Exam Content Gaps

IgA – protects mucosal surfaces (saliva, mucus and breast milk). IgD – primarily acts as a B-cell antigen receptor. IgE – mediates allergy responses and contributes to defence against parasites. IgG – provides longer-term protection, prevalent in blood and can cross the placenta. IgM – usually produced first in a primary response; effective at agglutination. General antibody actions: Neutralisation – block pathogens/toxins; Agglutination – cross-link pathogens into clumps; Opsonisation – coat pathogens for phagocytosis; some also activate complement. EXAM: The general mechanisms and IgE role matter more than rote-learning all five classes.

Out of Africa/African replacement – Homo sapiens evolved in Africa and dispersed worldwide, largely replacing earlier populations. Multiregional hypothesis – modern humans evolved regionally from earlier populations while gene flow connected populations; the strong form is poorly supported. Out of Africa with interbreeding – an African origin with subsequent interbreeding with Neanderthals and other lineages; this best reflects current genetic evidence. Know approximate time frames and chronological sequence, NOT precise dates for every wave. Early H. sapiens fossils are roughly 200,000–300,000 years old; dispersal beyond Africa occurred in multiple phases.

Ancestors migrated through Southeast Asia to Sahul (the ancient landmass connecting Australia, New Guinea and Tasmania), followed by dispersal and long-term regional occupation. Country – traditionally owned/cared-for lands and waters with physical, spiritual, cultural and ancestral relationships. Place – spaces defined physically or culturally and associated with Torres Strait Islander peoples. Songlines – linked ancestral journeys and cultural knowledge of places, geography and responsibilities. Morphological groupings use shared anatomical features to compare fossils. EXAM: Explain migration evidence and connections to Country/Place; do not memorise particular Songlines or dates for all migration waves.

Fossil distribution – early H. sapiens fossils in Africa and later discoveries elsewhere support African origin; regional morphological similarities were used to argue continuity. mtDNA – maternally inherited DNA sequences accumulate changes, helping infer maternal ancestry and population movements. Whole genomes – compare many markers from both parental lineages to infer shared ancestry, gene flow and interbreeding. Ancient Neanderthal DNA in modern humans supports interbreeding. Australian fossils, archaeological sites and genetic evidence support early settlement through Southeast Asia and long-term population connections. Fossils show anatomical/ geographical patterns; DNA reveals ancestry and admixture.

Mammals – mammary glands, hair/fur, three middle-ear bones and 1 lower jaw bone. Primates – binocular forward-facing vision, grasping hands/feet, opposable digits, relatively large brain and mobile shoulders. Hominoids/apes – no external tail, broad chest, highly mobile shoulders and relatively large brains. Hominins – human lineage characterised by habitual bipedalism: centrally positioned foramen magnum, S-shaped spine, short/ broad pelvis, inward femoral angle, arched feet. Hierarchy: Mammals → Primates → Hominoids → Hominins. EXAM: VCAA specifies no number; aim to recall around three distinctive features per group.

Two specified trends: (1) Generally increasing cranial capacity/ brain size; (2) Increasing leg length relative to arms and skeletal changes supporting efficient bipedalism. Foramen magnum moves more centrally underneath skull (balance); S-shaped spine (upright support); bowl-shaped pelvis (organ support/muscle attachment); inward-angled femurs (knees under centre of mass); arches and aligned big toes (walking efficiency). Evolution forms a branching tree with exceptions, not an inevitable straight-line progression. EXAM: Compare direction and functional advantage; exact species cranial capacities are not required.

* **Live attenuated:** Weakened pathogen that replicates without causing severe disease; provides strong, long-lasting immunity, but risks reverting or causing harm in immunocompromised individuals [Jacaranda 130, 199; Edrolo 802, 803].
* **Inactivated:** Killed/inactivated pathogen that cannot replicate or cause disease; safer for immunocompromised people, but produces a weaker immune response and often requires booster shots [Jacaranda 130, 200; Edrolo 802, 804].
* **Subunit:** Contains only specific isolated antigens of a pathogen; highly targeted with minimal side effects, but generally produces a weaker response requiring adjuvants or boosters [Jacaranda 131, 199; Edrolo 803, 806].
* **Viral vector:** Uses a modified, harmless virus as a vehicle to deliver genetic instructions for the host cell to produce the target pathogen's antigen; elicits a robust immune response, but pre-existing host immunity against the viral vector can reduce efficacy [Jacaranda 172; Edrolo 461].
* **mRNA:** Delivers mRNA strands into host cells to be translated by ribosomes into target antigens; highly adaptable to emerging variants, but RNA and lipid delivery vehicles require strict cold storage [Jacaranda 172, 262; Edrolo 461].

Primary – linear amino acid order, held by peptide bonds. Secondary – α-helices and β-pleated sheets, stabilised by hydrogen bonds between backbone groups. Tertiary – overall 3D fold of one polypeptide, determined by hydrophobic interactions, hydrogen bonds, ionic attractions and disulfide bridges involving R groups. Quaternary – two or more polypeptide subunits assembled through similar interactions. Amino acids contain amino group, carboxyl group and variable R group. Antibodies and Rubisco have quaternary structure. EXAM: No drawing individual amino-acid structures/dipeptides.

