Genetics
What is the genetic makeup of an individual called?
Genotype
What is a pathogen?
An organism/agent capable of causing disease.
What is natural selection?
Differential survival and reproduction of individuals due to heritable variation.
What does PCR stand for?
Polymerase Chain Reaction.
What is the independent variable?
The variable deliberately changed by the researcher.
What is an adaptation?
A characteristic that increases an organism's ability to survive/reproduce in its environment
What does homeostasis mean?
Maintaining relatively stable internal conditions.
What is the role of DNA in a cell?
DNA stores the genetic information that codes for proteins and determines inherited characteristics.
What is thermoregulation?
The maintenance of a relatively stable internal body temperature despite changes in environmental temperature.
What is the only continent with no native ants?
Antartica
Who is my favourite student in ATAR Biology?
Peta ♥
Two roan horses showing incomplete dominance are crossed. What proportion of offspring would be expected to be roan?
50%
What is a zoonotic disease?
A disease that can be transmitted between different vertebrate species.
What is genetic drift?
Random changes in allele frequencies, particularly significant in small populations.
What is the purpose of PCR?
To amplify DNA, producing many copies of a target sequence.
What is the dependent variable?
The variable measured in response to the independent variable.
What is a structural adaptation?
A physical feature of an organism.
What type of feedback mechanism is primarily responsible for maintaining homeostasis?
Negative feedback
What is the difference between mitosis and meiosis?
Mitosis: produces 2 genetically identical diploid cells for growth, repair and asexual reproduction.
Meiosis: produces 4 genetically different haploid gametes for sexual reproduction.
Why do organisms need to maintain a relatively stable internal temperature?
To maintain the conditions required for enzyme activity and metabolic reactions to occur effectively.
Which Australian animal is known for laying eggs despite being a mammal?
Platypus
What food cuisine did Lucas want to leave the zoo to purchase?
Kebabs
Two healthy carrier dogs for an autosomal recessive condition are crossed. What are the expected genotype proportions?
25% homozygous dominant, 50% heterozygous, 25% homozygous recessive
Why does high vaccination coverage reduce disease transmission?
It reduces the number of susceptible hosts, limiting transmission through herd immunity.
What type of speciation occurs when populations become geographically isolated?
Allopatric speciation
What is recombinant DNA?
DNA formed by combining genetic material from different sources.
What is the purpose of a control group?
Provides a comparison against which the effect of the independent variable can be assessed.
Why are stomata often sunken in xerophytes?
They reduce exposure to moving/dry air and therefore reduce water loss.
Put these in order: effector, stimulus, receptor, response, control centre.
Stimulus → receptor → control centre → effector → response
Explain semi-conservative DNA replication.
The DNA double helix unwinds and separates into two strands. Each original strand acts as a template for a new complementary strand. Each resulting DNA molecule contains one original strand and one newly synthesised strand.
Explain how an elongated Loop of Henle helps an animal conserve water.
A longer Loop of Henle allows a stronger osmotic gradient to develop in the kidney medulla. This allows more water to be reabsorbed from the filtrate, producing more concentrated urine and reducing water loss.
What is the longest-running animated TV series?
The Simpsons
How many students were enrolled in Biology in 2025?
16
A trait is autosomal recessive. An unaffected individual has an affected parent. What must their genotype be?
Heterozygous carrier
Explain how antibiotic resistance can develop in a bacterial population.
1. Variation exists
2. antibiotics kill susceptible bacteria
3. resistant bacteria survive
4. reproduce
5. resistance allele becomes more common.
A dam separates two frog populations. Over thousands of generations they become reproductively isolated. Explain how this can lead to speciation
1. Reduced gene flow
2. populations accumulate different mutations/selection/drift
3. genetic divergence
4. reproductive isolation
5. separate species.
Explain how gene flow from a herbicide-resistant GM crop could produce a "super weed.
Resistance gene transfers to weeds → weeds gain resistance → herbicide kills susceptible weeds → resistant weeds survive and reproduce.
What is the difference between reliability and validity?
Reliability: consistency/repeatability.
Validity: whether the investigation actually measures what it intends to measure.
Why does a thick waxy cuticle help desert plants?
It reduces evaporation of water from the leaf surface
Explain evaporative cooling.
Energy is required for water molecules to evaporate; higher-energy molecules leave the surface, reducing the average kinetic energy/temperature of the remaining tissue.
Describe the process of transcription.
