The normal Huntingtin protein has 10–26 repeats of CAG. In Huntington's disease there are 37–80 repeats. This leads to an alteration in the structure of the protein. The graph shows the relationship between the age of onset of Huntington's disease and the number of CAG repeats. Explain the relationship between the number of CAG repeats and the age of onset of Huntington's disease. (2 marks) --- 5 WORK AREA LINES (style=lined) ---
BIOLOGY, M8 2023 HSC 14 MC
Minamata Disease is caused by regular consumption of contaminated fish and shellfish. The symptoms include numbness in the hands and feet, muscle weakness, and damage to vision, hearing and speech.
Pellagra is a disease which causes delusions or mental confusion, diarrhoea, weakness and loss of appetite caused by insufficient levels of iron and niacin.
Wildervanck Syndrome is a condition that affects the bones in the neck, the eyes and the ears, and occurs primarily in females.
Given the information above, which row in the table correctly identifies the classification of these diseases?
Minamata Disease | Pellagra | Wildervanck Syndrome | |
A. | Genetic | Nutritional | Environmental |
B. | Genetic | Environmental | Nutritional |
C. | Environmental | Genetic | Nutritional |
D. | Environmental | Nutritional | Genetic |
BIOLOGY, M8 EQ-Bank 1 MC
What is the main focus of the study of epidemiology?
- Skin diseases
- Changes in the characteristics of a species
- Factors involved in the occurrence, prevalence and spread of disease
- How the body maintains its functions in response to variations in the environment
BIOLOGY, M7 2019 HSC 33d
Alzheimer's disease causes destruction of brain tissue, dementia and eventually death.
The diagram shows the effect of Alzheimer's disease on the brain.
Amyloid beta protein is produced in the human brain throughout life. In people with Alzheimer's disease, it accumulates in excessive amounts.
The gene with the greatest known effect on the risk of developing late-onset Alzheimer's disease is called APOE. It is found on chromosome 19.
The APOE gene has multiple alleles, including e2, e3 and e4 .
The table shows the risk of developing Alzheimer's disease for various APOE genotypes compared to average risk in the population.
A large epidemiological study was conducted. It used historical data to investigate the association between Herpes simplex virus (HSV) infection and dementia. Dementia is caused by a variety of brain illnesses. Alzheimer's disease is the most common cause of dementia.
The study used the records of 8362 patients with HSV infection and 25086 randomly selected sex- and age-matched control patients without HSV infection. Some of the patients with HSV had been treated with antiviral medication.
The graph below shows some results of the study.
Diseases are classified as infectious or non-infectious.
Evaluate whether Alzheimer's disease should be classified as an infectious disease or a non-infectious disease. In your answer, include reference to the information and data provided above. (8 marks)
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BIOLOGY, M8 2019 HSC 1 MC
Which of the following is an example of a non-infectious disease?
- Polio caused by a virus
- Cholera caused by a bacterium
- Wheat rust caused by a fungus
- Haemophilia caused by a gene mutation
BIOLOGY, M8 2021 HSC 19-20 MC
Use the following information to answer Questions 19–20.
Alcohol that is consumed is broken down by the following pathway.
ALDH is the product of the ALDH gene. The normal allele is ALDH1 but many people have the ALDH2 allele, which is associated with an increased risk of cancer.
Scientists have used mouse models to study the effects of ALDH2. They used wild-type mice with ALDH1 alleles and genetically-engineered mice with one or two copies of the ALDH2 allele.
The mice were given a dose of alcohol and the response was measured. The results are shown.
Question 19
The ALDH alleles differ in their
- genome location.
- location in gametes.
- effect on phenotype.
- amino acid composition.
Question 20
What do the data show about the effect of the ALDH2 allele?
- Enzyme activity is highest in homozygous mice.
- Enzyme activity decreases if ALDH2 is present.
- Enzyme activity increases if ALDH2 is present.
- Enzyme activity is lowest in wild-type mice.