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Biotechnology — Free MYP5 Biology Practice Questions
1QuestionCRISPR-Cas9 Gene Editing TechnologyConcept Practice
2 marks~3 minCriterion B
Scientists use CRISPR-Cas9 to introduce a gene conferring antibiotic resistance into one group of bacteria; a second group receives no gene edit. Both groups are then exposed to the same antibiotic under identical incubation conditions, and bacterial survival is recorded.
a
State the independent variable and the dependent variable in this experiment. [1]
b
Identify one controlled variable and explain why it must be kept constant to ensure the results are valid. [1]
Solutions
2QuestionCRISPR-Cas9 Gene Editing TechnologyConcept Practice
2 marks~3 minCriterion A
The diagram shows the CRISPR-Cas9 system. Component A is the Cas9 protein, Component B is the guide RNA (gRNA), and Component C is the target DNA containing the PAM sequence.
a
State the role of the guide RNA (Component B) in the CRISPR-Cas9 system. [1]
b
Explain how the PAM sequence (part of Component C) and the Cas9 protein (Component A) work together to edit the target DNA. [1]
Solutions
3QuestionTherapeutic Cloning and Stem CellsConcept Practice
4 marks~6 minCriterion C
The diagram below shows a blastocyst, an early stage embryo used in therapeutic cloning.
a
Label the inner cell mass and trophoblast on the diagram.
b
Explain in your own words, using clear biological terminology, why cells from the inner cell mass are specifically used in therapeutic cloning rather than cells from the trophoblast.
Solutions
4QuestionCloning Efficiency and LimitationsConcept Practice
2 marks~3 minCriterion A
The diagram below shows a somatic cell from a female mammal prepared for somatic cell nuclear transfer (SCNT). Structure X is labelled on the diagram.
a
Identify structure X. [1]
b
Explain why structure X, rather than any other part of the cell, is transferred during SCNT. [1]
Solutions
5QuestionEnvironmental Ethics of GM OrganismsConcept Practice
2 marks~3 minCriterion A
The diagram below shows a genetically modified bacterium used in the commercial production of human insulin. A rod-shaped prokaryotic cell is visible, containing a large circular chromosome and a smaller circular structure labelled X. A highlighted segment within X represents an inserted human gene.
a
Identify the organism shown in the diagram. [1]
b
Describe the role of structure X in enabling the bacterium to produce human insulin. [1]
Solutions
6QuestionEthical Issues in Genetic EngineeringConcept Practice
2 marks~3 minCriterion A
The diagram below shows a bacterial cell used in genetic engineering.
a
Identify the small circular DNA structure highlighted in the diagram. [1]
b
Explain how this structure is used to introduce a human gene into a bacterial host cell. [1]
Solutions
7QuestionGenetic Data Ownership and PrivacyConcept Practice
2 marks~3 minCriterion D
Direct-to-consumer (DTC) genetic testing companies, such as 23andMe, collect and store vast quantities of genetic data from customers. This data is increasingly used beyond individual ancestry or health reports, raising important scientific and societal questions.
a
Identify and explain one real-world application of genetic data collected by DTC companies. [1]
b
Identify and explain one ethical issue arising from the way DTC companies use or share this genetic data. [1]
Solutions
8QuestionData Privacy and Risks in Genomic ResearchConcept Practice
3 marks~5 minCriterion A
A survey asked participants in three countries whether they were concerned about data privacy in genomic research. The results are shown below.
Country (percentage concerned): USA (72%), UK (58%), Japan (44%)
Country (percentage concerned): USA (72%), UK (58%), Japan (44%)
a
Describe the trend in data privacy concern across the three countries. [1]
b
Explain one biological reason why genomic data is considered more sensitive than other types of medical data. [2]
Solutions
9QuestionData Privacy and Risks in Genomic ResearchConcept Practice
2 marks~3 minCriterion A
During a genomics study, a buccal (cheek) swab is taken from a volunteer. The extracted cells are examined under a light microscope. A diagram of one cheek cell is provided, with a large, membrane-bound, centrally located organelle labelled X.