DNA unwinds at the gene. One DNA strand acts as a template, and RNA polymerase builds a complementary mRNA strand. The mRNA then leaves the nucleus and moves to a ribosome.
Explain how evaporative cooling reduces body temperature.
When water evaporates from a body surface, it requires energy. Higher-energy water molecules leave the surface, reducing the average kinetic energy of the remaining molecules and therefore lowering body temperature
Which Australian city is known as the City of Churches?
Adelaide
Which two students got the highest mark in an assessment after going to homework club in 2025?
Lucas and Miggy
Explain how independent assortment produces genetic variation.
Homologous chromosome pairs independently orient during meiosis I, producing different combinations of maternal and paternal chromosomes in gametes.
Explain the lifecycle of a virus.
Attachment → entry → replication of viral genetic material → synthesis/assembly of viral components → release.
A DNA comparison shows Species A and B are 96% similar. Species A and D are 72% similar. What does this suggest?
A and B are more closely related and share a more recent common ancestor.
What is a transgenic organism?
An organism containing genetic material introduced from another organism, typically another species.
Give two ways to increase reliability.
Repeat trials, calculate a mean, increase sample size.
Explain why marram grass leaves curl inward.
They create a more enclosed environment around the stomata, reducing air movement and therefore reducing transpiration.
Why does an elongated Loop of Henle help an animal survive in an arid environment?
It establishes a stronger medullary osmotic gradient, allowing more water to be reabsorbed and producing concentrated urine.
Describe the process of translation.
mRNA attaches to a ribosome. The ribosome reads the mRNA codons, while tRNA molecules bring the corresponding amino acids. The amino acids are joined by peptide bonds to form a polypeptide, which folds into a functional protein.
Compare endotherms and ectotherms, including how each regulates body temperature
Endotherms: generate most of their body heat internally through metabolic processes and can maintain a relatively stable body temperature.
Ectotherms: rely more heavily on heat from the external environment and regulate body temperature largely through behavioural and physiological responses.
Which football club plays at Old Trafford?
Manchester United
What type of animal did I brutally murder that kept me awake at night?
Frog
In sickle-cell anaemia, a DNA base sequence changes from CTC to CAC. Explain how this can alter the protein produced.
Point mutation → altered mRNA codon → different amino acid → altered polypeptide structure/function
Explain how human activity could increase the spread of a vector-borne disease.
any activity that links to:
vector abundance/distribution/contact with humans
increased transmission
increased infections.
Why are transitional fossils important evidence for evolution?
They can show combinations of ancestral and derived characteristics, providing evidence for evolutionary transitions.
Explain how widespread Bt cotton could select for pesticide-resistant insects.
Existing genetic variation → susceptible insects die → resistant individuals survive → reproduce → resistance allele increases in frequency over generations.
Students investigate light intensity and water loss. What additional variable should they control that could affect transpiration?
Temperature, humidity, wind speed, plant species/size
Compare the adaptations of a halophyte and a xerophyte to their respective environments.
Halophytes are adapted to salty environments, have salt-excreting glands, salt storage tissues, or other mechanisms to remove/tolerate excess salt
Xerophytes are adapted to dry environments, have thick waxy cuticles, sunken stomata, reduced leaves and extensive root systems to reduce water loss and maximise water uptake
Comparison: Both reduce the challenges of water availability, but halophytes primarily need to cope with high salt concentrations, whereas xerophytes primarily need to cope with low water availability.
Explain how negative feedback maintains homeostasis in a complete stimulus-response system.
Stimulus causes deviation → receptor detects change → control centre processes information → effector responds → response counteracts original change → condition moves toward set point.
Explain how a mutation in DNA can ultimately affect the phenotype of an organism.
A mutation changes the DNA base sequence, which may alter an mRNA codon and therefore the amino acid sequence of a protein. This can change the protein's structure or function, potentially altering a cell process and ultimately producing a different phenotype.
Explain how structural, behavioural and physiological adaptations can work together to allow an organism to survive in an extreme environment.
A structural adaptation is a physical feature that assists survival, while a behavioural adaptation involves an action or behaviour and a physiological adaptation involves an internal functional process.
Together, these adaptations can reduce environmental stress and maintain homeostasis. For example, an animal in a cold environment could have insulating body structures, seek shelter behaviourally and increase metabolic heat production physiologically.
What is the world's largest desert?
Antartica
What word did Luka use that described Room 3?
Eery