1. Damage/pathogens trigger immune signalling; mast cells release histamine and immune cells release cytokines. 2. Histamine induces vasodilation and increases capillary permeability, allowing fluid and immune components to enter tissue. 3. Neutrophils and macrophages migrate into the area and phagocytose pathogens; lysosomal enzymes digest them. Complement proteins assist inflammation, opsonisation and pathogen elimination. Redness/heat – increased blood flow; swelling – fluid accumulation; pain – inflammatory chemicals and pressure. Remember IVM: Initiation → Vasodilation → Migration.

1. Pyrogenic immune signals lead the hypothalamus to raise its temperature set point. 2. Vasoconstriction reduces heat loss, while shivering produces heat. 3. Body temperature rises, potentially restricting some pathogens and supporting immune activity. When pyrogen signalling falls, the set point returns to normal and heat-loss responses occur. EXAM: Understand that the set point rises first; detailed fever stages are supporting knowledge rather than separately named core content.

1. Antigen Presentation (Initial Activation): A "professional" Antigen-Presenting Cell (APC), such as a dendritic cell or macrophage, engulfs a pathogen via phagocytosis. 2. Migration & Presentation: The APC travels through the lymphatic system to a lymph node (secondary lymphoid tissue) and displays the digested antigen fragments on its MHC-II markers. 3. Th Cell Clonal Selection: A naïve Helper T (Th) cell with a receptor complementary to the specific antigen binds to the APC's MHC-II/antigen complex, marking the moment of clonal selection for the Th cell. 4. Th Cell Clonal Expansion: Once selected, the Th cell undergoes clonal expansion (many cycles of mitosis) to produce a large population of identical effector Th cells and memory Th cells. 5. Independent B Cell Selection: Independently, a naïve B cell binds directly to the same raw antigen via its membrane-bound antibodies—this is the moment of clonal selection for the B cell. 6. B Cell Presentation: This selected B cell internalises the antigen and displays it on its own MHC-II markers to a previously activated effector Th cell. 7. Cytokine Signal: The effector Th cell recognises this antigen and releases cytokines (specifically interleukins) to "license" and activate the B cell. 8. B Cell Clonal Expansion: These cytokines trigger the B cell to undergo its own clonal expansion to produce a large population of identical cells. 9. Differentiation: These B cells differentiate into plasma B cells (active responders) and memory B cells (remain in the lymph node for long-term protection). 10. Effector Response: Plasma cells secrete massive amounts of soluble antibodies that travel through the blood and lymph to neutralise, agglutinate, or opsonise the specific pathogen.

1. Antigen Presentation: A professional APC (e.g., a dendritic cell) phagocytoses a pathogen and displays the pathogenic antigens on its MHC-II markers. 2. Migration: The APC travels through the lymphatic system to a lymph node. 3. Th Cell Clonal Selection: The APC presents the antigen to a naïve Helper T (Th) cell with a complementary receptor; this binding is the clonal selection of the Th cell. 4. Th Cell Clonal Expansion: The activated Th cell undergoes clonal expansion, proliferating into a large population of effector Th cells and memory Th cells. 5. Tc Cell Selection (The "First Signal"): Independently, a naïve Cytotoxic T (Tc) cell binds its specific receptor to a complementary antigen displayed on the MHC-I marker of an infected self-cell or an APC. This binding is the clonal selection of the Tc cell. 6. Cytokine Release (The "Second Signal"): An activated effector Th cell releases cytokines (interleukins) to the selected Tc cell to fully activate it. 7. Tc Cell Clonal Expansion: Upon receiving the cytokine signal, the Tc cell undergoes clonal expansion, dividing rapidly to produce many identical copies. 8. Differentiation: These cells differentiate into effector Cytotoxic T cells and memory T cells. 9. The Kill: Effector Tc cells leave the lymph node, identify body cells displaying that specific antigen on MHC-I, and induce apoptosis (programmed cell death) using perforin (to create pores) and granzymes (to trigger the death pathway).

1. Sensitisation – first exposure induces allergen-specific IgE; IgE binds mast-cell receptors. 2. Re-exposure – allergen cross-links mast-cell-bound IgE. 3. Mast cells degranulate, releasing histamine and other mediators that cause inflammation, potentially ranging from mild to severe. Keywords: allergen, IgE, mast cell, cross-linking, histamine, inflammation.

Antigenic drift – gradual accumulation of mutations in viral genes coding for antigens, creating relatively small changes. Antigenic shift – abrupt, major antigenic change, commonly when segmented viruses reassort genomic segments between strains. Both may reduce recognition by existing immunity. Drift = gradual; Shift = sudden major change.

