SCSA Human Biology Science as a Human Endeavour
15 sample questions with marking guides and sample answers · Avg. score: 68.9%
Discuss the ethical implications and impacts on society of the use of TWO biotechnologies.
Reveal Answer
A plant biotechnology that is of benefit to society is recombinant DNA technology eg when used to produce Bt corn or Bt cotton.
Recombinant DNA technology has many ethical implications. For example, Bt corn seeds cost money to purchase each season, while farmers using normal corn seeds can regrow their crops each year from their own seeds. This leads to inequalities in who has access to these GM seeds, and thus access to markets to sell their products.
The use of selective breeding/hybridisation is a type of biotechnology used in animals eg hybridisation of dairy cows to produce greater milk yielding cows. This has ethical implications for example, the side-effect of continuously selecting for greater milk yield has been a decrease in fertility amongst these cows, and may affect quality of life for cows.
However, there are also many benefits to society of the use of recombinant DNA technology or selective breeding/hybridisation. For example:
- the production of more food like Bt corn which can allow the human population to continue to grow, or greater milk availability for consumers in society
- greater yields for farmers, leading to increased profits and quality of life for farmers.
| Descriptor | Marks |
|---|---|
Provides an extensive discussion of the ethical implications and impacts for society of the use of two biotechnologies | 7 |
Provides a thorough discussion of the ethical implications and impacts for society of the use of two biotechnologies | 6 |
The student response meets all criteria of the 4-mark band, and additionally meets the majority of criteria in the 6-mark band. | 5 |
Provides a sound discussion of the ethical implication(s) and/or impact(s) for society of the use of biotechnology/biotechnologies | 4 |
The student response meets all criteria of the 2-mark band, and additionally meets the majority of criteria in the 4-mark band. | 3 |
Demonstrates some understanding of the ethical implication or benefit of the use of a biotechnology | 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 |
Parkinson's disease can potentially be treated using cell replacement therapy. The purpose of using this therapy would be to replace the cells that
would normally function within the cerebral cortex.
would normally function within the cerebellum.
produce dopamine in the brain.
produce noradrenaline in the brain.
Reveal Answer
would normally function within the cerebral cortex.
Parkinson's disease primarily involves the degeneration of neurons in the substantia nigra, a part of the basal ganglia, rather than the cerebral cortex.
would normally function within the cerebellum.
While the cerebellum is involved in motor control, it is not the primary region affected by cell loss in Parkinson's disease.
produce dopamine in the brain.
Parkinson's disease is characterized by the progressive loss of dopamine-producing neurons in the substantia nigra, so cell replacement therapy aims to restore these specific cells.
produce noradrenaline in the brain.
Although noradrenaline levels can be affected in Parkinson's, the hallmark of the disease and the primary target for cell replacement therapy is the loss of dopamine-producing cells.
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.
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.
A promising experimental therapy being used to treat Parkinson's disease involves the use of
stem cells to replace damaged or dysfunctional dopamine-producing neurons.
gene therapy to fix mutated DNA sequences in brain cells.
protein blockers to prevent the building up of amyloid plaques in the brain.
invasive brain stimulation therapy to activate dysfunctional neurons.
Reveal Answer
stem cells to replace damaged or dysfunctional dopamine-producing neurons.
Parkinson's disease is primarily caused by the progressive loss of dopamine-producing neurons. Stem cell therapy is a major experimental approach aimed at differentiating stem cells into new neurons to replace those that have died.
gene therapy to fix mutated DNA sequences in brain cells.
While gene therapy is being researched, most cases of Parkinson's disease are sporadic rather than caused by a single genetic mutation, making direct DNA repair less universally applicable than cell replacement.
protein blockers to prevent the building up of amyloid plaques in the brain.
The buildup of amyloid plaques is a hallmark of Alzheimer's disease, not Parkinson's disease. Parkinson's is instead associated with the accumulation of alpha-synuclein proteins, known as Lewy bodies.
invasive brain stimulation therapy to activate dysfunctional neurons.
Deep brain stimulation (DBS) is an invasive therapy used to treat Parkinson's symptoms, but it is an established, FDA-approved treatment rather than an experimental one.
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.
Restriction enzymes
join DNA into a single strand.
cut DNA at specific locations.
add nucleotides to a growing DNA strand.
assist in the amplification of recombinant DNA.