a
Identify the organelle labelled X. [1]
b
Explain why the DNA found in organelle X is described as "genomic" DNA, rather than the DNA found elsewhere in the cell. [1]
Solutions
10QuestionApplications in Tissue EngineeringConcept Practice
2 marks~3 minCriterion A
The diagram below shows a 3D-printed tissue scaffold used in regenerative medicine. Cells are seeded onto the scaffold surface; one cell is shown with its internal structures visible. Structure X is labelled inside the cell, surrounded by an extracellular matrix mesh.
a
Identify structure X. [1]
b
Explain how structure X enables the seeded cells to contribute to the formation of functional tissue on the scaffold. [1]
Solutions
11QuestionCRISPR-Cas9 Gene Editing TechnologyAssessment Practice
3 marks~5 minCriterion A
When CRISPR-Cas9 creates a double-strand break, the cell can repair it using either Non-Homologous End Joining (NHEJ) or Homology-Directed Repair (HDR). The graph below shows how the frequency of each pathway changes as the distance from the Cas9 cut site increases from 0 to 100 base pairs.
Explain the trend in DNA repair pathway choice as the distance from the Cas9 cut site increases. In your answer:
Explain the trend in DNA repair pathway choice as the distance from the Cas9 cut site increases. In your answer:
a
Describe the trend shown for both NHEJ and HDR frequencies. [1]
b
Explain why NHEJ frequency decreases as distance from the cut site increases. [1]
c
Explain why HDR frequency increases as distance from the cut site increases. [1]
Solutions
12QuestionGenetically Modified Crops and Agricultural ApplicationsAssessment Practice
6 marks~9 minCriterion A
A research team inserted a T-DNA cassette containing three pest-resistance genes — , , and — into the maize genome. Each gene is flanked by a constitutive promoter and a terminator sequence. The cassette is arranged: LB — promoter1--terminator1 — promoter2--terminator2 — promoter3--terminator3 — RB.
RT-PCR measured mRNA transcript levels in GM maize and its non-GM parent:
Gene: / /
GM maize (relative mRNA): 2.8 / 0.1 / 3.5
Non-GM parent (relative mRNA): 0.0 / 0.0 / 0.0
RT-PCR measured mRNA transcript levels in GM maize and its non-GM parent:
Gene: / /
GM maize (relative mRNA): 2.8 / 0.1 / 3.5
Non-GM parent (relative mRNA): 0.0 / 0.0 / 0.0
a
Deduce which transgenes are actively expressed in the GM maize, using the data to support your answer. [2]
b
Explain the roles of the promoter and terminator sequences in the expression of the inserted genes. [2]
c
Analyse why shows very low mRNA levels despite being present in the T-DNA cassette and regulated by a constitutive promoter. [2]
Solutions
13QuestionCRISPR-Cas9 Gene Editing TechnologyAssessment Practice
6 marks~9 minCriterion D
A research team is testing a guide RNA designed to target the gene using CRISPR-Cas9 technology as a potential HIV therapy. The experiment measured cleavage rates at three guide RNA concentrations.
| Guide RNA concentration (nM) | 10 | 50 | 250 |
|---|---|---|---|
| On-target cleavage rate (%) | 45 | 78 | 85 |
| Off-target cleavage rate (%) | 2 | 15 | 40 |
a
State the roles of the Cas9 nuclease and the guide RNA in the CRISPR-Cas9 system. [2]
b
Analyse the relationship between guide RNA concentration and both cleavage rates shown in the data. [2]
c
Justify whether this guide RNA is suitable for therapeutic use, using evidence from the data and cause-and-effect reasoning. [2]
Solutions
14QuestionCRISPR-Cas9 Gene Editing TechnologyAssessment Practice
4 marks~6 minCriterion D
A couple with a family history of Huntington's disease is considering CRISPR-Cas9 editing of the disease-causing mutation in their embryos before implantation. Huntington's disease is caused by a dominant allele producing a toxic protein that destroys neurons, leading to progressive and fatal neurological decline.
a
Explain how CRISPR-Cas9 technology could be used to edit the Huntington's disease mutation in an embryo. [1]
b
Discuss the ethical implications of using CRISPR-Cas9 for human germline editing in this context, including both potential benefits and risks. [2]
c
Evaluate the broader societal and ecological impacts of making heritable genetic modifications in human embryos. [1]
Solutions
15QuestionCRISPR-Cas9 Gene Editing TechnologyAssessment Practice
5 marks~8 minCriterion C
A researcher uses CRISPR-Cas9 to target the LMNA gene in human cells across two experiments.
