NESA Biology Genetic Technologies
15 sample questions with marking guides and sample answers · Avg. score: 70.5%
The function of the CRISPR-Cas9 system in the bacterium S. pyogenes is to
become a recombinant plasmid to produce human insulin.
respond to specific viruses if they reinfect the cell.
act as a promoter for transcription.
increase antibiotic resistance.
Reveal Answer
become a recombinant plasmid to produce human insulin.
While scientists use recombinant plasmids in biotechnology to produce human insulin, this is an artificial application. The natural function of CRISPR-Cas9 is immune defense, not acting as a plasmid.
respond to specific viruses if they reinfect the cell.
In nature, CRISPR-Cas9 acts as an adaptive immune system in bacteria, storing viral DNA sequences to recognize and cleave the DNA of specific bacteriophages upon reinfection.
act as a promoter for transcription.
A promoter is a DNA sequence where RNA polymerase binds to initiate transcription. CRISPR-Cas9 is an RNA-guided endonuclease complex that cuts DNA, not a transcriptional promoter.
increase antibiotic resistance.
Antibiotic resistance is typically conferred by specific genes that degrade or efflux antibiotics. CRISPR-Cas9 defends against foreign genetic material like viruses, not chemical antibiotics.
Compare the processes of artificial insemination and artificial pollination.
Reveal Answer
A similarity is that both processes involve gametes of an organism. A difference is that artificial insemination occurs only in animals while artificial pollination occurs only in (flowering) plants.
| Descriptor | Marks |
|---|---|
Compares artificial insemination and artificial pollination | 3 |
Provides an incomplete comparison of artificial insemination and artificial pollination | 2 |
Provides some relevant information | 1 |
None of the above | 0 |
Gene cloning has allowed the pharmaceutical industry to manufacture large quantities of proteins at a low cost. These proteins are produced by bacteria and are used to treat certain health conditions.
In the past, before the development of DNA technology, proteins for treating certain health conditions could be obtained only from animals, such as cattle and pigs, or from human corpses.
State two advantages of using gene cloning to manufacture pharmaceutical proteins rather than sourcing the proteins from animals or human corpses.
Reveal Answer
| Descriptor | Marks |
|---|---|
1 mark for each correct point (any 2 of):
| 2 |
Outline one ethical issue associated with the use of gene cloning in the manufacture of a pharmaceutical product.
Reveal Answer
For example: Changing a species' DNA may result in unforeseen consequences.
| Descriptor | Marks |
|---|---|
1 mark for each correct point (any 2 of):
| 2 |
Explain the purpose of the polymerase chain reaction (PCR) process and provide an example of its application.
Reveal Answer
Polymerase chain reaction is used to amplify (i.e. make many copies) of a DNA template because usually only a small amount of DNA is available for analysis.
For example, crime scene DNA is sometimes found only at trace levels. PCR amplifies this small amount to allow analysis to be carried out.
| Descriptor | Marks |
|---|---|
Explains purpose of PCR as amplifying a DNA sample for further analysis | 1 |
Provides an example | 1 |
The following table provides information on three commonly grown genetically modified (GM) crops in Australia.
| Crop | Genetic modification | Characteristic given by modification |
|---|---|---|
| GM cotton | several bacterial genes inserted | insect resistance and herbicide tolerance |
| GM canola | two genes from two different bacterial species inserted | tolerance to several herbicides |
| GM safflower | a selection of genes silenced within the safflower genome | elevated levels of oleic acid in its seeds |
Select one of the GM crops in the table above and justify whether or not this crop could be described as transgenic.
Reveal Answer
An acceptable answer was one of the following:
- genetically modified (GM) cotton is transgenic as it contains genes from other species OR bacteria.
- GM canola is transgenic as it contains genes from other species OR bacteria.
- GM safflower is not transgenic as it does not contain genes from another species.
| Descriptor | Marks |
|---|---|
Provides a correct explanation of why the selected crop is or is not transgenic (e.g., GM cotton/canola is transgenic as it contains genes from other species/bacteria, OR GM safflower is not transgenic as it does not contain genes from another species) | 1 |
One issue with GM canola is the accidental release, during transport, of seeds along roadsides. Usually, unwanted plants that grow on the side of the road are killed using the herbicide glyphosate. However, GM canola is resistant to glyphosate.
