Life processes at the cellular level

Practice

Recall it first, then use it — testing yourself builds the memory, where rereading the notes above only feels easier.

Recall and application shuffled together — you have to work out what each item wants before you can answer it, which is the part the exam actually tests. Both kinds feed the same spacing schedule, so anything you miss comes back sooner.

Say the answer out loud before flipping — that attempt is where the learning happens, even when you get it wrong.

Exam-style only. Instant feedback, shuffled each attempt, best score saved on this device.

What actually comes up

Three "discuss" questions every year, each opening with a diagram-labelling part (worth the Achieved marks) before a full extended-writing discussion (worth Merit and Excellence). The question pool draws from photosynthesis, respiration, enzymes, transport, and cell division/mitosis — not always the same three, so all five areas need real depth.

Across 4 years

The pattern — what to prepare

The 2025 paper ↗ Marking schedule ↗

Question One — Photosynthesis in different environments

A NZ terrestrial plant (climbing clubmoss) and an aquatic plant (water milfoil), where CO₂ can be limiting.

• achieved Describes the process of photosynthesis, the light-dependent phase (thylakoid) and light-independent phase (stroma), the daylight change in light intensity and temperature, why CO₂ is needed, diffusion, a limiting factor, and chlorophyll's role. Achieved
• merit Explains the light-dependent and light-independent phases, how rate changes with light intensity and temperature, and why CO₂ is a limiting factor in aquatic plants but not terrestrial ones. Merit
• excellence Provides detailed discussion of the key phases and locations linked to the context, how rate changes from a COMBINATION of factors, and why limited CO₂ results in a lower rate of aquatic photosynthesis. Excellence

Question Two — Cell respiration

A cheetah sprinting at up to 112 km/h in short bursts to catch prey.

• a Label the outer membrane, inner membrane, matrix, and crista on a mitochondrion diagram. Achieved
• b (achieved) Describes aerobic and anaerobic respiration, where each occurs (mitochondria vs cytoplasm), when each is used, and one advantage and one disadvantage of each. Achieved
• b (merit) Explains aerobic and anaerobic respiration with their advantages and disadvantages, the process and location of each, and mitochondrial structure/function links. Merit
• b (excellence) Provides detailed discussion of how each respiration type's advantages/disadvantages directly relate to the cheetah, and why it needs BOTH systems to function effectively in its lifestyle. Excellence

Question Three — Enzyme function and temperature

General questions on enzyme structure and temperature sensitivity.

• achieved Describes enzyme structure and function (catalysts, active site), tolerance limits, denaturing at high temperature, optimal temperature, reduced rate at low temperature, and the lock-and-key or induced-fit model. Achieved
• merit Explains how enzyme structure enables function (lock-and-key or induced fit), why high/low temperature affects activity, enzyme-substrate complex formation, and the role of enzymes in a biological process. Merit
• excellence Provides detailed discussion of function related to structure and temperature sensitivity, the mechanism behind high/low temperature effects, and the impact of enzyme activity on an organism's overall cellular activity rate. Excellence

The 2024 paper ↗ Marking schedule ↗

Question One — Cellular respiration

The Brazilian wandering spider moves at up to 50 cm/s when attacking prey or escaping predators.

• a Write the word or chemical equation for aerobic respiration. Achieved
• b (achieved) Describes aerobic and anaerobic respiration (word/symbol equation), where each occurs, and one advantage and one disadvantage of each. Achieved
• b (merit) Explains anaerobic respiration linked to the absence of O₂ and its location, with an advantage AND disadvantage of each type, and why both systems are needed. Merit
• b (excellence) Discusses where and when anaerobic and aerobic respiration occur, linking to fast attack/escape versus steady movement, and the advantages/disadvantages of each to the spider specifically. Excellence

Question Two — Photosynthesis

"Shade leaves" are up to five times more efficient than "sun leaves" at the same light level, but lose water faster, and have larger/more chloroplasts.

• a Label the key parts of a chloroplast diagram. Achieved
• b (achieved) Describes the process of photosynthesis, the light-dependent and light-independent reactions, their locations, the light-intensity difference between sun and shade leaves, and stomata function. Achieved
• b (merit) Explains the light-dependent and light-independent phases and their locations, why sun leaves have fewer/smaller chloroplasts and shade leaves more/larger ones, and how/why water loss differs. Merit
• b (excellence) Discusses the key phases of photosynthesis and why light availability matters, comparing chloroplast number/size and water-loss rates between sun and shade leaves. Excellence

Question Three — Cell division

Cells undergo a growth-then-division cycle in both plants and animals.

