Biology HSC Exam Notes

• Question: Which of the following are non-cellular pathogens?

• Options: Bacteria, Fungi, Prions, Protozoa

• Correct Answer: C. Prions

Question 2

• Question: Spinifex resin is used by Aboriginal Peoples and now in medicinal creams. What is this an example of?

• Options: Biotechnology, Selective breeding, Artificial insemination, Genetically modified organisms

• Correct Answer: A. Biotechnology

Question 3

• Question: A chromosome has undergone mutation, with letters representing genes. Identify the type of mutation.

  • Original: ABCDE FG HI

  • Mutated: AB CD E CD EFG H I

• Options: Deletion, Duplication, Inversion, Substitution

• Correct Answer: B. Duplication

Question 4

• Question: Which row correctly identifies components of DNA?

• Options: Various combinations of Phosphate, Ribose, Deoxyribose, Uracil, Thymine

• Correct Answer: The correct answer would have phosphate, deoxyribose, and thymine as components of DNA.

Question 5

• Question: A cell is reproducing. Identify the method of reproduction and the type of organism.

• Diagram: Shows a cell with a cell wall, cell membrane, mitochondria, and undergoing what appears to be budding.

• Options: Budding/Fungi, Binary fission/Bacteria, Production of spores/Plant, Gamete production/Protist

• Correct Answer: A. Budding / Fungi

Question 6

• Question: Karyotypes of male and female fruit flies are shown. How many chromosomes will the egg of a female fruit fly have?

• Correct Answer: A. 2. Fruit flies have 8 chromosomes in their body cells, so the egg cells will have half that number.

Question 7

• Question: How do stomata maintain water balance in plants?

• Options: Closing in hot weather to decrease transpiration, opening in cold weather to decrease transpiration, opening in hot weather to decrease evaporative cooling, closing in cold weather to decrease evaporative cooling.

• Correct Answer: A. They close in hot weather to decrease transpiration.

Question 8

• Question: Trypanosomes cause African sleeping sickness. Identify the pathogen, vector, and method of disease transmission to humans.

• Diagram: Shows transmission from livestock to tsetse fly to humans.

• Options: Various combinations of Trypanosomes/Tsetse fly/Direct, Tsetse fly/Cow/Direct, Trypanosomes/Tsetse fly/Indirect, Tsetse fly/Cow/Indirect

• Correct Answer: C. Trypanosomes/Tsetse fly/Indirect.

Question 9

• Question: A section of a chromosome represents three genes amongst non-coding DNA with marked mutation locations. Which location could produce a new allele for eye color?

• Diagram: Shows Gene 1 (Body colour), Gene 2 (Eye colour), Gene 3 (Wing shape) and mutation locations P, Q, R, S

• Correct Answer: B. Q (as Q is located within the gene for Eye colour)

Question 10

• Question: Francesco Redi's experiment challenged spontaneous generation of maggots. What is correct for this experimental setup?

• Setup: Sealed jar, gauze-covered jar, open jar with rotting meat.

• Options: Sealed jar improves validity, independent variable is meat spoilage, three jars improve reliability, dependent variable is jar covers.

• Correct Answer: C. The use of three jars improves the reliability of the experiment.

Question 11

• Question: Analyze the data showing the proportion of obese adults in Australia by age group and sex in 2017-18. What can be observed from the data?

• Correct Answer: D. The proportion of men who are obese increases from 18% at 18–24 to 35% at 45–54, then decreases to 23% at age 85 and over.

Question 12

• Question: Robert Koch's criteria to establish if an organism causes a disease are listed out of order. Which option correctly orders the steps?

• Steps: Microorganism causes disease when introduced, microorganism is extracted and isolated then cultured, microorganism is extracted from the experimentally diseased animal and is the same as the first, microorganism is found in the diseased animal but not in healthy ones.

• Correct Answer: C. 4, 2, 1, 3

Question 13

• Question: Which of the following identifies plant responses to pathogens?

• Options: Increased phagocytosis and programmed cell death, Increased number of stomata and programmed cell death, Production of antihistamines and increased thickness of cell walls, Production of antimicrobial substances and increased thickness of cell walls.

• Correct Answer: D. Production of antimicrobial substances and increased thickness of cell walls.

Question 14

• Question: The graph shows the quantity of DNA in one mammalian cell over time. Which statement about the cell’s activity is correct?

• Correct Answer: A. The cell is dividing during section O.

Question 15

• Question: The graph shows the number of cases of Swine Flu from May to July 2009 in Australia. What effective control measures could have been introduced between May and July to limit the spread of the disease in Australia?

• Correct Answer: B. Encourage people to wear masks and wash hands regularly. Isolate people with symptoms.

Question 16

• Question: In a person with a visual disorder, light from a distant object focuses in front of the retina. How can this disorder be corrected?

• Correct Answer: B. Use of a diverging lens in front of the eye.

Question 17

• Question: Over 12 months, the prevalence of a non-infectious disease will increase in a population if…

• Correct Answer: D. the survival time of individuals with the disease increases.

Question 18

• Question: The diagram models a population of glowworms in an isolated cave. The letters B and b represent the alleles for a gene in an individual. Which row of the table correctly identifies the process and reason for the change in the gene pool?

