds to the DNA.
Protamine contains large quantities of the polar amino acid, arginine.
Suggest why having large quantities of arginine enables protamine to bind effectively to DNA molecules.
[2]
Substituting histone with protamine allows DNA to be more densely packaged.
Suggest one advantage of having densely packaged DNA in a sperm nucleus.
[1]
It has been found that protamine deficiency can lead to a severe disruption of spermatogenesis affecting male infertility.
An investigation was carried out into the effect of protamine deficiency on the production of healthy sperm cells.
Forty semen samples were collected from four groups of men as shown in the table.
| Group | Sperm count | Motility of sperm |
| 1 | normal | normal |
| 2 | low | normal |
| 3 | normal | low |
| 4 | low | low |
Microscope slides were prepared by fixing and staining a smear from each semen sample. The staining technique used distinguished between protamine deficient and normal sperm cells.
The researchers concluded that the ages of the men in the groups would not affect the validity of the results of this investigation.
Explain how the researchers could have justified this conclusion.
[2]
What is the role of Group 1 in this investigation?
[1]
The results of the investigation are shown in the graph.
Using the information from the table and the graph, what conclusions can be made about the results of the investigation?
[4]
* Female gametes, or ova, are produced during oogenesis.
Compare and contrast spermatogenesis and oogenesis in the production of gametes. Include reference to the role of hormones.
Additional answer space if required.
[6]
The photomicrograph below shows a section through the wall of a mammalian eye.
The tissues of the eye shown in the photomicrograph were stained using eosin, which binds to cytoplasmic proteins staining them pink, and haematoxylin, which stains cell nuclei dark blue.
Describe the advantages of this method of staining tissues for viewing under a microscope.
[2]
Outline the structure and function of the outer layer, labelled P, in the photomicrograph.
[2]
The layer labelled Q contains highly pigmented cells.
Name layer Q and state the importance of this layer to the functioning of the eye.
[2]
Four students were given copies of the photomicrograph and asked to measure the width of the retinal layer in the image using a mm ruler.
The students recorded their results in the table below.
Find the mean of the data and use it to calculate the actual width of the retinal layer.
[2]
Calculate the uncertainty in the mean value for this data.
Use the equation:
R = difference between maximum and minimum values
N = number of measurements taken
[2]
Bardet-Biedl syndrome (BBS) is a human genetic disorder. One of the main symptoms is child-onset loss of vision.
Abnormalities of cilia are known to be related to a wide range of disease symptoms including those commonly seen in BBS patients. It is now accepted that mutated BBS genes affect microtubules and the normal functioning of cilia.
In the early childhood of individuals with BBS, deterioration of cone cells in the retina occurs, leading to poor visual acuity and colour blindness.
Using your knowledge of the internal structure of photoreceptor cells, suggest why mutated BBS genes lead to deterioration of cone cells and poor visual acuity.
[2]
Explain how cone cells enable humans to distinguish colour.
[3]
Obesity, syndactyly, diabetes and kidney failure are other symptoms associated with BBS.
Suggest why BBS is described as a syndrome.
[1]
State the mechanism that prevents syndactyly occurring in healthy individuals.
[1]
The coronary artery supplies blood to the heart. If the coronary artery is blocked or damaged a heart attack may occur.
When a person is suspected of having a heart attack it is a medical emergency and the first step of the emergency procedure is to call for an ambulance.
State two other steps in the emergency procedure for a person who is suspected of having a heart attack.
Question 33(b) begins on page 26
[2]
Alcohol is a drug known to reduce the heart rate in humans. A group of students wanted to find out if alcohol had the same effect on the heart rate of the water flea, Daphnia magna
One of the students made the following notes about the investigation.
1. We put a sample of Daphnia on a depression slide containing deionised water (control).
2. We put the slide under a light microscope and recorded a live video of the Daphnia sample.
3. We replayed the video in slow motion and counted the number of heart beats in 20s for 12 different Daphnia.
4. We then calculated the heart rate and recorded our data as the number of beats per minute (bpm).
5. We put a sample of Daphnia on a slide containing 2.5% alcohol and waited two minutes.
6. After two minutes we measured the heart rate using the same method as before.
7. We also repeated the investigation with 5% alcohol but decided that we could not repeat our investigation using this concentration, so we chose to use 2.5% alcohol.
8. We concluded that alcohol lowers the heart rate of Daphnia but the difference is not significant.
Give one reason why note 5, but not note 1, mentions that the students ‘waited for two minutes’.
