Where the 260 A2 marks sit
The A2 year is assessed across three papers: A2 1 Physiology, Coordination and Control, and Ecosystems (100 marks, 135 minutes), A2 2 Biochemistry, Genetics and Evolutionary Trends (100 marks, 135 minutes), and A2 3 Practical Skills in Biology (60 marks, 75 minutes). That is close to a mark a minute on the two theory papers and a little faster on the practical paper, so a nine-mark structured question should not run past nine or ten minutes. A2 1 and A2 2 each end with an 18-mark extended prose question, split into a smaller and a larger part, assessed for quality of written communication. Do not leave that question for the last five minutes.
The recurring cost: units, not understanding
The most common reason marks are lost across A2 1 and A2 2 is not a gap in biological knowledge, it is an unconverted or misapplied unit. Haemocytometer counts need the depth of the counting chamber and any dilution factor built into the final concentration, not just the raw cell count. Conduction velocity and axon measurements need millimetres and metres kept consistent through the whole calculation, not switched partway through. Before you write a final numerical answer, check the unit the question asks for, and check every intermediate step used the same unit system.
Definitions that get swapped under pressure
A handful of paired terms account for a disproportionate share of lost marks because they sound similar but mean different things. Allele frequency, written p or q, is not the same number as genotype frequency, p squared or q squared, in Hardy-Weinberg questions, and mixing the two invalidates the whole calculation. Dominance describes interaction between alleles of the same gene; epistasis describes interaction between different genes, and examiners report these being used interchangeably. When you explain competitive inhibition, name the mechanism precisely: the inhibitor binds the active site because it is a similar shape to the substrate, it does not simply block the enzyme in general terms.
The extended prose question: coverage over elaboration
The 18-mark Section B question on each theory paper is marked against a threshold of indicative content: a response needs to cover a wide spread of distinct, relevant points to reach the top band, not develop one or two points at great length. Plan your answer as a list of the specific mechanisms, structures or examples the question is actually asking you to bring in, in the scenario given, before you start writing continuous prose. A generic, well-written answer that does not engage with the specific context in the question caps itself below the top band regardless of how fluent it reads.
CCEA conventions
A2 papers carry synoptic assessment: they draw on AS content as well as A2 content and expect you to connect ideas across the specification rather than answer as if each topic sat in isolation. Quality of written communication applies specifically to the Section B extended response and rewards legible, accurate, well-organised writing that uses specialist terminology, not length. When a statistical test gives you a probability, state the comparison to the 0.05 threshold explicitly and say what that means for the null hypothesis, rather than leaving the number to speak for itself.
The week before
Work back through three years of A2 1 and A2 2 numerical questions and redo every unit conversion explicitly, writing the units at each step rather than only at the final answer. For the Section B questions, take three past titles and write a bullet list of every distinct point you would cover before attempting a full response, then check that list against how many separate ideas it contains rather than how long any one paragraph would be. In A2 3, rehearse reading the statistics sheet provided in the exam before you start the paper, so you are not searching for a formula under time pressure.