Reveal Answer
join DNA into a single strand.
This describes the function of DNA ligase, which seals nicks in the DNA backbone, not restriction enzymes.
cut DNA at specific locations.
Restriction enzymes (or restriction endonucleases) recognize specific nucleotide sequences and cleave the DNA at those precise sites.
add nucleotides to a growing DNA strand.
This is the function of DNA polymerase, which synthesizes new DNA strands by adding nucleotides.
assist in the amplification of recombinant DNA.
While restriction enzymes are used to create recombinant DNA, the actual amplification is typically performed by host cells or via PCR using DNA polymerase.
Cell replacement therapy for the treatment of Parkinson's disease involves the
injection of adult stem cells to replace neurons in the brain that have been damaged by the build-up of plaque.
differentiating of stem cells into dopamine-signalling neurons and transplanting them into a patient's brain to replace dying neurons.
patient's own neurons being extracted with the DNA inside the cells then altered and the cells reinserted into the patient's body.
extraction of non-functioning neurons and replacing them with new cells that have the correct gene and can function normally.
Reveal Answer
injection of adult stem cells to replace neurons in the brain that have been damaged by the build-up of plaque.
This option is incorrect because the build-up of plaque is a characteristic of Alzheimer's disease, not Parkinson's disease.
differentiating of stem cells into dopamine-signalling neurons and transplanting them into a patient's brain to replace dying neurons.
This is correct because Parkinson's disease is caused by the loss of dopamine-producing neurons, and cell replacement therapy aims to replace these specific cells by transplanting differentiated stem cells.
patient's own neurons being extracted with the DNA inside the cells then altered and the cells reinserted into the patient's body.
This option describes ex vivo gene therapy rather than cell replacement therapy. Additionally, extracting and reinserting a patient's own neurons is not a feasible treatment for Parkinson's.
extraction of non-functioning neurons and replacing them with new cells that have the correct gene and can function normally.
This is incorrect because cell replacement therapy does not involve the physical extraction of non-functioning neurons; it only involves transplanting new cells to compensate for the dying ones.
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 |
Hepatitis B is a disease that can be prevented via vaccination. The vaccine is developed using recombinant DNA technology. Which of the following statements best describes how the vaccine is produced?
gene of interest is isolated and placed into a plasmid, which is then placed into a bacterial cell, which then produces large quantities of the required vaccine
plasmid is isolated, and a sticky end is produced, which is inserted into a gene; the plasmid is then replicated to produce large quantities of the vaccine
two strands of DNA are isolated from two different species and recombined in a laboratory to create hybrid DNA strands
two genes are cut out of DNA, using restriction enzymes; these genes are then recombined within a plasmid, which is then inserted into a bacterial cell, which can replicate and make large quantities of vaccine
Reveal Answer
gene of interest is isolated and placed into a plasmid, which is then placed into a bacterial cell, which then produces large quantities of the required vaccine
This accurately describes recombinant DNA technology, where the gene coding for the viral antigen is inserted into a plasmid vector and introduced into a host cell (like bacteria or yeast) to produce the vaccine protein in large quantities.
plasmid is isolated, and a sticky end is produced, which is inserted into a gene; the plasmid is then replicated to produce large quantities of the vaccine
This option has the process backward; the gene of interest is inserted into the plasmid, not the plasmid into the gene. Additionally, the vaccine is the protein produced by the host cell, not the replicated plasmid itself.
two strands of DNA are isolated from two different species and recombined in a laboratory to create hybrid DNA strands
While recombinant DNA does involve combining DNA from different sources, this description is too vague and completely omits the crucial steps of using a vector and a host cell to express the vaccine protein.
two genes are cut out of DNA, using restriction enzymes; these genes are then recombined within a plasmid, which is then inserted into a bacterial cell, which can replicate and make large quantities of vaccine
Vaccine production typically requires isolating a single gene of interest (the one coding for the specific antigen), rather than cutting and recombining two different genes within a plasmid.
Refer to the information below.
A study was undertaken by which a small sequence of DNA was inserted into a virus. The virus was injected into veins of rats with Type 1 diabetes. The inserted DNA created cells that produced insulin. The purpose of this study was to find a way for humans suffering from Type 1 diabetes to eliminate the need for daily insulin injections.
The type of therapy used in this study is
recombinant DNA technology.
gene therapy.
hormone replacement therapy.
cell replacement therapy.