• Correct Answer: B. Genetic drift / Change in frequency of the b allele due to random events

Question 19

• Question: The diagram represents some experimental steps used in the production of large amounts of human growth hormone. What makes this technology successful?

• Correct Answer: D. Restriction enzymes can produce sticky ends on both bacterial and human DNA.

Question 20

• Question: Analyze the following four pedigrees and identify the pedigree with the corresponding type of inheritance.

• Correct Answer: Correct answer cannot be determined without the pedigrees.

Section II Notes

Question 21

(a) Identify the structures where pollen and ovules are located.

• Pollen: Anther

• Ovules: Ovary

(b) Complete the table to compare features of sexual and asexual reproduction.

Question 22

(a) Justify a safety precaution required to prevent infection when conducting the investigation.

• Justification: Use of gloves to prevent direct contact with microbes, reducing the risk of infection or contamination.

(b) Explain how the student could ensure the reliability of the investigation.

• Explanation: Repeating the experiment multiple times with the same water and food samples.

Question 23

• Outline how ONE type of electromagnetic radiation can cause a germline mutation.

• Name of electromagnetic radiation: UV radiation.

• Outline: UV radiation can cause thymine dimers, which are covalent linkages between adjacent thymine bases in DNA. If these dimers are not repaired, they can lead to mutations during DNA replication, which may cause germline mutations if they occur in gametes.

Question 24

(a) Outline the cause of a disease due to environmental exposure.

• Name of disease: Lung cancer

• Cause: Prolonged exposure to air pollution, such as particulate matter and chemical pollutants from vehicle emissions and industrial activities, can damage lung tissue and increase the risk of developing lung cancer.

(b) Explain how an educational program or campaign can be used to decrease the incidence of a disease caused by environmental exposure.

• Name of disease: Melanoma

• Explanation: A public health campaign can educate people about the dangers of excessive sun exposure and the importance of sun protection measures, such as wearing protective clothing, using sunscreen, and seeking shade during peak UV radiation hours. By promoting awareness and encouraging behavior changes, the incidence of melanoma can be reduced.

Question 25

(a) Explain why the cloned dog was born with two eyes.

• Explanation: Cloning uses the genetic information from a somatic cell, which already contains the complete set of genes needed to develop all features, including two eyes. The injury (loss of an eye) is not a genetic trait and doesn’t alter the DNA.

(b) Describe how animals like dogs can be cloned.

• Description: Somatic Cell Nuclear Transfer (SCNT) is used. The nucleus of a somatic cell (e.g., skin cell) from the dog to be cloned is inserted into an enucleated egg cell (an egg cell with its nucleus removed). The egg is stimulated to divide, creating an embryo. The embryo is then implanted into a surrogate mother to develop.

Question 26

• Describe a plant disease and its effect on agricultural production.

• Name of plant disease: Panama disease (Fusarium wilt) in bananas

• Description: Panama disease is caused by the fungus Fusarium oxysporum f. sp. cubense, which infects banana plants through the roots and blocks the vascular system, preventing water and nutrient uptake. This leads to wilting, yellowing of leaves, and eventually plant death. The disease has devastated banana plantations worldwide, particularly affecting the Cavendish banana variety, which is the most widely grown for export. The effect on agricultural production is significant yield losses and economic impact on banana-dependent communities.

Question 27

• Explain the trends observed in the graph. In your response, refer to the role of Pasteur’s work in pasteurisation.

• Trends: The graph shows a significant decrease in disease outbreaks related to raw milk from 1900 to 1975, while disease outbreaks related to pasteurized milk remained very low. This trend reflects the increasing adoption of milk pasteurization in America during this period. Pasteur’s work demonstrated that heating liquids (like milk) to a specific temperature could kill most harmful microorganisms, thus preventing diseases like tuberculosis, typhoid fever, and brucellosis. Pasteurisation involves heating milk to approximately 70°C for a specific time.

Question 28

(a) Using a Punnett square, determine the probability of their second child being born with the condition. Use ‘R’ for the normal CFTR allele, and ‘r’ for the faulty CFTR allele.

| | R | r |
| :---- | :- | :- |
| R | RR | Rr |
| r | Rr | rr |

• Probability: The probability of their second child being born with cystic fibrosis (rr) is 25% or $1/4$.

(b) Explain how the deletion of nucleotides in the CFTR gene removes only one amino acid. Include reference to the nucleotides that code for isoleucine and phenylalanine amino acids.

• Explanation: The deletion of three nucleotides in the CFTR gene removes one codon, which results in the removal of one amino acid from the protein sequence. The nucleotides UCA code for the amino acid Isoleucine at position 507, and the nucleotides UUU code for the amino acid Phenylalanine at position 508. The deletion of UCU in the CFTR gene removes only Isoleucine 507 because the genetic code is read in triplets (codons).

Question 29

(a) Plot the data on the grid provided and include the line of best fit.

• (Graph data is not plottable in text format.)

(b) A prediction of the global population numbers suggests there will be about 9 billion (9 000 000 000) people on the planet by 2040.