1. Extract target RNA. 2. Reverse transcriptase synthesises complementary DNA (cDNA). 3. PCR: denaturation (~95°C) breaks DNA hydrogen bonds; annealing (~50–65°C) allows target-specific primers to bind; extension (~72°C) uses thermostable polymerase and DNA nucleotides to extend strands. 4. Repeat amplification cycles and detect product, potentially with fluorescence. Limitations – RNA degradation; contamination/false positives; inhibitors/false negatives; mutations at primer-binding sites; specialised equipment; presence of viral nucleic acid does not necessarily mean infectious virus. Reverse-transcription PCR and real-time PCR are distinct terms.

Early unicellular organisms → eukaryotes → multicellular life → major diversification of animal life (Cambrian explosion) → expansion/diversification of terrestrial plants and animals → diversification of later groups including mammals and birds → much later hominin evolution. Mass extinctions can remove lineages, followed by diversification of survivors. EXAM: Know faunal succession and relative chronology; specific geological dates and period names are not required.

1. Obtain intron-free DNA for separate human insulin A and B chains. 2. Cut each DNA insert and a suitable plasmid using compatible restriction enzymes. 3. DNA ligase forms phosphodiester bonds, creating two recombinant plasmids. 4. Transform two separate bacterial populations using the plasmids. 5. Select plasmid-bearing bacteria and identify successful recombinant inserts using markereporter methods. 6. Culture bacteria; each expresses an insulin-containing fusion protein. 7. Isolate/purify proteins, separate insulin chains from the fusion partner and combine A+B to make functional insulin. EXAM: VCAA specifies two plasmids/two bacteria and β-galactosidase reporter role; detailed chemistry of its detection is not required.

Direct – an enzyme-linked antibody binds an immobilised antigen. Indirect – sample antibodies bind known antigen, then enzyme-linked secondary antibody detects them. Sandwich – capture antibody binds sample antigen, then a detection antibody binds antigen; substrate produces colour. Competitive – sample analyte competes for limited antibody/antigen binding; signal usually decreases as target concentration increases. General principle: immobilise target → bind complementary antigen/antibody → wash → enzyme-linked detector → substrate → observable signal. EXAM: Know antigen-antibody specificity and interpreting assays; full protocols for every type are not explicitly required.

C3 – CO₂ is fixed directly by Rubisco in the mesophyll Calvin cycle; can experience substantial photorespiration when hot/dry. C4 – CO₂ first fixed by a selective enzyme in mesophyll cells → transported in a carbon compound → released in bundle-sheath cells for the Calvin cycle; spatial separation concentrates CO₂ around Rubisco. CAM – stomata open at night for CO₂ fixation/storage; close during day while stored CO₂ is released for the Calvin cycle; temporal separation conserves water. Memory: C4 = Space; CAM = Time. EXAM: No need to memorise intermediate molecules of extra pathways.

Light-dependent reactions (thylakoid membranes): inputs = light, H₂O, ADP + Pi, NADP⁺; outputs = O₂, ATP, NADPH. Calvin cycle (stroma): inputs = CO₂, ATP, NADPH; outputs = carbohydrate (ultimately glucose), ADP + Pi and NADP⁺. Splitting water supplies replacement electrons and produces oxygen. ATP supplies energy and NADPH supplies reducing power. EXAM: Know both stages' locations, main inputs and outputs; specific intermediates of the Calvin cycle are not required.

Waxy cuticle – reduces evaporation. Epidermis – protects leaf. Palisade mesophyll – densely packed chloroplasts, major photosynthesis site. Spongy mesophyll – air spaces permit gas exchange; also photosynthesises. Stomata – openings for gas exchange. Guard cells – regulate stomatal aperture. Xylem – water/mineral transport. Phloem – sugar/organic compound transport. Bundle sheath – surrounds vascular tissue and is the Calvin-cycle cell type in C4 plants. EXAM: Prioritise understanding mesophyll/stomataundle sheath in photosynthesis examples.

1. Helicase separates complementary strands by breaking hydrogen bonds. 2. Primase makes short RNA primers. 3. DNA polymerase extends the new complementary DNA strands. 4. Leading strand is made continuously; lagging strand in Okazaki fragments. 5. RNA primers are removedeplaced and ligase seals phosphodiester backbone nicks. 6. Two semiconservative molecules result, each with one original and one newly synthesised strand. EXAM: Supporting knowledge useful for PCR comparison; complete cellular replication steps are not separately prescribed.

Neutrophils – rapid phagocytosis. Macrophages – phagocytosis, cytokines, antigen presentation. Dendritic cells – professional antigen presentation/naïve T-cell activation. Mast cells – histamine release. Eosinophils – parasite defence/allergy. Natural killer cells – innate cytotoxic defence. B lymphocytes – antigen recognition; plasma cells – secrete antibodies; memory B cells – faster secondary humoral response. Helper T cells – coordinate adaptive response with signals/cytokines. Cytotoxic T cells – apoptosis of infected/abnormal cells. Memory T cells – support secondary cellular responses. Complement and interferons are non-cellular immune components.