Reveal Answer
recombinant DNA technology.
While recombinant DNA technology is the laboratory process used to create the modified virus, it is not the name of the medical therapy itself.
gene therapy.
Gene therapy is the correct term for treating a disease by introducing genetic material (DNA) into a patient's cells, often using a viral vector, to restore a missing function.
hormone replacement therapy.
Hormone replacement therapy involves administering the missing hormone directly (such as daily insulin injections), rather than altering the patient's DNA to produce it naturally.
cell replacement therapy.
Cell replacement therapy involves transplanting whole cells or tissues (like pancreatic islet cells) into a patient, not injecting a virus carrying DNA to modify existing cells.
Target DNA is to be inserted into a plasmid.
For a recombinant plasmid to be produced
the plasmid sections and the target DNA must have blunt ends.
the target DNA must come from the same species as the bacteria.
the plasmid and the target DNA must be cut by a polymerase.
DNA ligase is used to rejoin the sugar-phosphate sections of the plasmid and the target DNA.
Reveal Answer
the plasmid sections and the target DNA must have blunt ends.
While blunt ends can be used, sticky ends (overhangs) are much more commonly used and preferred because they facilitate specific complementary base pairing between the target DNA and the plasmid.
the target DNA must come from the same species as the bacteria.
Recombinant DNA technology frequently involves combining DNA from entirely different species, such as inserting a human gene into a bacterial plasmid.
the plasmid and the target DNA must be cut by a polymerase.
DNA is cut by restriction enzymes (endonucleases), not polymerases. Polymerases are enzymes that synthesize new DNA strands.
DNA ligase is used to rejoin the sugar-phosphate sections of the plasmid and the target DNA.
DNA ligase is the essential enzyme that catalyzes the formation of phosphodiester bonds, permanently joining the sugar-phosphate backbones of the target DNA and the plasmid.
Which stage of making recombinant DNA requires DNA ligase?
cutting
joining
isolation
transformation
Reveal Answer
cutting
Cutting DNA at specific sequences is performed by restriction enzymes (restriction endonucleases), not DNA ligase.
joining
DNA ligase is the enzyme responsible for joining DNA fragments together by catalyzing the formation of phosphodiester bonds between the sugar-phosphate backbones.
isolation
Isolation involves extracting and purifying DNA from cells using lysis and separation techniques, rather than the enzymatic joining of strands.
transformation
Transformation is the process of introducing the already formed recombinant DNA into a host cell, whereas DNA ligase is used in the prior step to construct the molecule.
Use the following information to answer the question.
A bacterial plasmid was modified by inserting a gene for an enzyme that provides resistance to the antibiotic ampicillin. A nutrient solution containing cells of the bacterium Escherichia coli was obtained. E. coli is naturally sensitive to the antibiotic ampicillin. The solution was divided into two equal volumes. The bacteria in one half of the solution were left untreated. Plasmids were added to the other half of the solution and the bacteria were treated to increase their chance of taking up the plasmids.
The next day, the bacterial cells were spread on agar plates as follows:
- Plate 1 – Untreated bacterial cells on nutrient agar
- Plate 2 – Untreated bacterial cells on nutrient agar with ampicillin
- Plate 3 – Treated bacterial cells on nutrient agar with ampicillin
- Plate 4 – Treated bacterial cells on nutrient agar
The plates were incubated overnight.
In order to collect only bacterial cells that had taken up the plasmid successfully, a sample should be taken from
Plate 1.
Plate 2.
Plate 3.
Plate 4.
Reveal Answer
Plate 1.
Plate 1 contains untreated cells on plain nutrient agar. These cells were never exposed to the plasmid, and all of them will grow, so you cannot collect cells with the plasmid from this plate.
Plate 2.
Plate 2 contains untreated cells on agar with ampicillin. Since the cells naturally lack resistance and were not given the plasmid, no cells will survive or grow on this plate.
Plate 3.
Plate 3 contains treated cells on agar with ampicillin. The ampicillin acts as a selective marker, killing any cells that failed to take up the plasmid and allowing only the successfully transformed, resistant cells to grow.
Plate 4.
Plate 4 contains treated cells on plain nutrient agar. Because there is no ampicillin to kill off the unsuccessful cells, both cells that took up the plasmid and those that did not will grow together.