Suggest one practical solution for treating GM canola that is found growing along roadsides.
Reveal Answer
An acceptable answer was one of the following:
- use a different herbicide that the GM canola is not resistant to
- remove by mowing
- pick the GM canola growing by the side of the road by hand
- use controlled burning.
| Descriptor | Marks |
|---|---|
Provides a correct practical solution to remove the GM canola (e.g., use a different herbicide, remove by mowing, pick by hand, use controlled burning) | 1 |
A new GM canola crop has been approved for use in Australia. It contains increased levels of omega-3 fatty acids, which are important, in humans, for building healthy cell membranes and for general growth and development, and also protect against a wide variety of diseases.
Omega-3 has traditionally been sourced from fish. Due to the growing demand for sources of omega-3, bioengineers have been encouraged to continue developing GM canola crops as a sustainable alternative.
Discuss one social implication and one biological implication of using GM canola with increased levels of omega-3. Use a different implication in each response.
Reveal Answer
Social implication
The correct answer was any one of the following:
- Farmers who grow non-GM canola may sell more canola and the farmer may have an improved quality of life OR may sell less canola and have a decreased quality of life.
- Improved nutrition for consumers and therefore less demand on the health system.
- More people have access to better nutrition as GM canola is cheaper OR more accessible than fish.
- There could be a decreased consumption of fish, which results in fish farmers making less money and having a lower quality of life.
- Consumers may not want to consume GM food. This could lead to consumers not buying enough GM canola and farmers having a lower quality of life.
Biological implication
Accepted responses included any one of the following:
- Possible crossbreeding with non-GM canola crops leading to a change in genome of the crops.
- Potential lack of genetic variation within the GM canola crop. All GM canola plants could then die if there is a change in a selection pressure.
- Consumers may not want to eat or purchase any GM products as these consumers are concerned it is not safe to eat.
- Less fish consumed reduces overfishing, leading to an increase in the fish population.
- Improved nutrition for consumers improves health outcomes for consumers.
Social Implication
| Descriptor | Marks |
|---|---|
Identifies a valid social implication (e.g., economic impact on farmers, improved nutrition for consumers, access to cheaper nutrition) | 1 |
Explains the social implication (e.g., improved/decreased quality of life, less demand on the health system) | 1 |
Biological Implication
| Descriptor | Marks |
|---|---|
Identifies a valid biological implication (e.g., crossbreeding with non-GM crops, lack of genetic variation, impact on fish populations, health outcomes) | 1 |
Explains the biological implication (e.g., change in genome, susceptibility to selection pressures, reduces overfishing, improves health) | 1 |
'Super weeds' are most likely to emerge via
a novel mutation in a weed species.
gene flow from a transgenic crop to a weed species.
natural selection in a weed population.
artificial selection in a weed population.
Reveal Answer
a novel mutation in a weed species.
While a novel mutation could confer herbicide resistance, it is a slow and rare process compared to the rapid acquisition of engineered resistance genes via cross-pollination.
gene flow from a transgenic crop to a weed species.
"Super weeds" often emerge when herbicide-resistance genes from transgenic crops are transferred to closely related wild weed species through gene flow, making them highly resistant to standard weed-control methods.
natural selection in a weed population.
Although natural selection drives the spread of resistant traits once they exist, the sudden emergence of "super weeds" with engineered traits is primarily initiated by gene flow from transgenic crops.
artificial selection in a weed population.
Artificial selection is the intentional breeding of organisms by humans for desirable traits, which does not apply to the unintentional emergence of resistant weeds.
Which of the following is the best description of gene therapy?
mutating the sequence of a particular gene to produce variation
replacing a healthy gene with a defective gene
transferring a gene from one species into the genome of another species
replacing a defective gene with a functional one
Reveal Answer
mutating the sequence of a particular gene to produce variation
This is incorrect because intentionally mutating a gene to create variation describes mutagenesis, not gene therapy. Gene therapy aims to correct existing mutations to treat diseases rather than creating new variations.
replacing a healthy gene with a defective gene
This is incorrect because it describes the exact opposite of gene therapy. The goal of gene therapy is to treat genetic disorders by introducing healthy genes to replace defective ones, not the other way around.
transferring a gene from one species into the genome of another species
This is incorrect because transferring genes between different species describes the creation of transgenic organisms or recombinant DNA technology. Gene therapy specifically focuses on treating genetic diseases within an individual by providing functional genes.
replacing a defective gene with a functional one
This is correct because gene therapy is a medical technique that treats or prevents disease by correcting an underlying genetic problem. It typically involves replacing a mutated, disease-causing gene with a healthy, functional copy to restore normal cellular function.
