HEREDITY
The difference between a genotype and a phenotype.
Genotype = genetic makeup; phenotype = observable traits.
What is a mutagen? Give one example.
Mutagen = agent causing mutations (e.g. UV light).
Name one physical barrier in the human body that prevents pathogen entry.
Skin, mucus, tears, stomach acid.
What is one example of an environmental disease?
Example: lung cancer from smoking.
What is the difference between accuracy and reliability?
Accuracy = closeness to true value. Reliability = consistency of results.
What is the expected phenotypic ratio of offspring in a heterozygous monohybrid cross?
3:1 (dominant:recessive).
What is the difference between point mutation and chromosomal mutation?
Point = single base change. Chromosomal = whole sections.
What is the difference between antigen and antibody?
Antigen = foreign molecule. Antibody = protein that binds antigen.
Explain how lifestyle factors can contribute to cardiovascular disease.
Diet, smoking, inactivity → heart disease.
A student records the following data: 3.2 cm, 3.4 cm, 3.1 cm. Calculate the mean.
Mean = 3.23 cm.
Name one advantage and one disadvantage of asexual reproduction.
Advantage = rapid, many offspring. Disadvantage = no variation.
Explain how selective breeding reduces genetic variation in a population.
Reduces variation by narrowing gene pool.
Outline the steps of the inflammatory response.
Injury → histamine → vasodilation → phagocytes → swelling/redness.
In the blood glucose negative feedback loop, what is the control centre and what is its role?
The pancreas detects blood glucose changes and releases insulin (if high) or glucagon (if low) to restore normal levels.
Identify the independent variable in this experiment: “The effect of light intensity on the rate of photosynthesis.”
Independent variable = light intensity.
Explain how crossing over during meiosis contributes to genetic variation.
Crossing over swaps DNA → new allele combinations.
Describe the process used in recombinant DNA technology.
Recombinant DNA = insert foreign gene into plasmid, transfer to organism.
Explain how vaccination protects individuals and populations.
Vaccines produce memory cells → herd immunity.
Describe the roles of filtration and reabsorption in the kidney nephron.
Filtration: In glomerulus, small molecules (water, urea, salts, glucose) forced into Bowman’s capsule.
Reabsorption: Useful substances (glucose, water, ions) reabsorbed into blood in tubules.
If Miss Denniss wasn't a teacher, what would she be instead?
Either a midwife, cafe owner or florist.
A woman who is a carrier for haemophilia (XᴴXʰ) has children with a normal male (XᴴY).
What is the probability that a son has haemophilia?
50% chance son has haemophilia.
What enzyme is used in the CRISPR system, and what is its role?
Cas9 enzyme – acts as “molecular scissors” to cut DNA at a specific location guided by RNA.
What cells link the innate and adaptive immune systems and how do they function?
APCs (e.g. macrophages) engulf pathogens → display antigens on MHC → activate T helper cells → trigger adaptive response
What type of lens is used to correct myopia and hyperopia?
Myopia (short-sightedness): corrected with a concave (diverging) lens.
Hyperopia (long-sightedness): corrected with a convex (converging) lens
What is Miss Denniss's favourite Module from HSC Biology?
Module 5 or 7.