• achieved Describes diffusion as movement down a concentration gradient, as a passive process across a semi-permeable membrane, how SA:V ratio changes with growth, and gives an example of a high cell-division rate. Achieved
• merit Explains the purpose of diffusion, why SA:V ratio changes as a cell grows and affects material movement, and why cells must divide once they reach a certain size. Merit
• excellence Discusses the linked chain from SA:V ratio to diffusion effectiveness to material transport, with appropriate animal and plant examples of high cell-division rates supporting the discussion. Excellence

The 2023 paper ↗ Marking schedule ↗

Question One — Photosynthesis and enzymes

Photosynthesis is enzyme-controlled, so temperature and substrate concentration both affect its rate.

• a Write the complete word equation for photosynthesis. Achieved
• b (achieved) Describes enzymes as biological catalysts, identifies CO₂/water as reactants, and states that more/less reactants or high/low temperature will speed up, slow, or stop photosynthesis. Achieved
• b (merit) Explains that denaturing changes the enzyme's active site shape, high heat breaks bonds permanently, increased substrate concentration speeds reactions via more enzyme-substrate complexes, and low temperature reduces successful collisions without permanent damage. Merit
• b (excellence) Discusses the effect of both very high and very low temperatures on enzymes and photosynthesis, and the effect of CO₂ and water concentration on the light-dependent/independent reactions together. Excellence

Question Two — Transport of materials

Sulphate ions enter plant root cells by both facilitated diffusion and active transport; a graph compares uptake by each method over time.

• achieved Describes active transport (energy, against the gradient) and facilitated diffusion (passive, with the gradient), their difference, an example of each, and one similarity, referencing the graph. Achieved
• merit Explains how active transport uses a protein pump and why it occurs for sulphate ions, why facilitated diffusion needs a protein channel for ions that can't cross the bilayer freely, and reads the graph to explain the uptake difference. Merit
• excellence Discusses, with reference to the graph, why sulphate uptake continues via active transport but stops at equilibrium via facilitated diffusion. Excellence

Question Three — Mitosis and DNA replication

A butterfly's life cycle illustrates when and why cells divide.

• achieved Describes DNA replication occurring before mitosis, unzipping and adding complementary nucleotides, semi-conservative replication involving enzymes, and that mitosis makes identical cells for growth/repair. Achieved
• merit Explains DNA replication using the parent strand as template, base pairing (A-T, C-G), and enzyme involvement, plus why cells must retain a small size (SA:V) and why mitosis continues for repair once growth stops. Merit
• excellence Discusses the need for each cell to carry correct DNA instructions AND retain a small SA:V for efficient transport, with life-stage-specific examples of mitosis for growth and for repair. Excellence

The 2022 paper ↗ Marking schedule ↗

Question One — Photosynthesis

A native plant requires specific reactants to start photosynthesis; the chloroplast's outer membrane, inner membrane, stroma, thylakoid membrane and grana are shown in a diagram.

• a Describe the reactants required for photosynthesis, and how they enter the plant. Achieved
• b Discuss how specific reactants in the light-dependent and light-independent reactions affect the amounts of photosynthesis products, describing the function of TWO named chloroplast structures, explaining how their structure supports that function, and discussing how the structures work together. Excellence

Question Two — Enzymes

Pond water conditions (pH, pollutants affecting cofactors) change throughout the day and year; a graph shows Elodea (pondweed) enzyme reaction rate against pH from 2 to 14.

• a Discuss the effects of pH and co-factors on enzyme activity in Elodea plants, referring to the graph — describing enzyme function and structure, explaining how co-factors affect enzyme activity, and discussing how and why pH affects it. Excellence

Question Three — Cellular respiration

Mosquito larvae absorb oxygen through a breathing tube at the surface, or dissolved oxygen when submerged; heart rate (a proxy for respiration rate) is recorded at 0%, 25%, 50%, 75% and 100% dissolved oxygen saturation, falling from 120 bpm to 20 bpm but never reaching zero even at 0% oxygen.

• a Describe the purpose of cellular respiration. Achieved
• b Discuss the heart-rate observations in relation to aerobic and anaerobic respiration, referring to the data table — describing where each type of respiration occurs, explaining the materials required and products of each, and elaborating on the possible effects on the larvae of 0% oxygen for more than a few hours. Excellence

Grades above are read from each year's own Achievement/Merit/Excellence evidence, condensed to the actual task — the schedules also grade holistically per question on a 0–8 scale, not a fixed mark per bullet.

Past exams & resources

⏱ Timed opens the paper and starts a countdown matching the exam length. Official NZQA PDFs. If a link 404s, that year’s paper may sit under a slightly different code: browse the NZQA subject page.