CAR T-cell: collect patient T cells → engineer chimeric antigen receptors specific to cancer-associated surface antigen → expand cells → reinfuse → modified T cells attack targets. Dendritic-cell therapy: prepare antigen-presenting dendritic cells exposed to tumour antigens → administer them → stimulate anti-tumour T cells. Monoclonal antibodies (mAbs): identical antibodies target an epitope to block signals, recruit immune destruction or deliver treatment. Hybridomas: immunise → collect B cells → fuse with myeloma cells → select desired clones → harvest antibody. EXAM: mAb therapy is specifically core; detailed CAR T/dendritic methods are supporting extensions.

Controlled experiment – deliberately changes an independent variable and measures dependent variable with controls. Correlational study – measures relationships without deliberate manipulation. Case study – detailed investigation of a specific situation. Classification/identification – groups or identifies specimens. Fieldwork – collects observations/data in natural settings. Literature review – synthesises existing published research. Modelling – constructs a simplified representation of a system. Simulation – uses a model to imitate/test system behaviour. Product/process/system development – designs or improves an artefact/method. EXAM clue: experiment manipulates; correlation observes; simulation runs a model.

Natural CRISPR – prokaryotic adaptive defence: stored phage DNA spacers in a CRISPR array guide a Cas protein to matching viral DNA on reinfection, allowing cleavage. Engineered CRISPR-Cas9 – synthetic sgRNA guides Cas9 endonuclease to a selected PAM-adjacent DNA target in an organism so DNA breaks and subsequent repair can alter a gene. Natural = microbial defence; engineered = genome editing.

* **crRNA (CRISPR RNA):** Contains the foreign viral **spacer RNA** (the targeting sequence complementary to target DNA) attached to a transcribed **repeat section**.
* **tracrRNA (trans-acting CRISPR RNA):** Base-pairs with the crRNA **repeat section** and serves as the scaffold sequence that binds directly to the **Cas9 enzyme**.
* **Single-Guide RNA (sgRNA):** A synthetic single strand used in gene editing that fuses the **spacer RNA** (targeting region from crRNA) and **scaffold region** (Cas9-binding region from tracrRNA) into one molecule.
* **VCE Exam Distinction:** Natural bacterial gRNA is a **crRNA:tracrRNA duplex**, whereas engineered gene editing uses a single-stranded **sgRNA**.

Natural: (1) phage infects bacterium; (2) phage-derived spacer is inserted between CRISPR repeats; (3) CRISPR DNA is transcribed/processed into guide RNA which complexes with Cas9; (4) on reinfection, Cas9 recognises PAM and complementary target DNA; (5) Cas9 cleaves viral DNA, interfering with infection. Engineered: design sgRNA complementary to chosen target beside suitable PAM → deliver sgRNA and Cas9 → recognise PAM/target → double-strand cut → cell repairs DNA. Error-prone end joining may cause insertion/deletion/knockout; template-directed repair can introduce intended edit if a suitable template exists; accurate repair may restore unchanged DNA. A cut does not guarantee a desired mutation.

Increase photosynthetic efficiency, increase crop yields, and increase disease/stress resistance. Examples: edit pathways affecting carbon fixation/photorespiration; alter genes affecting productivity or resource use; modify susceptibility to pathogens/environmental stresses. EXAM: Higher photosynthetic efficiency and higher crop yield are the two VCAA-specified teaching examples; recognise broader uses in unfamiliar scenarios.

Single-guide RNA. A designed RNA that contains a targeting sequence complementary to selected DNA and a Cas9-binding scaffold, directing Cas9 to a specific sequence close to a suitable PAM. VCAA distinguishes engineered sgRNA from natural bacterial guide RNA.

Transfer RNA. Transfers a specific amino acid to a ribosome during translation; its anticodon base-pairs with a complementary mRNA codon so the correct amino acid is added to a growing polypeptide.

In bacteria, transcription and translation can be coupled in the cytoplasm; a ribosome translating a leader sequence can influence RNA polymerase termination. In eukaryotes, transcription is mainly nuclear and translation cytoplasmic, so the same coupled attenuation mechanism cannot operate. Eukaryotic genes usually have independent regulatory elements. Avoid the absolute claim that eukaryotes never contain operon-like gene arrangements.

Positive control – known to contain the target/produce a positive result; demonstrates assay can detect what it claims. Negative control – target absent/expected negative result; reveals contamination, background or nonspecific reaction. PCR: positive = known target DNA; negative = no target DNA. Positive-control failure suggests procedureeagent issue; negative-control signal suggests contamination or lack of specificity.

Initiation – transcription factors (eukaryotes) and RNA polymerase associate with promoter; DNA locally unwinds. Elongation – RNA polymerase reads template DNA and polymerises complementary RNA nucleotides (A pairs U, T pairs A, C pairs G). Termination – transcription ends in response to sequence signals and RNA transcript is released. In eukaryotes, protein-coding transcription creates pre-mRNA in nucleus. STOP CODON ends translation, not transcription.

Transcription factor – protein influencing transcription by interacting with DNA or transcription machinery. Structural gene – encodes functional product such as tryptophan-biosynthesis enzyme. Regulatoryepressor gene – encodes regulatory product such as trp repressor. Repressor protein – binds relevant regulatory DNA (e.g. operator) and reduces/prevents transcription. EXAM: The gene is DNA; the transcription factorepressor is protein.

