2015 Notes from the Marking Centre – Biology
Introduction
This document has been produced for the teachers and candidates of the Stage 6 Biology course. It contains comments on candidate responses to the 2015 Higher School Certificate examination, highlighting their strengths in (particular (parts of the examination and indicating where candidates need to improve.
This document should be read along with:
- the Biology Stage 6 Syllabus
- the 2015 Higher School Certificate Biology examination
- the marking guidelines
- Advice for students sitting for HSC science examinations
- Advice for HSC students about examinations
- other support documents developed by the Board of Studies, Teaching and Educational Standards NSW to assist in the teaching and learning of Biology in Stage 6.
Section I (part b)
Core
Candidates showed strength in these areas:
- identifying a control measure for malaria ((Q21)
- identifying that DNA is a double-stranded molecule twisted into a helix with each strand, comprised of a sugar-phosphate backbone and attached bases, connected to a complementary strand by pairing the bases (Q23)
- identifying a current technology pulse oximeter that allows measurement of oxygen saturation concentrations in blood (Q24)
- applying a risk assessment to an intended experimental procedure (Q25)
- describing processes responsible for the movement of materials in phloem (Q26)
- describing the structure of arteries/capillaries/veins in relation to their function (Q26)
- identifying some differences between the use of whole blood and products from plasma (Q27)
- describing variables involved in an investigation, identifying variables that need to be kept constant and predicting possible issues and strategies that may arise in an investigation (Q28)
- extracting some information from a graph (Q28)
- discussing the potential impact of the use of reproductive techniques with regard to limiting genetic diversity in species (Q29)
- outlining the Darwin/Wallace theory of evolution by natural selection to explain changes in a population (Q30)
- identifying some trends, patterns and relationships from data and information
- outlining why the immune response is suppressed in organ transplant patients (Q31)
- outlining the role of the kidney for the removal of wastes (Q31)
- distinguishing between active and passive transport and relating these to processes occurring in the mammalian kidney (Q31)
- identifying antigens as molecules that trigger the immune response (Q31).
Candidates need to improve in these areas:
- understanding control measures for a protozoan pathogen like malaria (Q21)
- explaining the relationship between the conservation of water and the production and excretion of uric acid in insects (Q22)
- correctly identifying major parts of a model of DNA (Q23)
- distinguishing between DNA replication and RNA transcription (Q23)
- identifying another current technology arterial blood gas analysis to measure oxygen saturation concentrations in blood and explaining the conditions settings under which such technologies are used (Q24)
- identifying the data that needed to be collected from a first-hand investigation, including identifying variables that needed to be kept constant (Q25)
- comparing the way plants and animals transport dissolved nutrients (Q26)
- identifying the products extracted from plasma (Q27)
- describing passive immunity and active immunity (Q27)
- identifying the components of the immune system (Q27)
- identifying and explaining how data supports or refutes a prediction made (Q28)
- recording results in a table and using appropriate units in an accessible and useful form (Q28)
- answering ‘discuss’ questions by identifying issues and providing points for and/or against (Q29)
- understanding the potential impact (positive and negative) of the use of reproductive techniques with regard to genetic diversity (Q29)
- identifying how reproductive techniques of artificial pollination and cloning may alter the genetic composition of a population (Q29)
- analysing information to generate plausible explanations (Q30)
- outlining the impact of competition for resources on the evolution of animal populations (Q30)
- explaining how mutation in DNA can be the source of variation and provide evidence for evolution by natural selection (Q30)
- comparing the process of renal dialysis with the function of the kidney (Q31)
- explaining why the immune response is suppressed in organ transplant patients (Q31)
- explaining why the processes of diffusion and osmosis are not sufficient in removing dissolved nitrogenous wastes (Q31).
Section II – Options
Question 32 – Communication
Candidates showed strength in these areas:
- extracting some information from a graph/stimulus (parts a, d)
- interpreting a graphical representation of a typical action to identify the resting potential (part a)
- identifying the different ranges of electromagnetic radiation detected by different animals (part b)
- identifying the role of receptors in detecting stimuli (part b)
- identifying those areas of the cerebrum involved in the perception and interpretation of light (part c)
- identifying photoreceptors and explaining that these cells convert light images into electrochemical signals that the brain can interpret (part c)
- identifying the conditions under which refraction of light occurs (part c)
- extracting information and numerical data from a graph/stimulus (part d)
- understanding how hearing aids and cochlear implants assist in hearing (part e)
- describing the problems caused by cataracts, the technology used to prevent blindness and its benefit to society (part e).
Candidates need to improve in these areas:
- understanding ‘threshold’ and explaining not all stimuli generate an action potential (part a)
- describing the nature and function of photoreceptor cells in animals (part b)
- using scientific knowledge to explain phenomenon, conclusions or justify inferences
- explaining why there are different ranges of electromagnetic radiation detected by different animals in the same environment (part b)
- identifying those areas of the cerebrum involved in the perception and interpretation of sound (part c)
- understanding the relationship between sound shadows cast by the head and the location of the sound (part d)
- identifying trends, patterns and relationships as well as contradictions in data or information (part d)
- justifying inference and conclusions based on data in graphs and tables (part d)
- identifying how data supports or refutes a conclusion (part d)
- identifying and explaining the benefits to society of improved biological technologies (part e)
- distinguishing between myopia and hyperopia and outlining how technologies can be used to correct these conditions (part e)
- identifying accommodation and describing how it is achieved and problems corrected (part e).