• Predict the number of people that will be affected by diabetes in 2040. Show working on your graph on the previous page and your calculations.

• Prediction: Draw the continuation of the line of best fit to 2040, and it will be ≈ 7%. Therefore the number of people affected by diabetes will be $0.07 * 9,000,000,000 = 630,000,000$ people affected by Type 2 diabetes.

Question 30

(a) Compare Process A with DNA replication.

• Process A: Transcription

• Comparison:

  • Purpose: Transcription synthesizes mRNA from a DNA template; DNA replication duplicates the entire DNA molecule.

  • Template: Transcription uses a single strand of DNA as a template; replication uses both strands.

  • Product: Transcription produces a single-stranded mRNA molecule; replication produces two double-stranded DNA molecules.

  • Enzymes: Transcription involves RNA polymerase; replication involves DNA polymerase.

  • Location: Both processes occur in the nucleus.

(b) Explain the importance of mRNA and tRNA in polypeptide synthesis.

• Importance:

  • mRNA (messenger RNA) carries the genetic code from DNA in the nucleus to the ribosomes in the cytoplasm.

  • tRNA (transfer RNA) brings the correct amino acids to the ribosome, matching them to the mRNA codons via its anticodon.

  • Polypeptide Synthesis: mRNA provides the sequence information for the polypeptide, while tRNA ensures that the correct amino acids are added in the correct order.

Question 31

(a) At what time was the kookaburra’s body temperature the lowest?

• Lowest Temperature: 5:00 pm

(b) With reference to the graph, explain whether the human or the kookaburra was displaying torpor and if so, state the time this occurred.

• Torpor: The kookaburra was displaying torpor. Torpor is characterized by a significant decrease in physiological activity, including body temperature. The human’s body temperature remains relatively stable. The kookaburra’s body temperature dips to its lowest point at 5:00 pm during its inactive period

(c) Outline an adaptation that may lead to an increase in the kookaburra’s body temperature during the inactive period.

• Adaptation: Shivering (thermogenesis).

• Outline: Shivering involves rapid muscle contractions that generate heat, increasing the kookaburra’s body temperature during its inactive period. This helps the kookaburra maintain a stable body temperature despite fluctuations in environmental conditions.

Question 32

• With reference to innate and adaptive immunity, explain how the body responds after exposure to Helicobacter pylori.

• Response:

  • Innate Immunity:

    • First line of defense involving physical barriers, chemical signals and phagocytes.

    • The innate immune system detects H. pylori via pattern recognition receptors (PRRs) which recognize conserved microbial molecules, in this case H. pylori. This triggers the release of cytokines and chemokines that recruit immune cells to the site of infection; Inflammatory cells such as neutrophils and macrophages are recruited.

    • These immune cells phagocytose the pathogen. In addition H. pylori damage gut lining enabling the innate immune response

  • Adaptive Immunity:

    • These cells present H. pylori antigens to T cells to activate the adaptive system, which is more specific.

    • B cells are activated to create antibodies that bind, neutralize the pathogen, and mark them for destruction. T helper cells assist B cells and enhance cytotoxic T cell response, which then kill infected the cells.

Question 33

(a) Outline the significance of crossing over for the Jack Jumper ants.

• Significance: Crossing over increases genetic diversity by creating new combinations of alleles on the same chromosome. This results in offspring with different combinations of traits, enhancing the population's ability to adapt to changing environments. For Jack Jumper ants, with only a single pair of chromosomes, crossing over is particularly important because single mutations can have drastic effects.

(b) Draw the chromosomes of the four possible gametes after crossing over for the Jack Jumper ants occurs. Include the alleles for each gene.

• (Diagrams cannot be rendered in text.)

Question 34

• Discuss the ethical implications and impacts on society of the use of TWO biotechnologies.

• Biotechnology 1: Genetically Modified Organisms (GMOs)

  • Ethical Implications: Concerns about the safety of consuming GMOs, potential harm to the environment (e.g., pesticide resistance in insects), and economic impacts on small farmers.

  • Societal Impacts: Increased crop yields and nutritional content can help address food security issues. However, there may be resistance from consumers concerned about potential health risks.

• Biotechnology 2: Gene Therapy

  • Ethical Implications: Concerns on equity of access (high costs may limit access to wealthy individuals), the potential for off-target effects (where the therapy affects unintended genes of cells), and the ethical considerations of germline gene therapy (altering genes that can be passed down to future generations).

  • Societal Impacts: Gene therapy offers the potential to cure previously incurable genetic disorders, improving the quality of life for affected individuals. However, there may be broader societal concerns about eugenics and the definition of what constitutes a “desirable” genetic trait.

Question 35

• With reference to the data, describe how cochlear implants work, and how they affect communication in children.

• Function and Effect: Cochlear implants convert sound into electrical signals that stimulate the auditory nerve, bypassing damaged parts of the inner ear. This allows children with severe hearing loss to perceive sounds. The data shows that children with cochlear implants tend to shift from using sign language or a combination of sign and spoken language to primarily using spoken language for communication. This indicates that cochlear implants can significantly improve spoken communication skills in children, enhancing their ability to interact with the hearing world.