Cap → Tail → Remove → Splice. Add modified guanine cap to one end and poly-A tail to the other to stabilise mRNA and assist its function. Remove introns with splicing machinery and join retained exons to produce mature mRNA. Alternative splicing produces different exon combinations, increasing possible protein products. Processing events are not necessarily in strict chronological order. EXAM: 5′ and 3′ terminology is not required.

Initiation – ribosome binds mRNA and recognises AUG start codon; initiator tRNA brings methionine. Elongation – complementary tRNA anticodons pair with mRNA codons and amino acids are joined by peptide bonds as ribosome moves along mRNA. Termination – stop codon recruits a release factor and polypeptide is released. Translation occurs on free cytosolic or rough-ER-bound ribosomes in eukaryotes. Codon = three nucleotides.

Epidemic – incidence of a disease significantly above expected levels in a particular populationegion. Pandemic – epidemic with sustained spread across multiple countriesegions of the world. Endemic – disease continually present at a relatively expected background level. Pandemic describes geographical spread, not necessarily lethality.

The leader mRNA can fold into alternate hairpins. At high tryptophan, abundant charged tRNA-Trp permits continuous translation through two consecutive Trp codons in the leader; a terminator hairpin forms and RNA polymerase stops before trp structural genes. Region 3–4 pairing is a terminator; region 2–3 pairing can form an antiterminator when Trp is scarce. EXAM: High-Trp hairpin and premature termination ARE required; exact numbered pairings and low-Trp mechanism are NOT required.

Validity – investigation measures what it claims to measure. Accuracy – closeness to true value. Precision – repeated values close to each other. Repeatability – consistent measurements under same method/conditions. Reproducibility – agreement under changed observers, equipment, methods or settings. Reliability – broader dependability/consistency of results. Improve validity by controlling confounders; accuracy by correcting calibration/systematic errors; precision by reducing random error; reproducibility by independent replication. VCAA formally defines the first five; reliability is broader usage.

Glycolysis (cytosol): glucose → 2 pyruvate + 2 NADH + net 2 ATP. Link reaction (mitochondrial matrix): 2 pyruvate → 2 acetyl-CoA + 2 CO₂ + 2 NADH; 0 ATP. Krebs cycle (matrix): acetyl-CoA is oxidised, producing CO₂, NADH, FADH₂ + net 2 ATPlucose. Electron transport/oxidative phosphorylation (inner mitochondrial membrane): NADH/FADH₂ donate electrons, O₂ is terminal electron acceptor and H₂O forms; ~26 or 28 ATP. TOTAL ~30 or 32 ATP per glucose. EXAM: Main stage inputs, outputs, locations and yield; not all intermediates.

Glycolysis converts glucose into 2 pyruvate, producing net 2 ATP and 2 NADH. Fermentation regenerates NAD⁺ to allow glycolysis to continue. Lactic acid fermentation (animals): 2 pyruvate + 2 NADH → 2 lactate + 2 NAD⁺. Alcoholic fermentation (yeast/some plants): 2 pyruvate + 2 NADH → 2 ethanol + 2 CO₂ + 2 NAD⁺. Both processes yield net 2 ATP per glucose, from glycolysis rather than fermentation itself.

Natural – acquired without deliberate medical intervention, e.g. infection or maternal antibody transfer. Artificial – induced by medical intervention, e.g. vaccination or injected antibodies. Natural/artificial tells HOW immunity is obtained; active/passive tells whether host produces its own immune response.

Active – own antigen-specific immune response creates effector and memory cells; usually slow initially but potentially long-lasting. Passive – receive pre-made antibodies; immediate but temporary protection without new immunological memory. Natural active = infection; artificial active = vaccination; natural passive = maternal antibody transfer; artificial passive = therapeutic antibody administration.

Judges ethical action by the decision-maker's good moral character/virtues – e.g. honesty, integrity, compassion and courage – rather than simply outcomes or fixed duties. It asks what a virtuous person ought to do.

Bacteria – cellular prokaryotes. Fungi – cellular eukaryotes (yeast/moulds). Protists/protozoa – diverse cellular eukaryotes, some parasitic. Parasitic animals – multicellular eukaryotic parasites. Viruses – acellular DNA or RNA packaged in a protein capsid, sometimes enveloped; use host machinery to replicate. Prions – infectious misfolded proteins lacking nucleic acid. EXAM: Compare cellular versus non-cellular structures and reproduction; specific parasite species are not required.

Prokaryotes – no membrane-bound nucleus/organelles; typically circular chromosome in nucleoid and sometimes plasmids; 70S ribosomes; coupled transcription/translation; usually binary fission. Eukaryotes – membrane-bound nucleus/organelles; usually linear nuclear chromosomes; 80S cytosolic ribosomes; nuclear transcription and cytoplasmic translation; mitosis/meiosis. Both have plasma membrane, DNA, cytoplasm and ribosomes.

