VCE-BIO-U34 7.1 📋 – Practice Exam 4: Question Paper

A signal molecule that cannot cross the plasma membrane (e.g. a peptide hormone) must act via:

Cyclic AMP (cAMP) functions in cell signalling as:

Apoptosis differs from necrosis in that apoptosis is:

Which of the following is a steroid (lipid-soluble) hormone that can diffuse into cells and bind an intracellular receptor?

In signal transduction pathways, the general role of protein kinases is to:

In recombinant DNA technology, restriction enzymes (restriction endonucleases) are used to:

In gel electrophoresis, DNA fragments are separated according to:

Stem cells are characterised by their ability to:

Induced pluripotent stem cells (iPSCs) are produced by:

In DNA profiling, short tandem repeats (STRs) are useful markers because:

Gene therapy is a technique that involves:

A recombinant protein such as human insulin is typically produced by:

The release of oxytocin during labour, which stimulates uterine contractions that in turn stimulate further oxytocin release, is an example of:

Negative feedback in thermoregulation means that:

Transgenesis refers to:

The purpose of a vector (e.g. a plasmid) in recombinant DNA technology is to:

Which of the following is a potential benefit associated with genetically modified (GM) crops?

Bioethics, as applied to biotechnology, involves:

In CRISPR-Cas9 gene editing, the double-strand break created by the Cas9 enzyme is typically repaired by one of two cellular pathways:

Which of the following is a recognised risk associated with using viral vectors in gene therapy?

Which type of cell signalling involves a signal molecule acting on the very cell that secreted it?

Paracrine signalling is best described as:

Ligand-gated ion channel receptors respond to ligand binding by:

Receptor tyrosine kinases (RTKs), such as the insulin receptor, are activated when ligand binding causes:

Which second messenger is generated by the enzyme phospholipase C and functions to trigger the release of calcium ions from the endoplasmic reticulum?

In PCR (the polymerase chain reaction), the DNA polymerase commonly used is heat-stable because it is derived from:

The three repeating steps of a standard PCR cycle are, in order:

In CRISPR-Cas9 gene editing, the short single guide RNA (sgRNA) functions to:

A PAM (protospacer adjacent motif) sequence is required for CRISPR-Cas9 editing because:

Somatic cell nuclear transfer (SCNT), the technique used to produce Dolly the sheep, involves:

Reproductive cloning differs from therapeutic cloning in that reproductive cloning:

The 1975 Asilomar Conference is historically significant in the field of biotechnology because it:

In Australia, genetically modified organisms (GMOs) proposed for release into the environment are primarily regulated by:

The eugenics movement of the early-to-mid 20th century is widely condemned today primarily because it:

Golden Rice is a genetically modified crop that has been engineered to:

A key public concern raised in ethical debates about germline gene editing (editing embryos or gametes, as opposed to somatic cells) is that:

Western blotting is a laboratory technique used to:

ELISA (enzyme-linked immunosorbent assay) tests, used in various diagnostic settings, work by:

Pharmacogenomics is the study of:

A key biosafety consideration when a genetically modified organism is proposed for release into the environment is:

Describe a G-protein coupled receptor (GPCR) signalling pathway. Include the steps from signal molecule binding to cellular response.

Explain the intrinsic (mitochondrial) pathway of apoptosis.

Describe the steps involved in producing recombinant human insulin using E. coli.

Explain the principle behind DNA profiling (STR analysis) and describe two applications.

Discuss the ethical issues surrounding human embryonic stem cell research.

Compare CRISPR-Cas9 and traditional transgenic techniques for genetic modification. Include advantages of CRISPR.

Explain what homeostasis is, using body temperature regulation as an example of negative feedback.

Describe the role of monoclonal antibodies in medical diagnosis and treatment. Give one example of each use.

<strong>Extended Response 1: Signal Transduction and Cell Response (a)</strong><br>Compare the signalling pathways of lipid-soluble hormones (e.g. oestrogen) and water-soluble hormones (e.g. insulin). Include the receptor location, second messenger (if any) and cellular response.

<strong>Extended Response 1: Signal Transduction and Cell Response (b)</strong><br>Explain how signal amplification occurs in cell signalling cascades.

