Biology

Babies born in Australia are tested after birth for phenylketonuria (PKU). Individuals with PKU cannot metabolise the amino acid phenylalanine but can remain healthy if they avoid eating high-protein foods. PKU is a(n):
(A) nutritional disease
(B) environmental disease
(C) infectious disease
(D) genetic disease

E-cigarette operate by vaporising a nicotine containing liquid into an aerosol, which is then inhaled by the user. Since their first introduction to broad global markets in 2007, use has become increasingly common, particularly among youth. They were initially introduced as an alternative to traditional tobacco smoking, with the idea that it could potentially be less harmful due to the absence of tar and combustion products found in tobacco smoke. However, concerns have arisen about the safety and health risks associated with vaping.
Describe and justify an epidemiological study that could be carried out to investigate whether vaping using e-cigarettes causes lung disease.

Human papillomavirus (HPV) is a group of viruses that infect the skin and mucous membranes of humans. HPV viruses are classified into different serotypes based on the DNA sequences of their viral genomes. Each HPV type is identified by a specific number (e.g., HPV-16, HPV-18, etc.). HPV types can cause changes in the cells of the cervix, leading to the development of precancerous lesions. If these lesions are left untreated, they may progress to invasive cervical cancer. HPV binds to the surface of epithelial cells and gain entry via endocytosis. Once inside the cell it introduces its viral DNA into the cells nucleus. It uses the hosts cell’s machinery to produce a viral E6 protein. Schematic of HPV infection of a epithelial cell Adapted from Human Papillomavirus and Oropharynx Cancer: Biology, Detection and Clinical Implications

With reference to protein synthesis, explain how infection of high risk HPV strains can lead to cervical cancer. The graph below shows the ten year cumulative incidence rate of cervical precancer by different HPV serotypes. Patients were tested for HPV at the beginning of the 10 year period.

Birth defects in humans can be caused by chromosomal abnormalities.

Draw a suitable graph of the data provided in the table. Include a suitable line of best fit.

Birth defects in humans can be caused by chromosomal abnormalities.

Outline the trend shown in the data.

A patient felt tired, weak and had a swollen neck. After following the doctor’s advice to eat more foods containing iodised salt, her symptoms disappeared.
What was the most likely cause of the patient’s symptoms?
A. Cancer
B. Genetic disorder
C. Nutritional deficiency
D. Environmental exposure

A pathology centre took blood samples from three patients. One patient was suspected of suffering from anaemia, which reduces the oxygen carrying capacity of the blood. Another patient was suffering from Human immunodeficiency virus (HIV) which attacks T cells. The third patient had a red, raised area following a puncture wound. The table below shows the numbers of different types of blood cells found in blood samples taken from the three patients.

Which of the following correctly matches the patient to the condition?

The human PRNP gene codes for the prion protein. Misfolding of this protein may be the result of ingesting tissue that contains misfolded prion protein or a mutation. Accumulation of misfolded prion protein causes serious diseases such as Creutzfeldt– Jakob disease (CJD).
Which of the following statements best classifies CJD?
A. It is both a genetic disease and an infectious disease.
B. It is a genetic disease only, since it is encoded by a gene.
C. It is not an infectious disease because the prion is non-cellular.
D. It is an infectious disease and the normal prion protein is the pathogen.

Adrenocorticotropic hormone (ACTH) is the hormone that stimulates cholesterol conversion to progesterone and testosterone. Progesterone is then converted to cortisol due to the action of an enzyme 21-hydroxylase. If the enzyme is defective, the synthesis of cortisol is reduced, and an excess of testosterone is produced. This results in a disorder called congenital adrenal hyperplasia (CAH).
To diagnose CAH disorder, an ACTH stimulation test is performed. Blood is measured for starting levels of testosterone. ACTH is then injected, and another blood sample is taken and analysed after 120 minutes.
Using the given key which of the following graphs best depicts the changes in the level of testosterone in an ACTH stimulation test?

Quarantine is ineffective as a measure to control non-infectious diseases because they
A. cannot develop in isolation.
B. depend on long-term exposure to a pathogen.
C. may be inherited and affect the organism all their life.
D. may only be treated by genetic engineering altering cells.

Which of the following is an example of a non-infectious disease?
A. Polio caused by a virus
B. Cholera caused by a bacterium
C. Wheat rust caused by a fungus
D. Haemophilia caused by a gene mutation