Scientific – medical/technical practices based on biological knowledge, such as vaccines, diagnostic testing, antivirals, antibiotics and surveillance. Social – community behaviour, policy or communications such as public education, isolation, hygiene campaigns and reducing exposure. EXAM: Explain mechanism by which chosen strategy disrupts the pathogen's specific transmission route.

Direct contact – close bodily contact/fluids. Indirect contact – contaminated surfaces/objects. Droplet – respiratory droplets typically deposited at shorter distances. Airborne – inhalation of suspended infectious particles. Oral/foodborne/waterborne – ingestion of contaminated food/water. Vector-borne – infected living vector transmits pathogen. Zoonotic – transfer from animal to human. OI DAD is a personal memory aid, not the official VCAA classification.

P – Physical: visual characteristics/microscopy. I – Immunological: antigen-antibody binding (e.g. ELISA). M – Molecular: genetic material detection by PCR, probe or sequencing. P – Phenotypic: culture characteristics, staining and biochemical activity. EXAM: Be able to interpret diagramsesults and recognise the principle; not every laboratory protocol needs memorisation.

Radiometric dating estimates absolute age from parent isotope decay/daughter-product buildup. Carbon-14 – dates suitable relatively recent once-living material; half-life ~5,730 years. Potassium-argon – dates some volcanic rocks. Uranium-lead – dates some very old minerals/ rocks. Half-life fractions: after 1 = 50% remaining, 2 = 25%, 3 = 12.5%. EXAM: Carbon-14 is required; other isotopes' details are not.

Virulence – degree of harm or severity of disease caused. Infectiousness – ability to establish infection in susceptible host. Contagiousness – ease of spread between hosts, especially through direct/near-direct transmission. Highly contagious does not necessarily mean highly virulent.

VIDR = Variation → Isolation → Divergence → Reproductive isolation. 1. Mutation/existing alleles produce variation. 2. Barrier reduces gene flow between populations. 3. Mutation, different environmental selection pressures and genetic drift independently change allele frequencies. 4. Sufficient differences accumulate to prevent successful interbreeding producing viable, fertile offspring; distinct species result. Allopatric = geographic barrier, e.g. Galápagos finches. Sympatric = without geographic separation, e.g. Howea palms.

Physical – waxy cuticle prevents entry, bark protects tissues, stomatal closure blocks openings, trichomes deter damage, protective tissue limits spread. Chemical – defensins are antimicrobial peptides; chitinaseslucanases attack fungal cell-wall components; phenolic and other antimicrobial chemicals inhibit microbes. EXAM: Know several examples and explain the mechanism; plants do not have animal B/T-antibody adaptive immunity.

Primary – first antigen exposure activates naïve B/T cells by clonal selection, expansion and differentiation, giving slower and generally weaker antibody response while generating memory cells. Secondary – later exposure activates antigen-specific memory cells, causing faster and stronger response and usually higher antibody concentrations. In graphs the secondary curve rises sooner and reaches a higher peak.

Relative dating – determines older/younger order without age in years; uses superposition/faunal succession. Absolute dating – estimates an age in years, including radiometric dating. Many fossils/sedimentary deposits lack suitable parent isotopes, so volcanic strata above and below are dated to bracket fossil age: lower layer older; upper layer younger, if undisturbed. Some organic remains can be directly dated using carbon-14.

Index fossil – widespread organism existing during a relatively short time interval; used to correlate and relatively date rock layers. Transitional fossil – mixture of ancestral and derived traits, supporting evolutionary change and relatedness. Index = Indicates age; Transitional = Shows transition. Transitional fossil is not necessarily direct ancestor.

Root – ancestral lineage at base. Branch – evolutionary lineage. Node – most recent common ancestor/divergence event. Tip – terminal taxon. Sister taxa – two groups sharing an immediate ancestral node. Clade – ancestor and ALL descendants. Outgroup – lineage outside focal group, helping root tree. Branch length only represents timeenetic change if calibrated. EXAM: Interpret trees and insert a putative species; constructing full trees from scratch is not required.

Superposition – in undisturbed sedimentary strata, lower layers are older than those above. Faunal succession – fossil organisms/assemblages appear in a recognisable chronological order, helping correlate and relatively date strata. Superposition relies on rock position; faunal succession on fossil assemblages.

B – Beta cells produce insulin; Type 1 diabetes is autoimmune destruction of these cells. I – Intron-free genes for A and B insulin chains separately. R – Restriction enzymes cut plasmids/insulin DNA at compatible sites. D – DNA ligase forms phosphodiester bonds to make recombinant plasmids. T – Transformation places plasmids into bacteria. A – Antibiotic marker selects transformed bacteria and reporter reveals recombinants. P – Protein expression as fusion proteins → purification → release and joining of A/B insulin chains.

Selectable marker gene – confers identifiable survival/property under selection, such as ampicillin-resistance enabling growth on ampicillin agar (shows plasmid uptake). Reporter gene – gives a measurable output for detecting insertion/expression, e.g. lacZ encodes β-galactosidase and disruption can yield white rather than blue colonies under correct conditions. Marker survival alone does NOT prove successful insertion.