Experiment A: Cas9 + guide RNA only (no donor template). After 48 hours: 85% of cells show a frameshift mutation in LMNA; 0% show a precise edit.
Experiment B: Cas9 + guide RNA + single-stranded donor DNA template carrying a specific base change. After 48 hours: 50% frameshift mutations; 30% precise edits; 20% unmodified.
Experiment A: Cas9 + guide RNA only (no donor template). After 48 hours: 85% of cells show a frameshift mutation in LMNA; 0% show a precise edit.
Experiment B: Cas9 + guide RNA + single-stranded donor DNA template carrying a specific base change. After 48 hours: 50% frameshift mutations; 30% precise edits; 20% unmodified.
a
State which DNA repair pathway produces frameshift mutations and explain why no precise edits occur in Experiment A. [2]
b
Using data from both experiments, explain how the presence of the donor template influences which repair pathway operates. [2]
c
Evaluate the hypothesis: "In these cells, NHEJ is always preferred over HDR when both repair templates are available." [1]
Solutions
16QuestionMedical Applications of Genetic ModificationAssessment Practice
6 marks~9 minCriterion C
A clinical trial tested three viral vectors for gene therapy in patients with severe combined immunodeficiency (SCID). The results are summarised below.
| Vector | Patients treated | Restored immune function | Adverse effects |
|---|---|---|---|
| Retrovirus | 40 | 32 | 8 |
| Adenovirus | 35 | 15 | 20 |
| CRISPR-Cas9 | 20 | 18 | 2 |
a
Calculate the success rate (restored function as a percentage of patients treated) for each vector. Deduce which vector shows the highest and which shows the lowest efficacy. [2]
b
Explain why the adenovirus vector shows the most anomalous pattern when adverse effects are compared with restored function, referring to a known biological characteristic of adenoviruses. [2]
c
Analyse one limitation of using this dataset to draw conclusions about the long-term safety of CRISPR-Cas9 gene therapy. [2]
Solutions
17QuestionReproductive Cloning TechniquesAssessment Practice
6 marks~9 minCriterion C
You are given two diagrams: Diagram A shows the process of natural sexual reproduction in mammals, and Diagram B shows the process of reproductive cloning using somatic cell nuclear transfer (SCNT).
Using these diagrams as evidence, explain in writing the key differences between the two methods in terms of:
Using these diagrams as evidence, explain in writing the key differences between the two methods in terms of:
1
The origin of the genetic material in the offspring.
2
The resulting genetic relationships between the offspring and its parents.
Your explanation should be clear, use appropriate biological terminology, and reference specific steps from the diagrams to support your points.
Your explanation should be clear, use appropriate biological terminology, and reference specific steps from the diagrams to support your points.
Solutions
18QuestionReproductive Cloning TechniquesAssessment Practice
4 marks~6 minCriterion B
A research team performed somatic cell nuclear transfer (SCNT) experiments to clone mice. They used donor cells from different tissue types and recorded the number of successful live births per 100 attempts:
Tissue type: Skin Muscle Mammary gland Liver Brain
Success rate: 12 18 25 8 3
Tissue type: Skin Muscle Mammary gland Liver Brain
Success rate: 12 18 25 8 3
a
Investigate the pattern in the success rates. Which tissue type appears most effective for reproductive cloning?
b
Generalize a rule: Based on this data, what characteristic of donor cells might explain the pattern in success rates?
c
Justify your rule using biological concepts about cell differentiation and gene expression.
