VCE-BIO-U34 11.1 📋 – Practice Exam 8: Question Paper

Genetic carrier testing is used to identify individuals who:

Cystic fibrosis is caused by mutations in the CFTR gene and is inherited in which pattern?

Tay-Sachs disease, caused by mutations in the HEXA gene, is an autosomal recessive condition with a notably higher carrier frequency in which population, making targeted carrier screening programs particularly valuable?

Amniocentesis is a prenatal diagnostic procedure that involves:

Compared with amniocentesis, chorionic villus sampling (CVS):

Non-invasive prenatal testing (NIPT) works by:

Preimplantation genetic diagnosis (PGD) allows prospective parents undergoing IVF to:

Direct-to-consumer genetic testing services, such as 23andMe, typically analyse a customer’s DNA using:

A key scientific limitation of polygenic risk scores provided by direct-to-consumer genetic testing companies is that:

A major concern regarding genetic privacy raised by the growth of direct-to-consumer genetic testing is that:

Under Australia’s genetic testing moratorium (introduced by the Financial Services Council), life insurers are:

Unlike the United States, which has the Genetic Information Nondiscrimination Act (GINA) prohibiting genetic discrimination in employment and health insurance, Australia:

In the 2015 case D’Arcy v Myriad Genetics Inc, the High Court of Australia ruled that:

The reasoning behind the High Court’s decision in D’Arcy v Myriad Genetics centred on the idea that:

One practical consequence of the Myriad ruling for Australian patients was that:

In Australia, dealings with genetically modified organisms (GMOs), including research, field trials and commercial release, are regulated under the Gene Technology Act 2000 by the:

Food Standards Australia New Zealand (FSANZ) is responsible for:

Under the Australia New Zealand Food Standards Code, mandatory labelling of a food as ‘genetically modified’ is generally required when:

The concept of ‘substantial equivalence’, used in the safety assessment of GM foods, involves:

Synthetic biology is best described as a field that involves:

A CRISPR-based gene drive is designed to:

A key ecological and ethical concern raised about releasing gene drive organisms into the wild is that:

In 2018, scientist He Jiankui announced the creation of the first CRISPR-edited human babies (targeting the CCR5 gene). This was widely condemned by the international scientific community primarily because:

A key ethical distinction in gene editing is that, compared with somatic cell gene editing, germline gene editing:

Luxturna, an approved gene therapy for an inherited form of vision loss, works by:

In ex vivo gene therapy, compared with in vivo gene therapy:

The CRISPR-Cas9 gene editing system introduces targeted changes to DNA by:

A significant safety concern with current CRISPR-Cas9 technology is the possibility of:

Pharmacogenomics is the study of:

An example of a pharmacogenomic application in clinical practice is:

Genetic discrimination refers to:

Informed consent is considered particularly important before an individual undergoes predictive genetic testing (e.g. for a late-onset disease such as Huntington disease) because:

The primary role of a genetic counsellor is to:

In Australia, the newborn bloodspot screening (‘heel prick’) test is used to:

One ethical concern associated with population-wide genetic carrier screening programs is that:

Compared with a SNP microarray, whole genome sequencing:

A significant bioethical issue with some direct-to-consumer genetic testing companies is that:

Examples of genetically modified crops currently approved and grown commercially in Australia include:

The precautionary principle, as applied to biotechnology regulation, holds that:

When evaluating the ethical implications of a new genetic testing technology, bioethicists commonly apply four key principles: autonomy, beneficence, non-maleficence and justice. ‘Justice’ in this context primarily refers to:

Question 1: Carrier Testing and Inheritance

Question 1: Carrier Testing and Inheritance
Cystic fibrosis (CF) is an autosomal recessive disorder caused by mutations in the CFTR gene. Two unaffected parents, both known carriers of a CFTR mutation from a previous genetic carrier screening test, are planning to have children.
(i) Using a Punnett square approach (described in words), calculate the probability that their child will be affected by cystic fibrosis. (2 marks)
(ii) Explain why carrier testing is offered to prospective parents before conception, and describe one reproductive option available to a couple identified as both being carriers who wish to reduce the chance of having an affected child. (3 marks)

Question 2: Prenatal Testing Methods

Question 2: Prenatal Testing Methods (a)
A 38-year-old pregnant woman is offered a choice of prenatal testing options to assess the risk of her baby having a chromosomal condition such as Down syndrome (trisomy 21). Compare non-invasive prenatal testing (NIPT), chorionic villus sampling (CVS) and amniocentesis in terms of timing during pregnancy, the biological sample analysed, and associated risk of miscarriage.