[1]
Suggest one reason why the students decided that they could not repeat the investigation using 5% alcohol concentration.
[1]
The results of the students’ investigation are shown in Table 33.1.
Use the results in Table 33.1 to carry out a Student’s paired t-test for these data.
Use the equations:
[3]
The table of critical values for 5% significance level is shown in Table 33.2.
Using Table 33.2 and your answer to c(i), comment on the conclusion made by the students in note 8: ‘We concluded that alcohol lowers the heart rate of Daphnia but the difference is not significant’.
[2]
Tonle Sap Lake in Cambodia is one of the world’s most productive and biodiverse freshwater ecosystems.
The human population of the Tonle Sap Lake live on floating villages that rise and fall with the water levels and depend on the traditional ways of living from rice farming, fishing and extracting forest resources.
The location map shows the Tonle Sap Lake with some of the human activities that take place.
* Using the information, evaluate the possible impact of human activities on the ecosystem of
the Tonle Sap Lake.
[6]
Additional answer space if required.
A team of ecologists recorded the number of animal species living in four different habitats provided by one region of the Tonle Sap Lake.
Their data are shown in the table below.
| Habitat | Number of different animal species |
| Deep water | 17 |
| Abandoned rice fields | 12 |
| Floodplain shrubland and forest | 92 |
| Rice fields | 4 |
Suggest reasons for differences in the number of animal species in these habitats.
[2]
State how the team of ecologists could calculate the biodiversity in each of these habitats and what additional data would be needed for the calculation.
[2]
Cambodia is thought to have the largest wild population of the Siamese crocodile, Crocodylus siamensis.
C.siamensis is a critically endangered species that is now virtually extinct in the wild in most other countries of Southeast Asia.
Studies of genetic diversity amongst the Cambodian population of C.siamensis in protected areas have provided some evidence that there was a recent genetic bottleneck event in the Tonle Sap Lake area.
Using this example, explain what is meant by the term, genetic bottleneck.
[3]
Give one possible cause for the genetic bottleneck event that affected C.siamensis.
[1]
Crocodile farms have been established on the Tonle Sap Lake to develop captive-breeding programmes for C.siamensis.
Genetic analysis data of C.siamensis populations from two different crocodile farms is shown in the table below.
| Population from Population from crocodile farm 1 crocodile farm 2 | |
| Number of individuals in the population | 45 15 |
| Number of gene loci studied | 35 40 |
| Number of monomorphic genes | 28 26 |
Using the data, calculate the percentage of polymorphic genes in the population of each crocodile farm.
Farm 1........ % Farm 2........ %
[2]
Using the table and your answers to (d)(i), comment on the suitability of each of these crocodile farms for developing a captive-breeding programme for C.siamensis.
[2]
Nucleic acids are required for the synthesis of proteins.
For each of the nucleic acids below, describe its role in protein synthesis.
Messenger RNA (mRNA)
[1]
Transfer RNA (tRNA)
[1]
DNA is the nucleic acid that provides the genetic information required for protein synthesis. This information is known as the genetic code.
Complete the passage below about the nature of the genetic code using the most appropriate word(s).
The sequence of bases in one strand of DNA provides the genetic code for making proteins.
Sections of DNA that code for specific polypeptides are known as........
A sequence of........ nucleotide bases is required to form a DNA codon
that codes for an amino acid. However, the genetic code is........, which
means that there is more than one codon for each amino acid. Each DNA codon is read
separately which means that there is no........ of bases in the sequence
during transcription.
[4]
Avidin is a glycoprotein found in the whites of bird and reptile eggs. It has been investigated as an alternative insecticide for crop plants such as wheat.
In one study, researchers produced transgenic wheat plants containing the avidin gene. The expression of this gene was found to offer some protection against the wheat weevil, Sitophilus granarius.
Outline a method that the researchers could have used to produce transgenic wheat plants.
[3]
Avidin acts as an insecticide by preventing wheat weevils from obtaining biotin in their diet. Biotin is an essential cofactor required by insects.
Suggest how avidin prevents insects from obtaining biotin.
[1]
Suggest why lack of biotin leads to the death of wheat weevils.
[2]
The resting potential of most neurones is maintained at about –65 mV.
Complete the table by deciding whether each of the statements about maintaining the resting potential of a neurone is true (T) or false (F).
[2]
The graph shows the changes in potential across a neurone membrane during an action potential.
Explain the feedback mechanism that causes the voltage to rise between points X and Y.
[3]
The paper as printed
Spotted a mistake on this page?Report a problem