Solutions
19QuestionReproductive Cloning TechniquesAssessment Practice
6 marks~9 minCriterion B
A research team performed reproductive cloning experiments using somatic cell nuclear transfer (SCNT) on mice. They recorded the success rates (percentage of attempts resulting in live births) using donor cells from different tissue types, each with varying degrees of differentiation. The data is presented below:
Tissue type: Skin Muscle Mammary gland Embryonic stem cells
Success rate: 12% 18% 25% 42%
Tissue type: Skin Muscle Mammary gland Embryonic stem cells
Success rate: 12% 18% 25% 42%
a
Investigate the pattern in the success rates. Describe the relationship between the differentiation state of the donor cells and cloning success.
b
Based on this pattern, formulate a general rule that predicts cloning success from donor cell type.
c
Justify your rule using biological reasoning about gene expression and cellular reprogramming in SCNT.
Solutions
20QuestionCloning Efficiency and LimitationsAssessment Practice
4 marks~6 minCriterion A
The diagram below shows two somatic cell nuclear transfer (SCNT) experiments. In Experiment 1, a donor nucleus from a 2-year-old sheep is transferred into an enucleated egg cell, producing a healthy blastocyst. In Experiment 2, a donor nucleus from a 12-year-old sheep is transferred into an enucleated egg cell, producing an abnormal blastocyst that degenerates.
a
Identify one cellular change that occurs in the nucleus of an aged donor cell that reduces cloning efficiency. [1]
b
Explain how this change impairs development of the cloned embryo. [1]
c
Explain how accumulated epigenetic modifications in an aged donor nucleus contribute to lower cloning efficiency, referring to both the reprogramming process and its effect on embryonic gene expression. [2]
Solutions
21QuestionCloning Efficiency and LimitationsAssessment Practice
2 marks~3 minCriterion D
A farmer plans to clone his entire dairy herd from a single prize-winning cow to maximise milk yield. All cloned individuals would be genetically identical.
Identify one ethical concern arising from cloning the entire herd. [1]
Explain why this concern should influence the farmer's decision about whether to proceed. [1]
Identify one ethical concern arising from cloning the entire herd. [1]
Explain why this concern should influence the farmer's decision about whether to proceed. [1]
Solutions
22QuestionCloning Efficiency and LimitationsAssessment Practice
6 marks~9 minCriterion D
A team of scientists proposes using cloning to revive the thylacine (Tasmanian tiger), extinct since 1936. Preserved thylacine DNA would be inserted into enucleated egg cells of the numbat, a related marsupial. The resulting embryo would be carried to term by a surrogate numbat. Scientists hope eventually to reintroduce thylacines into Tasmania, where the ecosystem has changed substantially over the past 90 years.
a
Identify and explain one ethical concern raised by this cloning proposal. [2]
b
Identify one ecological limitation of this approach to species restoration and explain how it would affect the long-term viability of a reintroduced thylacine population. [2]
c
Evaluate whether a population of cloned thylacines could genuinely constitute a restored species. [2]
Solutions
23QuestionEnvironmental Ethics of GM OrganismsAssessment Practice
7 marks~11 minCriterion B
A study monitored glyphosate-resistant weed populations across three GM crop management systems over ten years.
Year: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
Continuous GM crop (%): 5, 8, 12, 17, 23, 30, 38, 47, 57, 68
Rotation with non-GM crop (%): 2, 3, 5, 7, 10, 14, 19, 25, 32, 40
Organic buffer zones (%): 0, 0, 1, 1, 2, 3, 4, 5, 7, 9
Year: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
Continuous GM crop (%): 5, 8, 12, 17, 23, 30, 38, 47, 57, 68
Rotation with non-GM crop (%): 2, 3, 5, 7, 10, 14, 19, 25, 32, 40
Organic buffer zones (%): 0, 0, 1, 1, 2, 3, 4, 5, 7, 9
a
Analyse the trend in glyphosate resistance in the continuous GM crop system over the ten-year period, using data from the table to support your answer. [2]
b
Using the rate of change in the rotation system data, justify a prediction for the year in which resistance in that system will reach 50 percent. [3]
c
Evaluate the effectiveness of organic buffer zones compared with continuous GM cropping as a strategy for managing herbicide resistance, using evidence from the data and your understanding of selection pressure. [2]
Solutions
24QuestionEnvironmental Ethics of GM OrganismsAssessment Practice
4 marks~6 minCriterion D
The diagram shows a field of genetically modified (GM) herbicide-resistant corn adjacent to a population of wild teosinte, a close relative of corn. Arrows indicate pollen movement from the GM corn toward the wild teosinte.