Question 2: Prenatal Testing Methods

Question 2: Prenatal Testing Methods (b)
Explain why a positive NIPT result for trisomy 21 is generally followed up with a diagnostic test such as CVS or amniocentesis, rather than being treated as a final diagnosis.

Question 2: Prenatal Testing Methods

Question 2: Prenatal Testing Methods (c)
Discuss one ethical consideration a pregnant woman and her partner might need to weigh when deciding whether to undergo invasive diagnostic prenatal testing.

Question 3: Direct-to-Consumer Genetic Testing Case Study

Question 3: Direct-to-Consumer Genetic Testing Case Study (a)
A 32-year-old woman purchases a direct-to-consumer (DTC) genetic testing kit online. She provides a saliva sample, which is analysed using a SNP microarray. Her results report: (1) she has an ‘increased’ polygenic risk score for type 2 diabetes; (2) she is a carrier for a cystic fibrosis-associated CFTR mutation; and (3) 8% of her genetic ancestry is estimated to be from a region she did not expect. She later discovers that, as part of the company’s terms of service, her de-identified genetic data may be used in third-party pharmaceutical research. Explain the biological basis of the SNP microarray technology used to generate this woman’s results, and explain why this differs from whole genome sequencing.

Question 3: Direct-to-Consumer Genetic Testing Case Study

Question 3: Direct-to-Consumer Genetic Testing Case Study (b)
Explain why her ‘increased’ polygenic risk score for type 2 diabetes should not be interpreted as a certain prediction that she will develop the disease.

Question 3: Direct-to-Consumer Genetic Testing Case Study

Question 3: Direct-to-Consumer Genetic Testing Case Study (c)
Discuss the potential real-world implications of her carrier status result for (i) her own reproductive planning and (ii) her biological relatives, who did not personally consent to testing.

Question 3: Direct-to-Consumer Genetic Testing Case Study

Question 3: Direct-to-Consumer Genetic Testing Case Study (d)
Identify and explain one genetic privacy issue raised by this scenario.

Question 4: Genetic Privacy and the Australian Insurance Moratorium

Question 4: Genetic Privacy and the Australian Insurance Moratorium (a)
In Australia, the Financial Services Council introduced a moratorium restricting the use of predictive genetic test results by life insurance companies for policies below a certain value. Explain the purpose of this moratorium and describe one way it aims to balance the interests of insurers with the interests of individuals who undergo genetic testing.

Question 4: Genetic Privacy and the Australian Insurance Moratorium

Question 4: Genetic Privacy and the Australian Insurance Moratorium (b)
Discuss one potential limitation or criticism of relying on an industry moratorium (rather than binding legislation) to protect individuals from genetic discrimination.

Question 5: Gene Patents – D’Arcy v Myriad Genetics

Question 5: Gene Patents – D’Arcy v Myriad Genetics (a)
Myriad Genetics held patents over isolated BRCA1 and BRCA2 gene sequences (associated with hereditary breast and ovarian cancer) in several countries. In Australia, Yvonne D’Arcy challenged the validity of Myriad’s patent over an isolated BRCA1 gene sequence. In 2015, the High Court of Australia unanimously ruled in her favour. Explain the key legal/scientific argument that formed the basis of the High Court’s decision that the isolated BRCA1 sequence was not a patentable invention.

Question 5: Gene Patents – D’Arcy v Myriad Genetics

Question 5: Gene Patents – D’Arcy v Myriad Genetics (b)
Explain why the existence of a gene patent, prior to this ruling, could have restricted patients’ access to genetic testing and increased its cost.

