Biology 2018 HSC exam pack (archive)

Students that read each question carefully, highlighted the key components of these questions and addressed each component in their responses and where possible linked their response to the stimulus material used in questions were more successful.

This examination required students to apply their biological knowledge to the scenarios and stimulus given in the questions of the paper.

Students should:

• use relevant scientific terminology rather than general terms in responses – for example, ‘vasoconstriction’ is a much better biological term to use than the general expression ‘blood vessels move away from the surface’
• write a plan for the longer responses to assist in structuring each response in a logical way
• use information from across modules to answer questions where appropriate
• know and be able to apply the scientific skills, including designing valid experiments, considering variables, drawing graphs, identifying trends in graphs, and analysing scientific data presented in different forms
• understand the importance of different types of models in Biology.

Question 21

In better responses, students were able to:

• correctly name an endotherm and identify two correct endothermic responses to a decrease in body temperature (a)
• refer to the marking guidelines (b).

Areas for students to improve include:

• distinguishing between an endotherm and ectotherm (a)
• reading and interpreting the question correctly. For example, some students provided responses that could lower the body temperature, however the question did not ask this (a).

Question 22

In better responses, students were able to:

• state a conclusion from the results of Pasteur’s experiment, for example, ‘disproved the theory of spontaneous generation’ (a)
• justify the conclusion by referring to his experimental results, for example, microbial growth observed in the flask exposed to the air compared to no growth in the swan neck flask not exposed to the air (a)
• link Koch’s discovery that specific pathogens were the cause of certain diseases to the criteria/experiments that he used to prove this (Koch’s Postulates) (b).

Areas for students to improve include:

• linking how Koch’s postulates contributed to our understanding of disease (b).

Question 23

In better responses, students were able to:

• quantify their answers and gave a detailed explanation of how water moves through the Xylem tube.

Question 24

In better responses, students were able to:

• identify that the data was discrete data and therefore were required to draw a column graph.
• describe how a vaccine works and were able to give the contents of vaccines
• explain how a vaccine stimulates an immune response to produce Memory cells that assist with future encounters with the virus.

Question 25

In better responses, students were able to:

• identify the technology as Arterial Blood Gas Analysis (ABG, BGA) (a)
• identify that CO₂ and pH levels were outside the normal range while O₂ levels were within the normal range (b)
• identify and explain the link between pH and CO₂ levels (b).

Areas for students to improve include:

• distinguishing between technologies used to measure different components of the blood (a)
• analysing data rather than just identifying trends (b).

Question 26

In better responses, students were able to:

• provide similarities and/or differences between polypeptides and proteins (a)
• sequentially outline the steps of protein synthesis (bi)
• link the change in the gene to a change in the protein (bi)
• identify an effect of the change in ADH protein on kidney function (bii).

Question 27

In better responses, students were able to:

• explain how nitrogenous wastes, for example urea and uric acid, relate to the conservation of water
• refer to the toxicity of both urea and uric acid
• include features of excretion for both mammals and insects.

Areas for students to improve include:

• understanding the link between the need to remove toxic wastes while conserving water.

Question 28

In better responses, students were able to:

• correctly define genotype and phenotype (a)
• analyse the question carefully to determine the structure of the response (b)
• explicitly identify the genotype, for example M^R, and the phenotype, long thick fur and further link this to natural selection

Areas for students to improve include:

• understanding that phenotype is not simply the physical appearance of an organism (a)
• understanding that reference to punnet squares does not define genotype (a)
• understanding that genotype is of benefit if the selective pressures are present, for example, presence of M^R allele is an advantage in the presence of mite infestations (b)
• carefully addressing the stimulus material in the response (b).

Question 29

In better responses, students were able to:

• focus on the interphase section of the meiosis process to support descriptions of crossing over and random segregation
• use appropriate biological terminology to outline the DNA replication steps
• provide a link to the model.

Question 30

In better responses, students were able to:

• analyse the graphical data and draw conclusions based on biological developments
• demonstrate an extensive knowledge of disease identification and link trends in the data to specific biological developments, for example, Koch’s work and understanding of his postulates or the development of antibiotics and their impact on bacterial pathogens or the development of vaccines and how they create immunity
• make a judgement based on conclusions.

Areas for students to improve include:

• reading and understanding the key points of the question
• the ability to interpret and analyse information in graphical form
• understanding of key words, for example, evaluate requires a judgement to be made and justification provided
• addressing plurals correctly, for example, ‘trends in the data’ required more than one trend to be addressed.

Question 32

In better responses, students were able to:

• include reference to vocal cord changes leading to a change in pitch and frequency when air from the lungs moves passed initiating a vibration in the cords (b)
• refer to each set of the stimulus and each individual (A & B) and explain why there is a difference in colour vision (c)
• draw scientific diagrams that included clear labels and show an understanding of the correct lens shape to refract light appropriately to finish on the retina of the diagram (d)
• use a planned approach that compared a human detection of both visual and auditory stimuli with other organisms and clearly show how models have changed as more knowledge has increased over time (e).

Question 33

In better responses, students were able to:

• link DNA repair with Lynch syndrome and cancer rates to the pattern in the pedigree (c).
• engage with the stimulus material and ensure all components of the questions were addressed (d) and (e)
• provide clear labelled flow diagrams and include the use of biological knowledge that went beyond the identification of examples (d) and (e).

Question 35

In better responses, students were able to:

• interpret graphs appropriately (c)
• demonstrate knowledge of different discoveries relating to human evolution and outline how models were amended based on these discoveries (e).