Qualifications Scotland (SQA) Advanced Higher Biology Past Papers 2026

Structured + extended-response

Duration: 3 hours

Researched investigation

Duration: Coursework — externally assessed

Applying knowledge to unfamiliar experimental contexts

The single most consistent differentiator across all three years. Candidates can recall mandatory knowledge but struggle to use it when it is embedded in an unfamiliar scenario or novel organism. Questions about indicator species, bat wing development, pine marten ecology, and selective sweeps all exposed this weakness.

Experimental design — confounding variables and controls

Candidates know that controls are needed but cannot articulate why a specific control is required or how a specific confounding variable compromises validity. Project evaluation and structured question marks on experimental design are both affected.

Signal transduction — phosphorylation cascades and second messengers

In 2024, few candidates showed good understanding of kinases operating in series within a cascade (Q5(b)), and few correctly described Glut-4 recruitment and its failure in diabetes (Q5(c)). The rhodopsin pathway amplification values were also poorly known.

Cell cycle regulation — CDKs, cyclins, p53 and retinoblastoma protein

In 2024 (Q13B), candidates focused too narrowly on the G1 checkpoint and confused transcription with translation when describing retinoblastoma protein mechanism. Understanding that CDKs operate throughout the cycle, not just at G1, was weak.

Protein structure at AH level — tertiary interactions and membrane protein behaviour

In 2024 (Q3(a)) only some candidates described hydrophobic interactions holding integral membrane proteins; in 2025 (Q3(a)) many repeated the question stem rather than explaining how disrupted R-group interactions lead to unfolding.

Population genetics — Hardy–Weinberg and evolutionary mechanisms

In 2023 (Q14) only some candidates applied Hardy–Weinberg correctly. In 2025, few candidates fully applied natural selection to the concept of a selective sweep (Q10(a)), and the phylogenetic tree question (Q11) was missed by most candidates.

Project discussion — evaluation of results and statistical interpretation

Consistently the hardest project section. Candidates state trends but do not analyse variation between repeats and replicates, do not address methodological limitations critically, and misuse or misinterpret statistical tests.

Behaviour and ecology — applying terminology (anthropomorphism, ethogram, indicator species)

In 2025 (Q8(a)), candidates who missed the mark did not explain why anthropomorphism must be avoided, merely defined it. In 2023 (Q8(b)), the terms 'favoured' and 'susceptible' rarely appeared in responses about indicator species.