Practice Exam 6
VCE Biology Units 1 & 2 | Biotechnology & Genetic Engineering Applications
✎ Complete ALL questions on paper before opening the Model Answers lesson. No notes. Aim for 1 minute per mark.
MULTIPLE CHOICE
Question 1 (1 mark)
Recombinant DNA is best defined as:
✎ Circle your answer
A) DNA that has been artificially synthesised from free nucleotides
B) DNA formed by combining genetic material from two or more different sources
C) DNA that has undergone a natural spontaneous mutation
D) DNA extracted from a single organism only
Question 2 (1 mark)
Restriction enzymes are used in genetic engineering because they:
✎ Circle your answer
A) Join DNA fragments together permanently
B) Cut DNA at specific recognition sequences, often producing complementary “sticky ends”
C) Amplify DNA exponentially
D) Add a poly-A tail to mRNA
Question 3 (1 mark)
A plasmid used as a vector in genetic engineering is:
✎ Circle your answer
A) A linear chromosome found only in eukaryotic cells
B) A small circular piece of DNA found in bacteria, capable of independent replication
C) A section of mRNA used to carry genes
D) An enzyme that cuts DNA
Question 4 (1 mark)
The purpose of the polymerase chain reaction (PCR) is to:
✎ Circle your answer
A) Sequence an entire genome
B) Rapidly produce many copies of a specific DNA sequence
C) Separate DNA fragments by size
D) Insert a gene into a bacterial chromosome
Question 5 (1 mark)
During the denaturation step of PCR, the reaction mixture is heated to approximately:
✎ Circle your answer
A) 37°C
B) 55°C
C) 72°C
D) 95°C
Question 6 (1 mark)
Primers used in PCR are:
✎ Circle your answer
A) Long single strands of DNA polymerase
B) Short single-stranded DNA sequences complementary to the target region, providing a starting point for replication
C) Restriction enzymes that cut the template
D) RNA molecules that code for the target protein
Question 7 (1 mark)
Taq polymerase is favoured for use in PCR because it:
✎ Circle your answer
A) Is inexpensive to purify from human cells
B) Is heat-stable, remaining active at the high temperatures used in the denaturation step
C) Cannot be denatured at any temperature
D) Directly synthesises RNA instead of DNA
Question 8 (1 mark)
In gel electrophoresis, DNA fragments migrate toward the positive electrode because:
✎ Circle your answer
A) DNA is positively charged due to its phosphate backbone
B) DNA is negatively charged due to its phosphate backbone
C) DNA has no charge and moves by diffusion only
D) The gel repels negative fragments
Question 9 (1 mark)
In gel electrophoresis, which fragments travel furthest through the gel in a given time?
✎ Circle your answer
A) The largest fragments
B) The smallest fragments
C) All fragments travel the same distance
D) Fragments do not move through the gel
Question 10 (1 mark)
In the construction of a recombinant plasmid, DNA ligase is used to:
✎ Circle your answer
A) Cut the plasmid open at a specific site
B) Seal the sugar-phosphate backbone, joining the sticky ends of the gene and the plasmid together
C) Amplify the number of plasmid copies
D) Separate the gene from the plasmid
Question 11 (1 mark)
Restriction enzymes typically recognise and cut DNA at:
✎ Circle your answer
A) Any random sequence along the DNA molecule
B) Specific, often palindromic, nucleotide sequences
C) The 5′ cap of mRNA only
D) Telomeres at the ends of chromosomes
Question 12 (1 mark)
Bacterial transformation refers to the process by which bacteria:
✎ Circle your answer
A) Undergo binary fission
B) Take up foreign DNA (e.g. a recombinant plasmid) from their surroundings
C) Convert glucose into ethanol
D) Mutate spontaneously under UV light
Question 13 (1 mark)
An antibiotic-resistance gene is often included on a plasmid vector so that scientists can:
✎ Circle your answer
A) Make the bacteria pathogenic
B) Identify which bacteria have successfully taken up the plasmid, by growing them on antibiotic-containing media
C) Increase the rate of DNA replication
D) Prevent the plasmid from being copied
Question 14 (1 mark)
A genetically modified organism (GMO) is one that:
✎ Circle your answer
A) Has arisen through natural selection alone
B) Has had its genome altered using genetic engineering techniques, often by introducing DNA from another species
C) Has undergone selective breeding only
D) Cannot reproduce
Question 15 (1 mark)
Human insulin used to treat diabetes is now commercially produced by:
✎ Circle your answer
A) Extracting it directly from pig pancreases only
B) Inserting the human insulin gene into bacteria (e.g. E. coli), which then express and produce the protein
C) Chemically synthesising the entire protein from individual amino acids
D) Extracting it from genetically modified plants only
Question 16 (1 mark)
In the CRISPR-Cas9 gene-editing system, the guide RNA functions to:
✎ Circle your answer
A) Provide energy for the Cas9 enzyme
B) Direct the Cas9 enzyme to a specific target DNA sequence via complementary base pairing