a
Explain the biological process by which the herbicide-resistance gene may be transferred from the GM corn into the wild teosinte population. [2]
b
A farmer begins applying herbicide across both the GM corn field and the surrounding area. Analyse how the presence of the herbicide-resistance gene in the teosinte population could alter the competitive dynamics between teosinte and other wild plant species in the ecosystem. [2]
Solutions
25QuestionHuman Cloning and Moral ConcernsAssessment Practice
5 marks~8 minCriterion C
Study the diagram of the somatic cell nuclear transfer (SCNT) process and the two quotes below.
Diagram — SCNT process (5 steps):
Step 1: Nucleus removed from donor egg cell → enucleated egg cell.
Step 2: Nucleus extracted from a somatic cell (e.g. skin cell) of the person to be cloned.
Step 3: Somatic cell nucleus inserted into the enucleated egg cell → reconstructed cell.
Step 4: Reconstructed cell stimulated to divide → embryo forms.
Step 5: Embryo implanted into surrogate mother's uterus.
Quote A (for cloning): "Human cloning could allow infertile couples to have a genetically related child, fulfilling their desire for parenthood."
Quote B (against cloning): "Creating and then discarding embryos in cloning research treats human life as a mere tool, raising serious moral concerns."
Diagram — SCNT process (5 steps):
Step 1: Nucleus removed from donor egg cell → enucleated egg cell.
Step 2: Nucleus extracted from a somatic cell (e.g. skin cell) of the person to be cloned.
Step 3: Somatic cell nucleus inserted into the enucleated egg cell → reconstructed cell.
Step 4: Reconstructed cell stimulated to divide → embryo forms.
Step 5: Embryo implanted into surrogate mother's uterus.
Quote A (for cloning): "Human cloning could allow infertile couples to have a genetically related child, fulfilling their desire for parenthood."
Quote B (against cloning): "Creating and then discarding embryos in cloning research treats human life as a mere tool, raising serious moral concerns."
a
Explain the biological events occurring at each numbered step of the SCNT process, using appropriate biological terminology. [3]
b
Discuss how the ethical argument in each quote connects to a specific step of the SCNT process, identifying the step and explaining the biological basis of the connection. [2]
Solutions
26QuestionEthical Issues in Genetic EngineeringAssessment Practice
3 marks~5 minCriterion C
Genetically modified E. coli bacteria carry the human insulin gene under the control of an inducible promoter. When an inducer chemical is added to the bacterial culture, it activates this promoter, triggering transcription of the insulin gene. The graph below shows how the concentration of the inducer affects the level of insulin mRNA produced by the bacteria.
a
Describe the trend shown in the graph between inducer concentration and insulin mRNA level. [1]
b
Explain, at the molecular level, why increasing inducer concentration leads to greater insulin mRNA production. [1]
c
Evaluate the significance of this dose-dependent response for the controlled production of insulin as a therapeutic protein. [1]
Solutions
27QuestionEnvironmental Ethics of GM OrganismsAssessment Practice
6 marks~9 minCriterion A
A population of wild canola (Brassica rapa) grows near a field of genetically modified (GM) canola that produces Bt toxin. The GM canola carries a dominant resistance allele (R). Scientists tracked the frequency of allele R in the wild population over five generations at three isolation distances.
| Distance 100 m — Generation 1 | 0.02 | Gen 2: 0.08 | Gen 3: 0.15 | Gen 4: 0.25 | Gen 5: 0.38 |
|---|---|---|---|---|---|
| Distance 500 m — Generation 1 | 0.01 | Gen 2: 0.03 | Gen 3: 0.06 | Gen 4: 0.10 | Gen 5: 0.16 |
| Distance 1000 m — Generation 1 | 0.00 | Gen 2: 0.01 | Gen 3: 0.02 | Gen 4: 0.03 | Gen 5: 0.05 |
a
Deduce the trend in resistance allele frequency at 500 m over generations 1–5. [2]
b
Using the 500 m data, calculate the average increase in allele frequency per generation between generations 1 and 5, and use this value to estimate the allele frequency at generation 8. [2]
c
Evaluate whether the resistance allele frequency at 500 m will continue to rise indefinitely, using the concepts of gene flow, selection pressure, and allele frequency limits. [2]
Solutions
28QuestionHuman Genome Project OverviewAssessment Practice
3 marks~5 minCriterion B
The bar chart below shows the number of protein-coding genes and non-coding RNA genes identified across five human chromosome groups, ordered from largest (group 1–5) to smallest (group 21–22+X+Y).