Question 33 – Biotechnology
Candidates showed strength in these areas:
- identifying and describing the fermentation process, products of fermentation and some modifications to the processes used (part a)
- extracting some information from a graph/stimulus (parts a, d)
- describing changes in a species of grain or animal as a result of domestication and agricultural processes (part c).
Candidates need to improve in these areas:
- using scientific knowledge to explain phenomenon, conclusions or justify inferences
- describing the expansion of fermentation processes to increase yeast biomass (part a)
- describing how to perform a first-hand investigation to extract and identify DNA (part b)
- identifying trends, patterns and relationships as well as contradictions in data or information (part d)
- justifying inference and conclusions based on data in graphs and tables (part d)
- identifying how data supports or refutes a conclusion (part d)
- identifying the use of lactic acid fermentation in the manufacture of cheese (part d)
- outlining how forensic scientists use DNA technologies to solve cases (part e)
- outlining how medical conditions can be treated using applications of biotechnology (part e)
- identifying and explaining the benefits to society of improved biological technologies (part e).
Question 34– Genetics: The Code Broken?
Candidates showed strength in these areas:
- extracting some information from a graph/stimulus (parts a, d)
- describing the processes involved in the transfer of information from DNA through RNA to the production of a sequence of amino acids in a polypeptide (part b)
- describing the effect of genetic mutations on somatic cells compared to gametes (part c)
- identifying current uses of gene technologies (part e)
- identifying the use of highly variable genes for fingerprinting of forensic samples, for paternity testing and for determining the pedigree of animals (part e)
- describing the effect of a genetic mutation on human health (part e).
Candidates need to improve in these areas:
- using scientific knowledge to explain phenomenon, conclusions or justify inferences
- identifying the role of genes in embryonic development (part c)
- summarising the role of gene cascades in determining limb formation (part c)
- identifying the importance of timing of gene expression in the development process (part c)
- identifying trends, patterns and relationships as well as contradictions in data or information (part d)
- justifying inference and conclusions based on data in graphs and tables (part d)
- identifying how data supports or refutes a conclusion (part d)
- explaining how cross-breeding experiments can identify the relative positions of linked genes (part d)
- predicting the differences in inheritance patterns if two genes are linked (part d)
- identifying and explaining the benefits to society of improved biological technologies (part e).
Question 35 – The Human Story
Candidates showed strength in these areas:
- extracting some information from a graph/stimulus (parts a, d)
- identifying differences in cranial capacity as a contributing reason for different cultural developments (part c)
- describing relative dating techniques using fossil sequence in strata (part d)
- distinguishing between relative and absolute dating techniques used for dating fossils (part d).
- extracting some information from a graph/stimulus (parts a, d)
- identifying differences in cranial capacity as a contributing reason for different cultural developments (part c )
- describing relative dating techniques using fossil sequence in strata (part d)
- distinguishing between relative and absolute dating techniques used for dating fossils (part d)
Candidates need to improve in these areas:
- outlining the evidence for the pattern of human migration and evolution based on the theory of regional continuity multi-regional hypothesis (part b)
- using scientific knowledge to explain phenomena, conclusions or justify inferences
- identifying trends, patterns and relationships as well as contradictions in data or information (part d)
- justifying inferences and conclusions based on data in graphs and tables (part d)
- identifying how data supports or refutes a conclusion (part d)
- describing the process of DNA-DNA hybridisation and using the results to determine relationships between organisms (part e)
- explaining the relationships, similarities and differences of organisms classified in the hierarchical classification system (part e)
- identifying and explaining the benefits to society of improved biological technologies (part e).
Question 36 – Biochemistry
Candidates showed strength in these areas:
- extracting some information from a graph/stimulus (parts a, d)
- correctly identifying a component of a model of a photosynthetic unit (part a)
- recognising that photosystems I and II act together (part a)
- identifying the Blackman and Mathgel hypothesis for the photosynthetic process (part b)
- explaining the location of both the light-independent and light-dependent reactions within the chloroplasts (part c)
- outlining how pigments are extracted from leaves (part d).
Candidates need to improve in these areas:
- using scientific knowledge to explain phenomena, conclusions or justify inferences
- explaining the efficiency of photosystem I and II acting together by using the different wavelengths absorbed (part b)
- explaining the significance of the Blackman and Mathgel hypothesis (part b)
- identifying trends, patterns and relationships as well as contradictions in data or information (part d)
- justifying inferences and conclusions based on data in graphs and tables (part d)
- identifying how data supports or refutes a conclusion (part d)
- explaining the use of radioactive tracers to track biochemical processes in photosynthesis (part e)
- identifying and explaining the benefits to society of improved biological technologies (part e).
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