C) Replace the need for a DNA template entirely
D) Translate the edited gene into protein
Question 17 (1 mark)
The Cas9 protein in the CRISPR-Cas9 system acts as a(n):
✎ Circle your answer
A) Ligase that joins DNA fragments
B) Endonuclease that creates a double-strand break in the target DNA
C) Polymerase that replicates the whole genome
D) Reverse transcriptase
Question 18 (1 mark)
A key difference between CRISPR-Cas9 and traditional restriction enzymes is that:
✎ Circle your answer
A) CRISPR-Cas9 can be programmed with a guide RNA to target virtually any DNA sequence, whereas restriction enzymes only cut at their fixed recognition sequence
B) Restriction enzymes are more precise than CRISPR-Cas9
C) CRISPR-Cas9 cannot be used in living cells
D) Restriction enzymes require a guide RNA to function
Question 19 (1 mark)
Gene therapy that alters genes in an individual’s somatic (body) cells, rather than their reproductive cells:
✎ Circle your answer
A) Is passed on to the individual’s offspring
B) Only affects the treated individual and is not inherited by their offspring
C) Changes the individual’s entire genome instantly
D) Is identical to germline gene therapy in its ethical implications
Question 20 (1 mark)
A key ethical concern frequently raised about genetically modified crops is:
✎ Circle your answer
A) That they cannot be grown outdoors
B) The potential for gene flow to wild relatives, effects on biodiversity, and corporate control of the food supply
C) That they always increase the cost of farming
D) That they are not able to produce seeds
SHORT ANSWER
Question 21 (5 marks)
Describe the three main steps of one cycle of PCR, including the approximate temperature and purpose of each step.
✎ Write your answer on paper
Question 22 (4 marks)
Describe the steps involved in producing a recombinant plasmid from a human gene of interest and a bacterial plasmid.
✎ Write your answer on paper
Question 23 (4 marks)
Explain the principle of gel electrophoresis and how the resulting pattern of bands is interpreted.
✎ Write your answer on paper
Question 24 (4 marks)
Explain how genetically modified bacteria are used to produce human insulin for medical use.
✎ Write your answer on paper
Question 25 (4 marks)
Explain how the CRISPR-Cas9 system enables precise editing of a targeted gene, and outline one difference between CRISPR-Cas9 and gene editing using restriction enzymes.
✎ Write your answer on paper
Question 26 (4 marks)
Discuss two ethical or social considerations associated with the use of genetically modified organisms.
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Question 27 (4 marks)
Explain what a DNA profile is and describe how it can be used to establish biological relationships or identify individuals.
✎ Write your answer on paper
Question 28 (3 marks)
Explain the difference between somatic and germline gene therapy, including one ethical implication of each.
✎ Write your answer on paper
EXTENDED RESPONSE
Extended Response 1: Producing Recombinant Insulin-Producing Bacteria
Question 29 (3 marks)
Extended Response 1: Producing Recombinant Insulin-Producing Bacteria (a)
Explain why a restriction enzyme that produces “sticky ends” is particularly useful when constructing a recombinant plasmid, compared to one that produces “blunt ends.”
✎ Write your answer on paper
Extended Response 1: Producing Recombinant Insulin-Producing Bacteria
Question 30 (4 marks)
Extended Response 1: Producing Recombinant Insulin-Producing Bacteria (b)
Outline the sequence of steps, from having the isolated insulin gene and a bacterial plasmid, to obtaining a pure colony of bacteria that produce human insulin.
✎ Write your answer on paper
Extended Response 1: Producing Recombinant Insulin-Producing Bacteria
Question 31 (3 marks)
Extended Response 1: Producing Recombinant Insulin-Producing Bacteria (c)
Explain why the antibiotic-resistance marker gene is essential to this process, and describe what would happen if it were left out of the plasmid.
✎ Write your answer on paper
Extended Response 2: CRISPR Gene Editing to Correct a Genetic Disease
Question 32 (4 marks)
Extended Response 2: CRISPR Gene Editing to Correct a Genetic Disease (a)
A research team plans to use CRISPR-Cas9 to correct the mutant allele responsible for a recessive genetic blood disorder in a patient’s bone marrow stem cells. Explain how the CRISPR-Cas9 system would be used to target and edit the mutated gene.
✎ Write your answer on paper
Extended Response 2: CRISPR Gene Editing to Correct a Genetic Disease
Question 33 (3 marks)
Extended Response 2: CRISPR Gene Editing to Correct a Genetic Disease (b)
Explain why editing the patient’s bone marrow stem cells in this way is an example of somatic, rather than germline, gene therapy, and outline one ethical concern that would apply if the same technology were instead used to edit a human embryo.
✎ Write your answer on paper
✓ Finished? Open the next lesson – Model Answers – to mark your work.