| Protein-coding genes | 1200 | 900 | 700 | 500 | 300 |
|---|---|---|---|---|---|
| Non-coding RNA genes | 400 | 500 | 600 | 700 | 800 |
a
Calculate the ratio of protein-coding to non-coding RNA genes for chromosome group 1–5 and for chromosome group 21–22+X+Y. [1]
b
Describe the trend in this ratio as chromosome size decreases. [1]
c
Explain what this trend suggests about the contribution of smaller chromosomes to the functional complexity of the human genome. [1]
Solutions
29QuestionHuman Genome Project OverviewAssessment Practice
5 marks~8 minCriterion C
A family pedigree shows the following individuals across three generations. Filled symbols represent affected individuals; half-filled symbols represent carriers; empty symbols represent unaffected non-carriers.
Generation I: carrier father (I-1) × carrier mother (I-2)
Generation II: carrier son (II-1), carrier daughter (II-2), unaffected son (II-3), affected daughter (II-4)
Generation III: II-1 × unaffected mother (III-1) → affected son (III-2); II-2 × unaffected father (III-3) → unaffected son (III-4), affected daughter (III-5)
Generation I: carrier father (I-1) × carrier mother (I-2)
Generation II: carrier son (II-1), carrier daughter (II-2), unaffected son (II-3), affected daughter (II-4)
Generation III: II-1 × unaffected mother (III-1) → affected son (III-2); II-2 × unaffected father (III-3) → unaffected son (III-4), affected daughter (III-5)
a
Deduce whether the condition is dominant or recessive, using one piece of evidence from Generation I and II. [1]
b
Justify why X-linked recessive inheritance can be ruled out, using evidence from both Generation II and Generation III. [2]
c
Analyse how the pedigree as a whole supports autosomal recessive inheritance as the most consistent explanation for the pattern observed. [2]
Solutions
30QuestionHuman Genome Project OverviewAssessment Practice
5 marks~8 minCriterion C
The Human Genome Project (HGP) used two sequencing strategies: BAC (bacterial artificial chromosome) clone-by-clone sequencing and whole-genome shotgun sequencing. The data below summarise genome coverage and gaps at three stages.
| Initial draft (2001) | BAC coverage 90% | shotgun coverage 85% | gaps remaining 150 000 |
|---|---|---|---|
| After gap closure (2003) | BAC coverage 99% | shotgun coverage 92% | gaps remaining 340 |
| Final reference (2004) | BAC coverage 99.999% | shotgun coverage 95% | gaps remaining 0 |
a
Identify the percentage-point difference in genome coverage between the two methods at the after-gap-closure stage. [1]
b
Explain why the BAC clone-by-clone method was better suited than shotgun sequencing for closing gaps in repetitive regions of the genome. [2]
c
Evaluate the hypothesis that BAC clone-by-clone sequencing was more effective than whole-genome shotgun sequencing for completing the human reference genome, using evidence from all three stages. [2]
Solutions
31QuestionData Privacy and Risks in Genomic ResearchAssessment Practice
2 marks~3 minCriterion D
Direct-to-consumer genomic testing companies, such as 23andMe, collect and store individuals' genetic data, including variants associated with disease risk. This data may be shared with third parties, including insurers, without the individual's full awareness.
a
Identify one ethical issue related to data privacy in genomic research and support your answer with a real-world example. [1]
b
Discuss a specific limitation of current legislation in addressing this ethical issue. [1]
Solutions
32QuestionGenetic Disease Identification through Genome MappingAssessment Practice
3 marks~5 minCriterion A
A bar graph shows relative CFTR gene expression in lung tissue for three genotypes. The x-axis shows genotype; the y-axis shows relative expression, normalised to 1.0 for wild-type.
