How to get an A* in IGCSE Biology 0610

Only Extended candidates can get an A*. Extended students take Paper 2 (40 multiple-choice questions, 45 minutes, 30%), Paper 4 (theory, 80 marks, 1 hour 15 minutes, 50%) and a practical paper worth 20%, usually Paper 6, the Alternative to Practical (40 marks, 1 hour).

Paper 4 is half your grade, so structured written answers matter most. Paper 6 is worth a fifth and is very learnable: the same experiments and skills come up again and again.

Mark schemes look for specific words. A nearly-right word often scores zero.

• Enzymes are denatured, never killed. The active site is complementary to the substrate, not "the same shape".
• Diffusion is the net movement of particles from a higher to a lower concentration, as a result of their random movement.
• Osmosis is about water moving across a partially permeable membrane. Say which way the water moves.
• Respiration releases energy. Energy is never "produced" or "made".
• Genotype is the letters (Bb); phenotype is what you see (black fur). Gametes carry one allele.

Tip: Keep a "key words" list for each topic and test yourself on it weekly. Most lost marks are about wording, not ideas.

Free lessons: Enzymes · Diffusion · Osmosis

Describe means say what happens or what the data shows. Explain means say why, using biology. Many students explain when asked to describe, or describe when asked to explain, and lose marks either way.

Tip: For "explain", link cause to effect with "because" or "so": "the active site changes shape, so the substrate no longer fits".

More than a third of the marks on Papers 2 and 4 test handling information, so reading tables and graphs well is a big deal.

• Describing a graph: give the trend and quote numbers with units read from the graph.
• Percentage change: divide the change by the starting value, then multiply by 100. