NESA Biology Causes and Effects
13 sample questions with marking guides and sample answers · Avg. score: 80.1%
Alpha and Beta Thalassemia have similarities and differences in their inheritance patterns. Which of the following is correct?
Both are autosomal dominant conditions controlled on multiple gene loci.
Alpha Thalassemia is fatal for homozygote individuals while Beta Thalassemia is not.
Both are autosomal recessive conditions that result in affected individuals having four defective globin genes.
Beta Thalassemia is fatal for heterozygote individuals while Alpha Thalassemia is not.
Reveal Answer
Both are autosomal dominant conditions controlled on multiple gene loci.
This is incorrect because both Alpha and Beta Thalassemia are inherited as autosomal recessive conditions, not autosomal dominant.
Alpha Thalassemia is fatal for homozygote individuals while Beta Thalassemia is not.
This is correct. Homozygous Alpha Thalassemia (loss of all four alpha genes) causes hydrops fetalis, which is typically fatal in utero. Homozygous Beta Thalassemia is not fatal in utero because fetal hemoglobin relies on gamma chains rather than beta chains.
Both are autosomal recessive conditions that result in affected individuals having four defective globin genes.
This is incorrect because while Alpha Thalassemia involves four genes (two loci on chromosome 16), Beta Thalassemia involves only two genes (one locus on chromosome 11).
Beta Thalassemia is fatal for heterozygote individuals while Alpha Thalassemia is not.
This is incorrect. Heterozygotes for Beta Thalassemia (Beta Thalassemia Minor) are typically asymptomatic or experience only mild anemia, making it non-fatal.
Type 2 diabetes is a condition whereby a person can
produce glucagon but their cells do not respond to it.
produce insulin but their cells do not respond to it.
no longer produce insulin.
no longer produce glucagon.
Reveal Answer
produce glucagon but their cells do not respond to it.
Type 2 diabetes is a disorder of insulin signaling, not glucagon resistance.
produce insulin but their cells do not respond to it.
This correctly describes insulin resistance, which is the primary mechanism underlying Type 2 diabetes.
no longer produce insulin.
The inability to produce insulin is the defining characteristic of Type 1 diabetes, not Type 2.
no longer produce glucagon.
Diabetes is characterized by issues with insulin production or response, rather than a failure to produce glucagon.
One method of assessing the progress of multiple sclerosis (MS) in patients detects fragments of the protein NfL. These protein fragments are released into spinal fluid and blood when nerves are damaged.
It can be expected that patients with progressive MS will have
an increased number of T helper lymphocytes.
lower levels of the NfL protein in the blood.
thicker myelin sheaths around nerves.
lower levels of antibodies.
Reveal Answer
an increased number of T helper lymphocytes.
Multiple sclerosis is an autoimmune disease where the immune system attacks the body's own nerve tissues. This process involves an overactive immune response, including an increased number of T helper lymphocytes coordinating the attack.
lower levels of the NfL protein in the blood.
The prompt states that NfL fragments are released when nerves are damaged. Because progressive MS involves ongoing nerve damage, patients would be expected to have higher, not lower, levels of NfL in their blood.
thicker myelin sheaths around nerves.
Multiple sclerosis is characterized by demyelination, which is the destruction of the myelin sheaths around nerves. Therefore, patients would have thinner or absent myelin sheaths, not thicker ones.
lower levels of antibodies.
Since MS is an autoimmune condition characterized by an overactive immune system, antibody levels would likely be normal or elevated as the body mistakenly targets its own tissues, rather than being lower.
Use the information below on diseases to answer the question.
Disease A is caused by inhalation of viral particles from an infected individual.
Disease B is caused by a soil bacterium infecting a wound.
Disease C is caused by the inheritance of an allele at an X-linked gene.
Disease D is caused by a pathogen transmitted by a tick.
Which of the following statements about the diseases is correct?
Disease B is an infectious disease transmitted by a vector.
Diseases A and B are caused by a pathogen.
Disease C is a sexually transmitted infectious disease.
Disease A is an infectious disease, but Disease D is not.
Reveal Answer
Disease B is an infectious disease transmitted by a vector.
Disease B is transmitted through environmental exposure (soil infecting a wound), whereas vector-borne diseases are transmitted by living organisms like ticks or mosquitoes.
Diseases A and B are caused by a pathogen.
Both viruses (Disease A) and bacteria (Disease B) are types of pathogens, which are biological agents that cause disease or illness to their host.
Disease C is a sexually transmitted infectious disease.
Disease C is a genetic disorder caused by an inherited allele, not an infectious disease transmitted through sexual contact.
Disease A is an infectious disease, but Disease D is not.
Both Disease A (caused by a virus) and Disease D (caused by a tick-borne pathogen) are infectious diseases.
A new treatment for some cancers includes the use of conjugated monoclonal antibodies, which have an anti-cancer drug attached.
The main advantage of using conjugated monoclonal antibodies in this new cancer treatment is that they
decrease the amount of the anti-cancer drug delivered to cancerous cells.
reduce the effects of the anti-cancer drug on non-cancerous cells.
cause an increase in the number of memory T cells.
stimulate B cells to produce antibodies.
Reveal Answer
decrease the amount of the anti-cancer drug delivered to cancerous cells.
Conjugated monoclonal antibodies are designed to specifically target cancer cells, which actually concentrates and increases the delivery of the drug to those cells, rather than decreasing it.
reduce the effects of the anti-cancer drug on non-cancerous cells.
Because monoclonal antibodies specifically bind to antigens found on cancer cells, the attached drug is delivered directly to the tumor. This targeted approach spares healthy, non-cancerous cells from the drug's toxic side effects.
cause an increase in the number of memory T cells.
Monoclonal antibodies provide targeted drug delivery and passive immunity; they do not act as vaccines to stimulate the immune system to produce memory T cells.
stimulate B cells to produce antibodies.
Administering monoclonal antibodies is a form of passive immunity. It delivers pre-made antibodies directly to the patient rather than stimulating the patient's own B cells to produce them.
Use the following information to answer the question.
Gout is a disease that includes swelling, heat and significant pain in a joint, especially in the big toe. It is caused by a build-up of needle-shaped crystals of urate.
The needle-shaped crystals of urate rub against the tissues lining the joint, causing irritation and some tissue damage, which triggers the inflammatory response.
During an attack of gout
dendritic cells in the lining of the joint produce histamines as part of an allergic reaction to crystals of urate, leading to the inflammation.
the inflammation is an innate immune response because crystals of urate are not present in the joints of healthy individuals.
the heat and swelling are caused by the effects of signalling molecules on blood vessels in the tissues of the joint.
neutrophils perform phagocytosis of crystals of urate and act as antigen-presenting cells to B lymphocytes.
Reveal Answer
dendritic cells in the lining of the joint produce histamines as part of an allergic reaction to crystals of urate, leading to the inflammation.
Mast cells, rather than dendritic cells, are the primary producers of histamine. Furthermore, gout is an inflammatory response triggered by tissue damage, not an allergic reaction.
the inflammation is an innate immune response because crystals of urate are not present in the joints of healthy individuals.
While inflammation is an innate immune response, it is triggered by tissue damage or pathogens, not simply because a substance is absent in healthy individuals. Urate is naturally present in the body, though typically not in crystal form.
the heat and swelling are caused by the effects of signalling molecules on blood vessels in the tissues of the joint.
During the inflammatory response, signalling molecules like histamine cause local blood vessels to dilate and become more permeable, which directly leads to the characteristic heat and swelling in the joint.
neutrophils perform phagocytosis of crystals of urate and act as antigen-presenting cells to B lymphocytes.
Although neutrophils are phagocytes that arrive early at the site of inflammation, they do not act as antigen-presenting cells. That role is primarily performed by dendritic cells and macrophages.
DOCK8 syndrome is a disorder in which both B cells and T cells are defective. Patients with DOCK8 syndrome face a range of health issues, including repeated bacterial and viral infections, as well as an increased risk of cancer.
DOCK8 syndrome could be classified as
acquired immunity.
an allergic reaction.
an autoimmune disease.
an immune deficiency disease.
Reveal Answer
acquired immunity.
Acquired immunity refers to the protection developed over time after exposure to specific antigens, not a disorder characterized by defective immune cells.
an allergic reaction.
An allergic reaction is an exaggerated immune response to a typically harmless substance, rather than a lack of functional immune cells.
an autoimmune disease.
An autoimmune disease occurs when the immune system mistakenly attacks the body's own healthy tissues, which is different from having defective B and T cells that fail to fight off infections.
an immune deficiency disease.
DOCK8 syndrome is an immune deficiency disease because it involves defective B and T cells, meaning the immune system is weakened and unable to adequately protect the body from infections and cancer.
Approximately 1 in 25 people from the Ashkenazi Jewish community in Australia will be a genetic carrier for Tay-Sachs as well as other genetic conditions, such as cystic fibrosis. There are several theories as to why the frequency of these genetic conditions is high in the Ashkenazi Jewish population.
A genetic carrier screening program for Tay-Sachs disease was carried out at a high school that has a significant number of Jewish students. One process the specimens were passed through during screening was polymerase chain reaction (PCR).
State what is Tay-Sachs.
Reveal Answer
Any 1 of the following:
- Degenerative neurological disease
- Caused by deficiency of the HexA enzyme
- Disorder of lipid metabolism
- Autosomal recessive disease
| Descriptor | Marks |
|---|---|
1 mark for any one of the following: Degenerative neurological disease; Caused by deficiency of the HexA enzyme; Disorder of lipid metabolism; Autosomal recessive disease | 1 |
Explain how the high incidence of Tay-Sachs within the Ashkenazi Jewish community in Australia is an example of the founder effect.
Reveal Answer
There was a r migration of a small group to Australia, with some or one individual/s carrying the allele for Tay-Sachs disease. Due to restricted breeding within the gene pool, the frequency of the allele increases over time.
| Descriptor | Marks |
|---|---|
Identifies a small original population or migration of a small group to Australia | 1 |
States that some (or one) individuals carried the allele for Tay-Sachs disease | 1 |
Describes restricted breeding within the gene pool or cultural isolation | 1 |
Explains that the frequency of the allele increases over time | 1 |
Outline what occurs in each stage of the PCR process.
- Denaturing:
- Annealing:
- Extension:
Reveal Answer
Denaturing separates complementary base pairs.
Annealing involves adding a primer, which is a small single strand of DNA, to bind to complementary base sequences.
Extension involves DNA polymerase making a copy of DNA strands through a repeated series.
Denaturing
| Descriptor | Marks |
|---|---|
Describes that it separates complementary base pairs, DNA strands separate, or heating separates the DNA | 1 |
Annealing
| Descriptor | Marks |
|---|---|
Describes adding a primer (small single strand of DNA) to bind to complementary base sequences | 1 |
Extension
| Descriptor | Marks |
|---|---|
Describes that DNA polymerase makes a copy of DNA strands through repeated series, elongation, or replication | 1 |
During the Second World War, tuberculosis (TB) ran unchecked in Eastern European Jewish settlements. Often, healthy relatives of children with Tay-Sachs disease did not contract TB, even when exposed repeatedly.
Using the theory of natural selection, explain why Tay-Sachs disease still exists in the Ashkenazi Jewish populations today.
Reveal Answer
Individuals are heterozygous for Tay-Sachs. There is isolation of the gene pool. Individuals that are heterozygous are more likely to survive. Suitable genes are passed onto offspring, while individuals that do not possess suitable genes die off.
| Descriptor | Marks |
|---|---|
States that variation is present in individuals or individuals are heterozygous for Tay-Sachs | 1 |
Identifies isolation of the gene pool or barriers to gene flow | 1 |
Explains that individuals that are heterozygous are more likely to survive, not contract TB, and produce offspring | 1 |
Explains that suitable genes are passed onto offspring or individuals that do not possess suitable genes die off | 1 |
Outline the cause of a disease due to environmental exposure.
Reveal Answer
Lung cancer can be caused by exposure to inhalation of smoke from cigarettes.
| Descriptor | Marks |
|---|---|
Outlines a cause of a disease relating to environmental exposure | 2 |
Provides some relevant information | 1 |
None of the above | 0 |
Explain how an educational program or campaign can be used to decrease the incidence of a disease caused by environmental exposure.
Reveal Answer
An educational program in schools could teach students that UV exposure causes skin cancer, and that to protect from this, they should wear hats and sunscreen when outside. This will help to increase student’s understanding of the risk and therefore increase compliance, and help to prevent the cause of skin cancer (UV rays damaging DNA in cells).
| Descriptor | Marks |
|---|---|
Explains how a program/campaign will help to decrease the incidence of the disease | 3 |
Outlines features of a relevant program/campaign | 2 |
Provides some relevant information | 1 |
None of the above | 0 |
Polycystic kidney is an inherited, genetic disease in cats that may eventually cause kidney failure.
Bovine tuberculosis is an example of a zoonosis.
Identify the four main groups of organisms that cause infectious diseases.
Reveal Answer
Bacterium, protist, fungus, and virus.
| Descriptor | Marks |
|---|---|
Identifies bacterium/bacteria | 1 |
Identifies protist | 1 |
Identifies fungus/fungi | 1 |
Identifies virus | 1 |
State whether polycystic kidney is an infectious disease. Justify your response.
Reveal Answer
No, it is not an infectious disease. The disease is not caused by a pathogen and is not transmitted from one host to another.
| Descriptor | Marks |
|---|---|
States clearly no/not an infectious disease | 1 |
Explains that the disease is not caused by a pathogen | 1 |
Explains that the disease is not transmitted from one host to another | 1 |
Define the term 'zoonosis'.
Reveal Answer
An infectious disease that can be transmitted between vertebrate species.
| Descriptor | Marks |
|---|---|
Defines it as an infectious disease that can be transmitted between vertebrate species | 1 |
Outline how tuberculosis is transmitted.
Reveal Answer
It is airborne. The pathogen is released into the air when infected people breathe, cough, or speak, and is then inhaled by a new host.
| Descriptor | Marks |
|---|---|
1 mark for each correct point (any 2 of):
| 2 |
Explain why antibiotics are used to treat tuberculosis, but not influenza.
Reveal Answer
Tuberculosis is caused by a bacterium, whereas influenza is caused by a virus. Antibiotics affect bacteria but not viruses, as they target cell structures that occur in bacteria but do not occur in viruses. Therefore, influenza is treated with antiviral medication rather than antibiotics.
| Descriptor | Marks |
|---|---|
1 mark for each correct point (any 4 of):
| 4 |
Antibiotic treatment for tuberculosis requires daily doses for four to six months. When treatment was first made available in the 1940s, it was highly effective. Since then, antibiotic resistant strains of tuberculosis have developed.
Explain how these resistant strains have arisen.
Reveal Answer
Natural selection generates resistance, meaning some bacteria are resistant to antibiotics. These resistant bacteria survive and reproduce, while susceptible bacteria do not. As a result, the frequency of the resistant allele increases through time. Bacteria have a short generation time, so resistance will evolve over a short period of time. Furthermore, a long treatment increases the chances that people will not complete the antibiotic course, which increases the chances that some resistant bacterial cells will survive.
| Descriptor | Marks |
|---|---|
1 mark for each correct point (any 5 of):
| 5 |
Christian, a 40-year-old man, was recently diagnosed with Type 2 diabetes. Christian was classified as obese according to his body mass index and his fasting blood glucose level was very high being measured at 10.3 mmol L. In addition to changes to his diet and increased exercise, Christian's doctor prescribed a drug to promote weight loss and lower Christian's blood glucose levels. This drug mimics a natural water-soluble hormone in the human body, enhancing the action of insulin and reducing glucagon levels.
Explain how the following glands maintain blood glucose levels during fasting: ...
Outline how water-soluble hormones influence their target cells.
Reveal Answer
They attach to receptor proteins in the membrane of the target cell, forming a hormone-receptor complex. This activates a secondary messenger inside the cytoplasm or cell, activating particular enzymes, and having a short-lived response.
| Descriptor | Marks |
|---|---|
States that they attach to receptor proteins in the membrane of the target cell | 1 |
Describes the formation of a hormone-receptor complex | 1 |
Explains that this activates a secondary messenger inside the cytoplasm/cell | 1 |
States that this activates particular enzymes/increases enzyme concentration | 1 |
Describes the response as having a fast onset/short-lived response | 1 |
... pancreas
Reveal Answer
Low blood glucose levels are detected by chemoreceptors, and the alpha cells are stimulated. Glucagon is secreted, stimulating glycogenolysis, which is the breakdown of glycogen to glucose, and gluconeogenesis, which is the production of glucose from amino acids and fats. Both of these processes primarily occur in the liver. It also stimulates lipolysis, the breakdown of fats, which occurs in most body cells or adipose tissue.
| Descriptor | Marks |
|---|---|
States that low blood glucose levels are detected | 1 |
Identifies that detection is by chemoreceptors | 1 |
States that the Islets of Langerhans/alpha cells are stimulated | 1 |
States that glucagon is secreted | 1 |
Describes the stimulation of glycogenolysis/breakdown of glycogen to glucose | 1 |
Describes the stimulation of gluconeogenesis/production of glucose from amino acids and fats | 1 |
States that both processes primarily occur in the liver | 1 |
Describes the stimulation of lipolysis/breakdown of fats | 1 |
States that lipolysis occurs in most body cells/adipose tissue | 1 |
... adrenal glands
Reveal Answer
The adrenal medulla secretes adrenaline/noradrenaline, and the adrenal cortex secretes cortisol. This further enhances the rate of glucose production, increasing blood glucose by gluconeogenesis/glycogenolysis.
| Descriptor | Marks |
|---|---|
1 mark for each correct point (any 3 of): States that the adrenal medulla secretes adrenaline/noradrenaline; States that the adrenal cortex secretes cortisol; Explains that this further enhances the rate of glucose production/increases blood glucose; Identifies that this occurs by gluconeogenesis/glycogenolysis | 3 |
Explain why a patient with Type 1 diabetes would not be prescribed the drug from the above scenario to manage their blood glucose levels.
Reveal Answer
Type 1 diabetes is the inability to produce insulin. The drug works to enhance insulin activity, so if there is no insulin being produced, the drug will have no effect.
| Descriptor | Marks |
|---|---|
Defines Type 1 diabetes as the inability to produce insulin | 1 |
States that the drug works to enhance insulin activity | 1 |
Concludes that if there is no insulin being produced, the drug will have no effect | 1 |
Thalassemia is a genetically inherited disorder that affects the haemoglobin of blood. Two types of thalassemia are alpha (α) and beta (β). One of the treatments of both types of thalassemia involves drugs that are administered to help remove excess iron from the blood. A research team wanted to investigate the effectiveness of the different modes of delivery of these drugs.
The team set up an investigation to compare the drugs in injectable form with the orally ingested form. The team conducted their investigation on a sample of 53 beta (β) thalassemia sufferers. The participants were divided into four groups. The participants in each group had daily treatments lasting one month. The groups were:
Group A – 14 participants who received the injectable drug
Group B – 13 participants who received an inactive injectable drug
Group C – 13 participants who received the orally ingested drug
Group D – 13 participants who received an inactive oral drug.
Propose an hypothesis for the study described above.
Reveal Answer
Example: Injectable drugs will be more effective in treating thalassemia symptoms than orally ingested drugs.
| Descriptor | Marks |
|---|---|
Provides a testable, predictive statement (e.g., injectable drugs will be more effective in treating thalassemia symptoms than orally ingested drugs) | 1 |
Why were both groups B and D required for this study?
Reveal Answer
They act as control groups of the study to compare results with. They both administer the placebo treatment to minimise any psychological effects, and the study needs both as there are two different modes of delivery that need to be equally controlled.
| Descriptor | Marks |
|---|---|
Identifies them as control groups of the study to compare results with | 1 |
States that they both administer the placebo treatment to minimise any psychological effects | 1 |
Explains that both are needed as there are two different modes of delivery that need to be equally controlled | 1 |
Identify a variable that was controlled in the study.
Reveal Answer
That all participants have the same type of thalassemia.
| Descriptor | Marks |
|---|---|
Identifies a controlled variable, such as the treatment schedule (daily treatments for a month) or that all participants have the same type of thalassemia | 1 |
Describe the data the researchers would need to collect and when they should collect the data.
Reveal Answer
They should test for the levels of iron found in the blood. Testing should be done before treatment and at the end of the one-month treatment.
| Descriptor | Marks |
|---|---|
States to test for the levels of iron found in the blood | 1 |
States that testing should be done before treatment | 1 |
States that testing should be done at the end of the one-month treatment | 1 |
Outline the cause of alpha (α) and beta (β) thalassemia and identify what makes each type of thalassemia different.
Reveal Answer
It is caused by a mutation of the gene responsible for haemoglobin production.
Alpha () thalassemia affects genes on chromosome 16.
Beta () thalassemia affects genes on chromosome 11.
| Descriptor | Marks |
|---|---|
Identifies a mutation of the gene responsible for red blood cells or haemoglobin production | 1 |
Explains that alpha () thalassemia affects genes on chromosome 16 or reduces the formation of alpha polypeptide chains or the alpha globin of red blood cells | 1 |
Explains that beta () thalassemia affects genes on chromosome 11 or reduces the formation of beta polypeptide chains or the beta globin of red blood cells | 1 |
Alpha (α) and beta (β) thalassemia display the same inheritance pattern but can have differing effects on the gene pool of a population. Justify this statement.
Reveal Answer
Both are recessive traits, and heterozygotes are mildly affected with the disease.
The homozygous condition in alpha thalassemia is fatal, whereas the homozygous condition in beta thalassemia is severe but not fatal. Therefore, there are no homozygote alpha sufferers present in a population, but there will be beta sufferers.
| Descriptor | Marks |
|---|---|
States that both are recessive traits | 1 |
Explains that heterozygotes are mildly affected with the disease or that heterozygous carrier parents pass the traits on to their children | 1 |
States that the homozygous condition in alpha thalassemia is fatal | 1 |
States that the homozygous condition in beta thalassemia is severe but not fatal | 1 |
Concludes that there are no homozygote alpha sufferers present in a population but there will be beta sufferers | 1 |
Changes to the amount of thyroxine being released from the thyroid gland can have major impacts on the functioning of the body.
Name each of the disorders that may lead to an over-secretion or under-secretion of thyroxine; describe how the over-secretion or under-secretion impacts on the body; and explain how each disorder can be treated.
Reveal Answer
Hypothyroidism is a disorder where low levels of thyroxine lead to a decrease in metabolic rate. This causes symptoms such as decreased heart rate and decreased blood pressure. Treatments include increasing iodine in the diet, taking synthetic hormone tablets, or surgery.
Conversely, hyperthyroidism is a disorder where high levels of thyroxine lead to overstimulation of body cells. This causes symptoms such as increased heart rate and high blood pressure. Treatments include taking drugs to block the thyroid's use of iodine, surgery to remove all or part of the gland, or radioactive iodine.
Disorder Identification
| Descriptor | Marks |
|---|---|
Identifies Hypothyroidism/Hashimoto's disease | 1 |
Identifies Hyperthyroidism/Graves' disease | 1 |
Impacts
| Descriptor | Marks |
|---|---|
Describes that low levels of thyroxine lead to a decrease in metabolic rate causing symptoms | 1 |
Describes that high levels of thyroxine lead to overstimulation of body cells causing symptoms | 1 |
Symptoms
| Descriptor | Marks |
|---|---|
1 mark for each correct point (any 2 of) for Hypothyroidism:
| 2 |
1 mark for each correct point (any 2 of) for Hyperthyroidism:
| 2 |
Treatments
| Descriptor | Marks |
|---|---|
1 mark for each correct point (any 2 of) for Hypothyroidism:
| 2 |
1 mark for each correct point (any 2 of) for Hyperthyroidism:
| 2 |
Explain the role of the liver in the maintenance of blood glucose levels.
Reveal Answer
Glucose is removed from blood to provide energy for liver functioning.
Glucose also converted to glycogen by the process of glycogenesis controlled by insulin, and glycogen is stored in the liver.
When blood sugar levels fall glycogen is converted back to glucose by the process of glycogenolysis, which is controlled by glucagon
| Descriptor | Marks |
|---|---|
glucose removed from blood to provide energy for liver functioning | 1 |
glucose also converted to glycogen | 1 |
by the process of glycogenesis | 1 |
controlled by insulin | 1 |
glycogen is stored in the liver | 1 |
when blood sugar levels fall glycogen is converted back to glucose | 1 |
by the process of glycogenolysis | 1 |
controlled by glucagon | 1 |