<strong>Extended Response 2: Biotechnology and Society (a)</strong><br>Describe the potential applications and ethical concerns associated with gene therapy for treating genetic diseases.

<strong>Extended Response 2: Biotechnology and Society (b)</strong><br>Evaluate the risks and benefits of genetically modified organisms (GMOs) in agriculture.

Extended Response 3: CRISPR Gene Editing Therapy for Sickle Cell Disease

Extended Response 3: CRISPR Gene Editing Therapy for Sickle Cell Disease (a)
Casgevy (exagamglogene autotemcel) is a CRISPR-Cas9-based gene-editing therapy approved in the United States and United Kingdom for sickle cell disease. Haematopoietic (blood) stem cells are collected from the patient’s own blood, and CRISPR-Cas9 is used ex vivo (outside the body) to edit a regulatory region (enhancer) of the BCL11A gene in these cells, before they are reinfused into the patient. Describe the molecular mechanism by which this editing reduces the symptoms of sickle cell disease, referring to the roles of BCL11A, fetal haemoglobin and adult (sickle) haemoglobin.

Extended Response 3: CRISPR Gene Editing Therapy for Sickle Cell Disease

Extended Response 3: CRISPR Gene Editing Therapy for Sickle Cell Disease (b)
Explain why this therapy is classified as somatic (ex vivo) gene therapy rather than germline gene therapy, and outline one key scientific or ethical distinction between these two approaches.

Extended Response 3: CRISPR Gene Editing Therapy for Sickle Cell Disease

Extended Response 3: CRISPR Gene Editing Therapy for Sickle Cell Disease (c)
In a hypothetical clinical trial, patients with severe sickle cell disease were followed for 12 months after receiving either the CRISPR-based therapy or standard care (blood transfusions and pain management). The table below shows the percentage of patients who were free of vaso-occlusive crises during this period.

Group | Number of patients | % free of vaso-occlusive crises at 12 months
CRISPR therapy | 30 | 90%
Standard care (control) | 30 | 20%

Describe the trend shown by this data, and identify one limitation of this hypothetical study design.

Extended Response 3: CRISPR Gene Editing Therapy for Sickle Cell Disease

Extended Response 3: CRISPR Gene Editing Therapy for Sickle Cell Disease (d)
Discuss two considerations relevant to the regulation and equitable access to this type of gene-editing therapy in society.

Extended Response 4: Receptor Tyrosine Kinase Signalling and Cancer

Extended Response 4: Receptor Tyrosine Kinase Signalling and Cancer (a)
Describe the normal receptor tyrosine kinase (RTK) signal transduction pathway that regulates cell division, from ligand binding at the cell surface to the activation of genes controlling the cell cycle.

Extended Response 4: Receptor Tyrosine Kinase Signalling and Cancer

Extended Response 4: Receptor Tyrosine Kinase Signalling and Cancer (b)
Explain how a mutation in the RAS gene (producing a constitutively active Ras protein) can contribute to the uncontrolled cell proliferation seen in cancer.

Extended Response 4: Receptor Tyrosine Kinase Signalling and Cancer

Extended Response 4: Receptor Tyrosine Kinase Signalling and Cancer (c)
In a laboratory study, cancer cells with an activating RAS mutation were cultured with or without a targeted RTK-pathway inhibitor drug. The table below shows the relative number of viable cancer cells (as a percentage of the starting number) over 96 hours.

Time (hours) | Untreated cells (%) | Cells + inhibitor drug (%)
0 | 100 | 100
24 | 150 | 105
48 | 230 | 100
72 | 350 | 90
96 | 520 | 75

Describe the effect of the inhibitor drug shown by this data, including a calculation of the percentage change in cell number for each group between 0 and 96 hours.

Extended Response 4: Receptor Tyrosine Kinase Signalling and Cancer

Extended Response 4: Receptor Tyrosine Kinase Signalling and Cancer (d)
Explain why targeted therapies that block a specific overactive signalling protein (such as an RTK inhibitor) may cause fewer side effects than traditional non-specific chemotherapy, and discuss one limitation of this type of targeted therapy.