Can produce human insulin with intended human amino-acid sequence, lowering risk of immune recognition of animal-sequence differences; microbial cultures support large-scale, controlled, reliable production/purity and reduce reliance on animal pancreas extraction. EXAM: Tie claims to sequence compatibility and manufacturing mechanism rather than saying "better".

Group of prokaryotic structural genes controlled together using shared regulatory DNA such as a promoter and operator, permitting coordinated transcription. Example: trp operon expresses tryptophan-biosynthetic enzymes when needed.

Consequences-based – maximise benefits/minimise harm, e.g. assess whether genetic engineering raises food security more than it creates risks. Duty/ rule-based – follow moral obligations despite consequences, e.g. obtain informed consent. Virtues-based – act with honesty, compassion and integrity, e.g. truthfully disclose unwelcome research results. Relevant ethical concepts: Integrity, Justice, Beneficence, Non-maleficence, Respect.

Mechanical – physically carries pathogen between hosts without pathogen developing or reproducing inside vector, e.g. fly carrying bacteria on body. Biological – pathogen reproduces or undergoes developmental stage in vector, e.g. mosquito and malaria parasite. Main distinction: whether a biological stage takes place inside vector.

The bicondylar/femoral angle describes inward orientation of the femur from hip to knee. A greater inward (valgus) angle brings knees/feet beneath the centre of mass, improving upright walking stability and efficiency compared with a relatively straight femur. Extremely large angles are not universally better; explain adaptation in comparative evolutionary context.

Cofactor – non-protein helper required by/assisting an enzyme; may be inorganic ion (e.g. Mg²⁺) or organic. Coenzyme – organic non-protein cofactor that often transfers electrons/hydrogen/chemical groups, e.g. NAD⁺/NADH, FAD/FADH₂, NADP⁺/NADPH or ATP. All coenzymes are cofactors, but not every cofactor is a coenzyme.

Emerging – newly recognised/newly occurring in a population or increasing in incidence/ geographical spread. Re-emerging – previously known disease that returns/increases after a period of reduced prevalence or control. A disease long known elsewhere can be emerging for a previously unexposed population. EXAM: Consider introduction of infectious diseases to Aboriginal/Torres Strait Islander peoples following European arrival.

Adaptive – specific antigen recognition by B/T receptors, clonal selection and expansion, and classical immunological memory; generally slower on first exposure and faster later. Innate – rapid, broad detection of conserved microbial patterns; barriers, phagocytes, NK cells, mast cells, complement; no corresponding classical antigen-specific B/T-cell memory. Three high-yield features: Specificity → Clonal selection → Memory.

Host – organism in/on which pathogen lives or reproduces. Reservoir – organism/population/environment where pathogen is normally maintained and from which infection spreads. Vector – living organism transporting pathogen between hosts. They can overlap; for example a mosquito is a malaria vector and host for part of the parasite life cycle.

Phosphodiester bonds form between adjacent nucleotides in the sugar-phosphate backbone; DNA polymerase adds nucleotides during synthesis and DNA ligase seals nicks. Hydrogen bonds form between complementary bases of different DNA strands; peptide bonds join amino acids into polypeptides.

1. Some transcription begins when repressor temporarily dissociates. 2. High charged tRNA-Trp allows ribosome to translate two leader Trp codons without pausing. 3. Terminator hairpin forms in the leader mRNA. 4. RNA polymerase terminates transcription prematurely. 5. Structural genes remain unexpressed, saving cellular resources.

PAMPs – pathogen-associated molecular patterns, conserved microbial molecular features. PRRs – pattern-recognition receptors on/in host cells that recognise microbial patterns and initiate innate immune responses. TLRs – Toll-like receptors, one family of PRRs. PAMP = pattern; PRR = recogniser; TLR = type of recogniser. Example: recognition of bacterial molecules triggers cytokine/inflammatory signalling.

Compare homologous amino acid sequences; fewer differences generally imply a more recent common ancestor, accounting for mutation rates and selection. Conserved proteins serve important functions and change slowly, enabling comparison even between distantly related species. Identical protein sequences do not guarantee identical DNA because multiple codons can encode one amino acid.

Tentatively proposed or inferred from currently available evidence without definitive confirmation. A putative Homo species is a proposed classification that may be revised when new fossilsenetic evidence emerge.

Coding DNA – encodes a protein amino-acid sequence. Non-coding DNA – not translated into protein (includes introns and regulatory sequences). Template/antisense strand – DNA strand read by RNA polymerase to produce complementary RNA. Coding/sense strand – same base order as RNA except DNA contains T where RNA has U. Example coding DNA ATG GCT TAA; template TAC CGA ATT; RNA AUG GCU UAA. Strand role depends on particular gene.

Simplified organisation: separately encoded trpR regulatory gene, then Promoter (P) → Operator (O) → Leader (trpL) → trpE, trpD, trpC, trpB, trpA structural genes. trpR encodes repressor; promoter binds RNA polymerase; operator binds activated repressor; leader supports attenuation; five structural genes encode enzymes for tryptophan synthesis. EXAM: Understand roles; specific structural-gene enzyme chemistry is not required.

