Genetic Variation
Properties of Materials
Sun, Moon and Earth
Energy Concepts
100
What process produces gametes (sperm and eggs) in sexually reproducing organisms?
Meiosis
100
What is the structure of an ionic substance?
A 3D lattice
100
What causes the apparent movement of the Sun across the sky each day?
Earth’s rotation on its axis.
100
What is the difference between kinetic and potential energy?
Kinetic = energy of motion; potential = stored energy due to height of an object.
200
What is the difference between genotype and phenotype?
Genotype is the combination of alleles for a particular gene, phenotype is the physical trait or expression of those genes.
200
Why do metals conduct electricity but covalent molecular substances usually don’t?
Metals have delocalised electrons; covalent molecular substances have no free charges.
200
Why are tides higher during full and new moons?
Gravitational forces from the Sun and Moon align, producing spring tides.
200
A 10 kg object is lifted 2 m. Calculate its potential energy gain.
Ep = mgh = 10 x 10 x 2 = 200J
300
When is a mutation inheritable, when is it not?
Mutations that happen during meiosis in gametes (reproductive cells) can be passed on to offspring, mutations in body cells (somatic cells) cannot be passed on to offspring.
300
Why is an alloy stronger than a pure metal?
Because it has atoms of different sizes so they can't slide past each other like they can in a metal with all the same sized atoms.
300
Explain why the Moon appears to go through phases over a month.
As the Moon orbits Earth, we see different portions of its sunlit half.
300
Why might a falling object not reach its maximum velocity if energy is conserved?
Because, not all of the energy will turn into kinetic energy, some of it will be lost to heat and sound energy due to friction/air resistance.
400
How can gene tracking and DNA sequencing help breeding programmes aimed at conservation for a species?
- Identifying the most genetically different individuals to breed together
- Ensuring there is no inbreeding
400
Explain why some substances dissolve in water while others do not.
Water is a polar solvent, so it dissolves polar or ionic substances because the water molecules attract and separate the charged particles. Non-polar substances (like oils) don’t dissolve because there is no attraction between the molecules and water.
400
Describe what causes a King tide.
A king tide is the highest high tide of the year, occurring when the gravitational pulls of the sun and moon align during a new or full moon and the moon is at its closest point to Earth (perigee)
400
What are the three different types of heat transfer? Give a brief description of them each.
Radiation, Convection, Conduction
500
Discuss how genetic bottlenecks can reduce variation and affect a species’ long-term survival.
A population bottleneck reduces gene pool diversity, making it less able to adapt to future environmental changes or disease.
500
Describe how the properties of covalent network substances differ from those of metallic and molecular substances, and explain why.
Covalent network solids have very strong bonds throughout → high melting points and hardness, unlike metals (mobile electrons) or molecules (weak forces).
500
Why does Dunedin have more variation in daylight than Auckland over the course of the year?
Earth’s tilt means Dunedin’s angle to the Sun changes more through the year, giving bigger daylength variation than nearer the equator (Auckland).
500
A 60 W bulb runs for 5 minutes. Calculate the total energy used.
E = Pt = 60×300 = 18,000 J