Qualifications Scotland (SQA) National 5 Biology Past Papers 2026

Section 1 (objective test) + Section 2 (structured and extended response)

Duration: 2 hours 30 minutes

Researched biological investigation

Duration: 1 hour 30 minutes (report stage, under supervised conditions)

Experimental skills — validity, reliability, controls, and controlled variables

All three course reports identify this as a persistent weakness. Candidates confuse validity (the test is fair) with reliability (the results can be trusted), and routinely fail to distinguish a control experiment (same setup without the key variable) from a controlled variable (a factor kept constant). In 2025, nearly all candidates failed to suggest why results should be calculated as a percentage change, and most failed to give a conclusion rather than restating results.

Question Paper, Assignment

Enzyme structure and specificity — active site, substrate binding, and denaturation

In 2023, many candidates did not mention 'active site' when describing substrate specificity of pepsin. In 2024, most candidates could not explain how results showed an enzyme was required. In 2025, most candidates could not explain why invertase would not speed up a different reaction. The complete explanation chain — specific active site shape, complementary substrate, no reaction without the correct fit — is required for full marks.

Question Paper

Osmosis and membrane transport — specifying the substance and direction of movement

In 2023, most candidates did not mention that membrane proteins were involved in active transport. In 2025, many candidates gave a generic definition of diffusion instead of explaining why potassium moved out of seaweed cells, and many could not name active transport. Applying transport processes to specific contexts is consistently more difficult than recalling definitions.

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Photosynthesis — both stages, especially carbon fixation and products of glucose

In 2023, many candidates were unable to describe how sugar is produced in the second stage of photosynthesis. In 2024, many could not name cellulose as a product of glucose conversion, with several incorrectly writing 'glucose' as the answer. In 2025, many correctly stated that glucose breaks down into pyruvate but could not describe subsequent events in respiration.

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Genetics — allele terminology, homozygous/heterozygous reasoning, and Punnett squares

In 2023, many candidates found the chromosome complement question difficult. In 2025, many could not state the correct number of offspring with short coats in a genetic cross, and many explained homozygosity using 'gene' instead of 'allele'. Precise use of genetic terminology is essential for full marks.

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Nervous system — synapse transmission, reflex definition, and receptor function

In 2024, many candidates were unable to state how messages are transferred across the synapse, and many could not give the definition of a reflex. In 2025, most candidates could not demonstrate knowledge of receptors in the nervous system, and many could not give the function of the medulla.

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Assignment analysis and conclusion — comparing data and drawing valid conclusions

In both 2024 and 2025, many candidates failed to give a valid comparison between their experimental data and the literature data in their analysis. In 2025, many did not draw a valid conclusion relating to their aim and instead restated their own results. This recurring failure means candidates lose marks in Sections 5 and 6 every year.

Assignment

Application of knowledge to unfamiliar contexts

All three course reports state that candidates do not cope well with questions in new and unfamiliar situations. In 2024, most candidates could not suggest a selection pressure that led to birds developing different beak shapes. In 2025, most could not explain how natural selection occurs. Questions that require applying biological knowledge to novel scenarios are consistently more poorly answered than recall questions.

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