Antibiotics can become less effective, requiring alternatives/combinations, increasing cost/treatment difficulty and allowing resistant populations to spread. Strategies: appropriate prescribing/antimicrobial stewardship, improved infection control, surveillance and new therapies. Antibiotics select for resistant variants rather than intentionally causing adaptive mutations.

Variation → Selection pressure → Differential survivaleproduction → Allele frequency change. Mutations or gene transfer create resistance in some bacteria; antibiotics kill/inhibit susceptible bacteria while resistant bacteria survive; resistant bacteria reproduce and spread the allele, so resistance allele frequency increases over generations. Horizontal transfer can occur by conjugation, transformation and transduction.

Take up recombinant DNA/plasmids to express therapeutic proteins, industrial enzymes and other biotechnology products; amplify plasmid DNA and investigate gene functions. General pathway: obtain suitable gene/plasmid → recombine → transform bacteria → select suitable transformants → culture/express. EXAM: Apply to unfamiliar cases, not just insulin.

Prepare suitable plant biomass → enzymatically hydrolyse starch/cellulose if necessary to fermentable sugars → anaerobically ferment sugars with yeast to produce ethanol + CO₂ → separate/purify ethanol (e.g. distillation). Remember P-H-F-S: Prepare, Hydrolyse, Ferment, Separate. EXAM: Understand biomass inputs, enzyme function, fermentation products; detailed industrial specifications not required.

Repression – tryptophan-bound active repressor binds operator and prevents transcription initiation (DO NOT START). Attenuation – transcription initiates but leader mRNA forms a terminator hairpin, stopping transcription prematurely before structural genes (STOP EARLY). Both conserve energyesources when tryptophan is abundant.

PCR-amplify target locus → load sample, control and DNA ladder into agarose gel → apply electric field; negatively charged DNA moves to positive electrode and smaller fragments travel further → compare band sizes to predicted editednedited fragments. E.g. deleting 200 bp from a 1,000-bp amplicon gives an expected 800-bp band. Limitation: a small mutation may not visibly change fragment size; sequencing or restriction-based assays may be needed.

Structural genes encode functional products (such as tryptophan-biosynthesis enzymes). Regulatory genes encode products controlling gene expression (such as the trp repressor protein). A regulatory gene is DNA; a repressor is its protein product.

Y-shaped quaternary protein of two identical heavy and two identical light polypeptide chains, held partly by disulfide bonds. Two variable regions at arm tips form TWO antigen-binding sites specific to the same antigen epitope. Constant regions form much of the remainder and are involved in effector functions. Antigen recognition depends on complementary shape/chemistry.

Allows bacteria to regulate production of enzymes required for synthesising the amino acid tryptophan, conserving resources when tryptophan is plentiful. trpE–trpA structural genes encode biosynthetic enzymes. Low Trp generally permits greater expression; high Trp promotes repression and attenuation. EXAM: Know overall function, not the exact reaction catalysed by each named enzyme.

Repressor binding to the operator is not permanent; some basal transcription starts when it transiently dissociates, even with high tryptophan. Attenuation acts as additional fine control: when charged tRNA-Trp is readily available, ribosome translates leader quickly, terminator hairpin forms and transcription ends before structural genes, preventing wasteful enzyme synthesis.

Found free in the cytosol, incorporated into proteins and attached to tRNA-Trp during translation; animals also obtain it from dietary protein. Free intracellular tryptophan acts as co-repressor by binding repressor protein. Charged tRNA-Trp allows leader peptide translation through two adjacent Trp codons without pausing, supporting attenuation. EXAM: Know the difference between free tryptophan and availability of charged tRNA.

Complementary GC-rich sections help stabilise RNA terminator hairpin; downstream U-rich sequences are commonly associated with intrinsic transcription termination. In trp attenuation, leader mRNA hairpin causes premature transcription termination. EXAM: Exact sequence and numbered stem-loop pairing are not required.

20 standard amino acids are commonly used in protein synthesis. Nine are essential in the human diet: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine. EXAM: VCAA requires amino acids as protein monomers, but memorising all nine essential amino acids is not specified Unit 3/4 content.

Bacterial – cell wall (where present), membrane, cytoplasm, nucleoid DNA, plasmids, ribosomes and possible flagellum. Eukaryotic – plasma membrane, nucleus, mitochondria, ribosomes, ER and Golgi; plant cells may have chloroplasts, cellulose wall and large vacuole. Bacteria lack membrane-bound organelles and usually have circular DNA; eukaryotes possess nuclei/organelles.

Label – identify/name the relevant component on a diagram (e.g. “mitochondrion”). Annotate – name it AND add a relevant explanation (e.g. “mitochondrion – Krebs cycle occurs in matrix, ETC on inner membrane”). A name alone may not earn marks when annotation is required.

Find the most recent common ancestor (MRCA). Two species sharing a more recent node are more closely related than species whose shared ancestor is older. Tip proximity on the page, left–right order and rotation of branches do NOT determine relatedness. Branch lengths only indicate timeenetic change if calibrated. If X and Y share a node and Z branched earlier, X is closer to Y than Z.