Biology 2019 HSC exam pack

Students should:

• communicate succinctly and logically using correct biological terminology
• read carefully the question to ensure that it is understood before responding
• engage with any stimulus material provided and refer to it in their response
• practise skills in applying knowledge to unfamiliar scenarios
• use the key word to answer the question, for example, ‘identify’ the trends rather than explaining the trends
• write a brief plan for longer responses to assist in structuring each response in a logical way
• use skills and information from across modules to answer questions where appropriate.

Question 21

In better responses, students were able to:

• demonstrate a thorough understanding of the reaction to an increase in body temperature
• use correct and precise scientific terminology, for example, vasodilation, hypothalamus, evaporative cooling.

Areas for students to improve include:

• using scientific terminology, rather than general descriptions of processes
• understanding the role of the hypothalamus in detection of internal temperature
• understanding the role of evaporation of sweat in cooling the skin.

Question 22

In better responses, students were able to:

• clearly and succinctly distinguish between somatic and germ-line mutations
• provide a suitable example of a somatic and a germ-line mutation.

Areas for students to improve include:

• presenting information in a concise way
• interpreting the requirements of a table
• understanding the effect of somatic and germ-line mutations on offspring.

Question 23

In better responses, students were able to:

• make the relationships between the decrease in incidences of non-infectious diseases and effective educational programs evident
• use at least two examples of educational programs in their explanation
• communicate their understanding succinctly and logically.

Areas for students to improve include:

• using specific details of actual educational programs to support their general explanations
• addressing plurals correctly, for example, ‘examples’ required more than one example
• addressing the requirements of the question by providing examples of educational programs, rather than screening programs, genetic testing, or government legislation.

Question 24

In better responses, students were able to:

• demonstrate their knowledge of biodiversity
• demonstrate the impacts of biotechnologies on biodiversity, at both a species and ecosystem level
• use specific examples to describe features of relevant biotechnologies
• link the biotechnologies to the loss of biodiversity.

Areas for students to improve include:

• using relevant terminology specific to biodiversity and biotechnologies
• avoiding general comments and instead using a specific example to demonstrate their understanding.

Question 25

In better responses, students were able to:

• engage with the karyotype and correctly identify that the chromosomal mutation is the absence of a sex chromosome (a)
• demonstrate understanding of the process of non-disjunction resulting in the incorrect separation of chromosomes/chromatids during meiosis I or II (b)
• link non-disjunction to the production of gametes lacking a sex chromosome (b)
• explain that fertilisation involving the fusion of the gamete lacking a sex chromosome with a normal gamete produces the karyotype shown (b).

Areas for students to improve include:

• providing specific detail in relation to meiosis and fertilisation rather than general information
• understanding that meiosis, not mitosis, produces gametes (b).

Question 26

In better responses, students were able to:

• identify the presence of milk in the diet as the selective pressure
• link the mutation and selective pressure involved in the process of natural selection to provide reasons for the variation in lactose tolerance.

Areas for students to improve include:

• answering the question using specific detail about DNA and evolution rather than providing general comments
• referring to evolution by natural selection rather than to Lamarckian theory.

Question 27

In better responses, students were able to:

• use correct terminology, such as asexual reproduction (a)
• indicate a method that produced the required temperatures, for example, an incubator (b)
• provides a method of explicitly measuring the dependent variable, or measure the percentage of plate coverage, or use a microscope and mini grid to count the number of colonies present (b)
• identify multiple variables to keep constant. The responses used more accurate or detailed examples such as, ‘use 5g of yeast in each trial’ rather than ‘use the same amount of yeast in each trial’ (b)
• include a number of replications of the trials to increase the reliability of the results, for example, repeat each trial five times for each different temperature (b).

Areas for students to improve include:

• avoiding using generalised information, for example, self-reproduction or non-sexual reproduction (a)
• explicitly outlining how the dependent variable will be measured, for example, ‘place a drop of the liquid from each test tube onto a microscope slide and use a mm grid to count the number of yeast cells present in a given area’, as it is not sufficient to simply measure growth (b)
• providing examples of variables to be kept constant, for example, amount of yeast suspension (5 mL), incubation time (2 hours), to increase the validity of the experiment, understanding that repetition is a necessary requirement to ensure experiments are reliable; even when outlining a procedure, ensure there are sufficient details to enable someone else to reproduce the same experiment (b).

Question 28

In better responses, students were able to:

• correctly identify the alleles for each parent (a)
• correctly and clearly model the process of meiosis, including the correct genotype of the homologous pairs, using the alleles from (a) and (b)
• show that alleles have a specific location on chromosomes (b)
• clearly show crossing over (b).