One-Eyed Jack was a rescue dog that had been injured and lost an eye before his owner adopted him. One-Eyed Jack was cloned and the clone was born with two eyes.
Explain why the cloned dog was born with two eyes.
Reveal Answer
The rescue dog had been injured and lost an eye but it still had the genetic code for two eyes which the clone inherited.
| Descriptor | Marks |
|---|---|
Explains the relationship between the cloning of the dog and being born with both eyes | 2 |
Provides some relevant information | 1 |
None of the above | 0 |
Describe how animals like dogs can be cloned.
Reveal Answer
The egg of a host animal is enucleated (nucleus removed). The nucleus of a body cell of the animal to be cloned is removed. The nucleus of the animal to be cloned is inserted into the enucleated host animal’s egg to produce a zygote. The zygote is stimulated to divide via electric charge. The zygote is then transplanted into the surrogate mother’s uterus. After a period of time, a cloned animal is born.
| Descriptor | Marks |
|---|---|
Describes how animals can be cloned | 4 |
Outlines how animals can be cloned | 3 |
Demonstrates some understanding of the cloning of animals | 2 |
Provides some relevant information | 1 |
None of the above | 0 |
A small sample of DNA was obtained from a fossil. Polymerase chain reaction (PCR) was used to amplify the amount of DNA obtained from the sample.
Which one of the following is a correct statement regarding the PCR process?
DNA polymerase catalyses the pairing of primers with complementary nucleotides.
RNA polymerase catalyses the additions of nucleotides to a DNA strand.
Annealing and extension of the DNA occur at different temperatures.
The number of copies of the DNA is quadrupled in each cycle.
Reveal Answer
DNA polymerase catalyses the pairing of primers with complementary nucleotides.
Primers bind to the template DNA via hydrogen bonding during the annealing phase, which does not require an enzyme. DNA polymerase instead catalyzes the addition of free nucleotides to the primer during the extension phase.
RNA polymerase catalyses the additions of nucleotides to a DNA strand.
PCR utilizes a heat-stable DNA polymerase, such as Taq polymerase, to synthesize new DNA strands. RNA polymerase is used during transcription to synthesize RNA, not in PCR.
Annealing and extension of the DNA occur at different temperatures.
The annealing phase requires a cooler temperature (typically ) for primers to bind, whereas the extension phase requires a warmer temperature (around ) for optimal DNA polymerase activity.
The number of copies of the DNA is quadrupled in each cycle.
The amount of DNA doubles during each cycle of PCR, following exponential growth (), rather than quadrupling.
Genetically modified (GM) crops are engineered to introduce a new trait into a species. Traits chosen by scientists are ones that will benefit people either directly or indirectly.
An example of such a trait is one that
decreases the nutritional value of a crop.
improves environmental conditions for crops.
increases resistance to toxins produced by fungi.
develops potential allergens that trigger a vigorous immune response.
Reveal Answer
decreases the nutritional value of a crop.
Decreasing the nutritional value of a crop would be harmful to consumers, whereas GM crops are typically engineered to increase or maintain nutritional value.
improves environmental conditions for crops.
Genetic modification alters the biological traits of the crop itself, such as drought tolerance, rather than changing the external environmental conditions.
increases resistance to toxins produced by fungi.
Engineering crops to resist fungal toxins protects the plant from disease and prevents harmful toxins from entering the human food supply, providing a clear agricultural and health benefit.
develops potential allergens that trigger a vigorous immune response.
Introducing new allergens would cause adverse health effects in humans, which contradicts the goal of engineering traits that benefit people.
Many genetic diseases are caused by a defect in just a single allele. The ability to replace
a defective allele with a normal or non-defective allele is known as
gene therapy.
cloning.
cell replacement therapy.
stem cell therapy.
Reveal Answer
gene therapy.