Wild-type: 1.0
Heterozygous carrier: ≈ 0.5
Cystic fibrosis (homozygous recessive): ≈ 0.1
Wild-type: 1.0
Heterozygous carrier: ≈ 0.5
Cystic fibrosis (homozygous recessive): ≈ 0.1
a
Describe the trend in CFTR expression across the three genotypes shown in the graph. [1]
b
Explain how the number of mutated CFTR alleles accounts for the expression level observed in each genotype. [1]
c
Explain how the severely reduced CFTR expression in homozygous recessive individuals leads to the pulmonary symptoms of cystic fibrosis. [1]
Solutions
33QuestionData Privacy and Risks in Genomic ResearchAssessment Practice
5 marks~8 minCriterion D
A genomic research study collected DNA samples from 500 volunteers. All personal identifiers were removed and each sample was assigned a random code. The anonymised single nucleotide polymorphism (SNP) data were uploaded to a public database. A journalist later re-identified several participants by cross-referencing the SNP data with a genealogy website containing named family trees and shared genetic markers. One re-identified participant subsequently faced increased health insurance premiums after the insurer obtained this information.
a
Define single nucleotide polymorphisms (SNPs) and explain how a combination of SNPs can uniquely identify an individual. [1]
b
Explain how linkage disequilibrium and database cross-referencing together made re-identification of the anonymised participants possible. [2]
c
Evaluate the biological and ethical consequences of this data breach for both the affected participants and the future of genomic research. [2]
Solutions
34QuestionPrinciples of 3D BioprintingAssessment Practice
3 marks~5 minCriterion B
A scientist conducts five trials of 3D bioprinting, varying nozzle diameter and extrusion pressure. Cell viability after printing is recorded below.
| Trial | 1 | 2 | 3 | 4 | 5 |
|---|---|---|---|---|---|
| Nozzle diameter (µm) | 100 | 200 | 300 | 400 | 400 |
| Extrusion pressure (kPa) | 10 | 20 | 30 | 40 | 20 |
| Cell viability (%) | 65 | 75 | 82 | 88 | 87 |
a
Deduce the relationship between nozzle diameter and cell viability using trials 1–4. [1]
b
Predict the cell viability for a trial using a nozzle diameter of 250 µm and an extrusion pressure of 25 kPa, showing your reasoning. [1]
c
Evaluate the extent to which nozzle diameter alone can explain the cell viability outcomes across all five trials. [1]
Solutions
35QuestionApplications in Tissue EngineeringAssessment Practice
4 marks~6 minCriterion A
The graph below shows the percentage mass remaining over time for two hydrogel scaffolds used in 3D tissue printing: PLGA (a synthetic polymer) and collagen (a natural protein).
Graph description: X-axis: Time (days), 0 to 28. Y-axis: Percentage mass remaining, 0% to 100%. PLGA decreases gradually from 100% to approximately 60% at day 28. Collagen decreases steeply from 100% to approximately 20% at day 28.
Graph description: X-axis: Time (days), 0 to 28. Y-axis: Percentage mass remaining, 0% to 100%. PLGA decreases gradually from 100% to approximately 60% at day 28. Collagen decreases steeply from 100% to approximately 20% at day 28.
a
Describe the degradation trends shown by both scaffolds over the 28-day period, using appropriate biological terminology. [2]
b
Explain which scaffold would better support cell infiltration and new tissue formation in a tissue engineering application. Use specific evidence from the graph and correct scientific language in your answer. [2]
Solutions
36QuestionApplications in Tissue EngineeringAssessment Practice
2 marks~3 minCriterion D
Bioprinting uses a patient's own cells to construct replacement organs layer by layer, offering a potential solution to global transplant shortages. However, the technology remains experimental: long-term outcomes in human recipients are largely unknown, and production costs are currently very high.