Question 5: Gene Patents – D’Arcy v Myriad Genetics

Question 5: Gene Patents – D’Arcy v Myriad Genetics (c)
Evaluate one potential benefit and one potential drawback of allowing patents on isolated human gene sequences, from a biotechnology innovation perspective.

Question 6: GMO Food Regulation and Labelling

Question 6: GMO Food Regulation and Labelling (a)
In Australia, the approval and labelling of genetically modified (GM) food is governed by both the Office of the Gene Technology Regulator (OGTR) and Food Standards Australia New Zealand (FSANZ). Distinguish between the respective roles of the OGTR and FSANZ in the regulation of GM food products in Australia.

Question 6: GMO Food Regulation and Labelling

Question 6: GMO Food Regulation and Labelling (b)
A food company produces a highly refined vegetable oil from a genetically modified canola crop. The refining process removes essentially all detectable DNA and protein from the final oil product. Using your understanding of Australian GM food labelling requirements, explain whether this oil is likely to require GM labelling, and justify your answer.

Question 7: Gene Drives and Synthetic Biology

Question 7: Gene Drives and Synthetic Biology (a)
Scientists have proposed using a CRISPR-based gene drive to spread a gene causing infertility through wild populations of malaria-carrying mosquitoes, with the aim of suppressing mosquito populations and reducing the spread of malaria. Explain how a gene drive can spread a gene through a population much faster than would occur through normal Mendelian inheritance.

Question 7: Gene Drives and Synthetic Biology

Question 7: Gene Drives and Synthetic Biology (b)
Outline two ecological or ethical concerns that a regulatory body might consider before approving the release of gene drive mosquitoes into the wild.

Question 7: Gene Drives and Synthetic Biology

Question 7: Gene Drives and Synthetic Biology (c)
Explain why gene drive technology is often described as an application of synthetic biology.

Question 8: CRISPR Babies Case Study Ethics

Question 8: CRISPR Babies Case Study Ethics (a)
In 2018, He Jiankui used CRISPR-Cas9 to edit the CCR5 gene in human embryos, which were then implanted and resulted in the birth of twin girls, with the stated aim of making them resistant to HIV infection. This work was conducted with limited independent oversight and was widely condemned by the international scientific community. Explain two distinct ethical problems with He Jiankui’s experiment, referring to both the nature of the genetic modification and the process used.

Question 8: CRISPR Babies Case Study Ethics

Question 8: CRISPR Babies Case Study Ethics (b)
Explain why germline editing of human embryos raises different ethical considerations to somatic gene therapy carried out on a consenting adult patient with an existing disease.

Question 9: Pharmacogenomics

Question 9: Pharmacogenomics (a)
A patient is prescribed the anticoagulant drug warfarin following a diagnosis of atrial fibrillation. Before determining the correct dose, the patient’s doctor orders a pharmacogenomic test analysing variants in the CYP2C9 and VKORC1 genes. Explain how variation in the CYP2C9 and VKORC1 genes can influence an individual’s required dose of warfarin.

Question 9: Pharmacogenomics

Question 9: Pharmacogenomics (b)
Explain one benefit of using pharmacogenomic testing to guide drug prescribing, compared with a traditional ‘one dose fits all’ approach.

Question 10: Genetic Counselling and Population Screening Ethics

Question 10: Genetic Counselling and Population Screening Ethics (a)
A community-wide carrier screening program is proposed to test all prospective parents in a particular population for carrier status of several recessive genetic conditions common in that community, with genetic counselling offered to all participants regardless of result. Explain the role of a genetic counsellor in supporting individuals who receive a carrier-positive result through this program, and outline why non-directive counselling is considered important in this context.

Question 10: Genetic Counselling and Population Screening Ethics

Question 10: Genetic Counselling and Population Screening Ethics (b)
Discuss one potential social or psychological drawback of population-wide carrier screening programs that genetic counsellors and health authorities need to carefully manage.