Areas for students to improve include:

• understanding the difference between allele and genotype (a)
• using all information provided in the stem to determine allele combinations (a)
• using models to simply and clearly represent meiosis (b).

Question 29

In better responses, students were able to:

• articulate that homeostasis requires the detection of changes in the internal environment and not the external environment
• provide multiple features of the mechanism, including the opening and closing of the stomata caused by turgid and flaccid guard cells respectively and linked to increased or decreased transpiration.

Areas for students to improve include:

• understanding that this question was about plant homeostasis and not plant adaptations or photosynthesis
• focusing on a change in the plant rather than a long-term structural feature
• understanding that homeostasis relates to detection of changes in the internal environment and not a response, for example, to increased ambient temperature
• engaging with the question stimulus and structure responses accordingly and in sufficient detail.

Question 30

In better responses, students were able to:

• include two appropriate Punnett squares and relevant phenotype ratios
• recognise the modes of inheritance as autosomal dominant/recessive in Graph A and codominance or incomplete dominance in Graph B
• provide an explanation of the data for the inheritance types by linking the genotype to phenotypic outcomes
• provide an appropriate key to identify the individual alleles represented in each Punnett square.

Areas for students to improve include:

• using an appropriate key to assist the interpretation of the Punnett squares.

Question 31

In better responses, students were able to:

• correctly name a specific pathogen (a)
• identify an adaptation of their chosen pathogen which facilitates entry into a host (a)
• describe how the adaptation assists with entry into the host organism (a)
• outline the different modes of transmission of disease (b)
• identify specific examples of diseases transmitted by these modes (b)
• explain how the mode of transmission for at least one specific disease related to the spread of this disease within or throughout a population (b).

Areas for students to improve include:

• knowing the difference between adaptations for entry and adaptations to avoid the hosts immune system (a)
• demonstrating a clear understanding of the difference between adaptations for entry and those for transmission (a)
• avoiding the use of a disease name instead of a specific pathogen (a)
• correctly interpreting all parts of the question, including the plural ‘diseases’ that requires more than one disease (b).

Question 32

In better responses, students were able to:

• correctly interpret maps and tabulated data (a)
• provide relevant trends in the global disease burden for BOTH malaria and dengue fever (a)
• identify multiple factors and analyse how these factors could have affected the global distribution over time for both dengue fever and malaria (b)
• use the distribution data provided to support the analysis (b)
• provide a logical and succinct response (b).

Areas for students to improve include:

• developing skills in interpreting different types of data to identify trends (a)
• linking trends to the data provided in the question (a)
• using relevant scientific terminology correctly, for example, incidence and distribution, rather than general terms in responses (b).

Question 33

In better responses, students were able to:

• demonstrate their knowledge of the processes of transcription and translation in protein synthesis (a)
• distinguish between the stimulus material and the question asked (a)
• demonstrate a clear understanding of what an allele is and indicate correctly what is meant by the term ‘multiple’ in the context of a single gene, and give appropriate examples to help reinforce their answer (bi)
• extract each of the alleles and engage with the data in the table to draw conclusions about risks associated with the combinations between each of the alleles (bii)
• discuss the data provided beyond repeating information directly from the table (bii)
• identify the dominant and/or recessive alleles as part of their analysis (bii)
• clearly describe the trends of all three lines, recognising the relationship between the cumulative risk of dementia and HSV (c)
• demonstrate their understanding of classifying features of non-infectious and infectious diseases with detailed information, such as definitions for each type of disease, examples of pathogens, modes of transmission, and risk factors for non-infectious diseases, including inherited, nutritional and environmental (d)
• make a suitable judgement using data and information from all parts of the question (d)
• utilise data to support their argument for classification (d)
• correctly analyse data used to support judgement (d)
• articulate a succinct and logical response (d).

Areas for students to improve include:

• demonstrating a clear understanding of both transcription and translation (a)
• defining the term ‘multiple alleles’ without indicating they may be referring to polygenic inheritance (bi)
• developing a response that is clear and succinctly to help show their analysis (bii)
• interpreting graphs to determine the relationship and trend between the variables on the x and y axes (c)
• ensuring the categories of diseases are specifically defined and additional knowledge can be demonstrated (d)
• using a definition of non-infectious disease rather than using ‘not caused by a pathogen’ as a criteria to define non-infectious disease (d)
• using the data and information from other parts of the question to support the argument for classification of Alzheimer's disease (d)
• making reference to all the examples provided in other parts of the question (d)
• avoiding repeating previous analysis completed unnecessarily or without using it to support argument for classification (d).