Outline one ethical issue a hospital must consider when deciding whether to offer 3D-printed organ transplants to patients. [2]
Outline one ethical issue a hospital must consider when deciding whether to offer 3D-printed organ transplants to patients. [2]
Solutions
37QuestionPrinciples of 3D BioprintingAssessment Practice
3 marks~5 minCriterion C
The table below shows the percentage of viable cells after 7 days of culture on four hydrogel scaffold materials used in 3D bioprinting.
| Hydrogel material | Cell viability after 7 days (percent) |
|---|---|
| Alginate | 72 |
| Collagen | 91 |
| Gelatin methacryloyl (GelMA) | 85 |
| Fibrin | 88 |
a
Identify the hydrogel material that supports the highest cell viability. [1]
b
Explain one biological reason why this material produces a higher cell viability than Alginate. [1]
c
A researcher proposes replacing collagen with GelMA to reduce production costs. Evaluate this proposal using the data and your knowledge of scaffold properties. [1]
Solutions
38QuestionApplications in Tissue EngineeringAssessment Practice
6 marks~9 minCriterion D
Three biodegradable scaffold materials (A, B, C) were tested for cartilage repair over 8 weeks. The percentage of scaffold mass lost and the mass of new tissue formed were recorded every two weeks.
Material A mass loss (%): 5, 10, 15, 20 at weeks 2, 4, 6, 8
Material A tissue mass (g): 0.1, 0.2, 0.3, 0.4 at weeks 2, 4, 6, 8
Material B mass loss (%): 20, 40, 60, 80 at weeks 2, 4, 6, 8
Material B tissue mass (g): 0.4, 0.7, 0.9, 1.0 at weeks 2, 4, 6, 8
Material C mass loss (%): 10, 20, 30, 40 at weeks 2, 4, 6, 8
Material C tissue mass (g): 0.3, 0.6, 0.8, 0.9 at weeks 2, 4, 6, 8
Material A mass loss (%): 5, 10, 15, 20 at weeks 2, 4, 6, 8
Material A tissue mass (g): 0.1, 0.2, 0.3, 0.4 at weeks 2, 4, 6, 8
Material B mass loss (%): 20, 40, 60, 80 at weeks 2, 4, 6, 8
Material B tissue mass (g): 0.4, 0.7, 0.9, 1.0 at weeks 2, 4, 6, 8
Material C mass loss (%): 10, 20, 30, 40 at weeks 2, 4, 6, 8
Material C tissue mass (g): 0.3, 0.6, 0.8, 0.9 at weeks 2, 4, 6, 8
a
Describe the relationship between scaffold mass loss and tissue mass formed for each material over the 8-week period. [2]
b
Explain why a scaffold that degrades too quickly or too slowly would be unsuitable for cartilage repair. [2]
c
Evaluate which material would best support cartilage repair by Week 12, using extrapolated trends and the requirement that scaffold degradation and tissue formation must remain coordinated throughout repair. [2]
Solutions
39QuestionPrinciples of 3D BioprintingAssessment Practice
5 marks~8 minCriterion C
A research team tests three bioink formulations for 3D-printing liver tissue constructs. The bioinks differ in viscosity: A (low), B (medium), C (high). Identical constructs are printed and cell viability (percentage of living cells) is measured at Day 1 and Day 7.
| Day 1 viability | A = 92% | B = 90% | C = 88% |
|---|---|---|---|
| Day 7 viability | A = 45% | B = 78% | C = 82% |
a
State the change in cell viability for bioink A between Day 1 and Day 7. [1]
b
Explain why bioink A shows higher cell viability than bioink C at Day 1, but lower viability at Day 7. [2]
c
Evaluate the hypothesis: "Higher viscosity bioink provides better long-term cell survival in 3D bioprinted liver constructs." [2]
Solutions
40QuestionApplications in Tissue EngineeringAssessment Practice
4 marks~6 minCriterion A
A research team is developing a biodegradable polymer scaffold for cartilage repair. The scaffold contains interconnected pores of uniform diameter (300 µm) and is pre-loaded with transforming growth factor-beta (TGF-β), a growth factor that promotes chondrocyte differentiation. As the polymer degrades, TGF-β is released gradually into the surrounding tissue.
a
Explain how the interconnected pore structure of the scaffold supports cell attachment and survival. [2]
b
Analyse how the gradual release of TGF-β from the degrading scaffold promotes organised cartilage regeneration, rather than simply stimulating random cell proliferation. [2]
Solutions