Gene therapy is the medical technique of treating genetic diseases by directly replacing, modifying, or supplementing a defective allele with a functional one.
cloning.
Cloning involves creating a genetically identical copy of an entire organism, cell, or DNA sequence, rather than replacing a specific defective gene in a patient.
cell replacement therapy.
Cell replacement therapy involves replacing entire damaged or diseased cells with healthy ones, rather than targeting and replacing a specific allele within a patient's existing cells.
stem cell therapy.
Stem cell therapy uses undifferentiated cells to regenerate or repair damaged tissues, which is a cellular-level treatment rather than directly editing or replacing a specific defective gene.
The following are the five steps in the process of gene cloning.
- Selection of organisms containing recombinant DNA sequences
- Creation of recombinant DNA joined using DNA ligase
- Introduction of recombinant DNA into host organism
- Extraction and amplification of DNA to be cloned
- Choice of host organism and cloning vector
Which is the correct order for this process?
5, 2, 1, 3, 4
5, 4, 2, 3, 1
3, 2, 4, 5, 1
4, 5, 1, 2, 3
Reveal Answer
5, 2, 1, 3, 4
This order is incorrect because it suggests creating recombinant DNA before extracting the target DNA, and selecting organisms before the DNA is even introduced into the host.
5, 4, 2, 3, 1
This is the correct logical sequence: first choose the vector and host, extract the target DNA, ligate it into the vector to create recombinant DNA, introduce it into the host, and finally select the successful transformants.
3, 2, 4, 5, 1
This sequence is incorrect because it starts with introducing recombinant DNA into the host before the target DNA has been extracted or the recombinant molecule has been created.
4, 5, 1, 2, 3
This order is incorrect because it places the selection of organisms containing recombinant DNA before the recombinant DNA is actually created and introduced into the host.
Which genetic tool is not required to make recombinant DNA?
DNA ligase
plasmid vectors
restriction enzymes
transcription factors
Reveal Answer
DNA ligase
DNA ligase is essential for recombinant DNA technology as it acts as molecular glue to join the sugar-phosphate backbones of the DNA fragment and the vector.
plasmid vectors
Plasmid vectors are required to act as vehicles that carry the foreign DNA into a host cell for replication and maintenance.
restriction enzymes
Restriction enzymes are necessary to cut both the vector and the source DNA at specific sequences, creating compatible ends for insertion.
transcription factors
Transcription factors are proteins that regulate gene expression (transcription) inside a cell, but they are not tools used to construct or assemble recombinant DNA molecules.
Describe a named genetic technology and its use in a medical application.
Reveal Answer
Human insulin is produced by recombinant DNA technology to help diabetics.
Restriction enzymes are used to cut the insulin gene from a human cell. The same restriction enzyme is used to cut a section from a plasmid of E.coli to ensure the sticky ends are complimentary. The plasmid is then resealed with the insulin gene inserted. The recombined plasmid is then inserted into a host to produce human insulin.
The insulin is then used by patients to manage diabetes.
| Descriptor | Marks |
|---|---|
Provides a comprehensive description of a named genetic technology and its use in a medical application | 4 |
Provides a sound description of a genetic technology and its use in a medical application | 3 |
Identifies and outlines a genetic technology and its use in a medical application | 2 |
Provides some relevant information | 1 |
None of the above | 0 |
Plant breeders sometimes expose plant seeds to X-rays. This is done to
remove the seed coat to stimulate seed germination.
induce mutations to create different plant varieties.
activate hormones to improve seedling growth.
preserve seeds for long-term storage in seed banks.
Reveal Answer
remove the seed coat to stimulate seed germination.
X-rays are a form of radiation and do not physically or chemically remove the seed coat. Mechanical or chemical scarification is used for that purpose.
induce mutations to create different plant varieties.
X-rays are a type of ionizing radiation that can alter DNA, intentionally inducing mutations to generate new genetic variations and potentially desirable traits in plants.
activate hormones to improve seedling growth.
Seed hormones, such as gibberellins, are typically activated by environmental factors like moisture and temperature, not by X-ray exposure.
preserve seeds for long-term storage in seed banks.
X-rays can damage DNA and reduce seed viability, making them unsuitable for preservation. Seed banks rely on cold, dry environments for long-term storage.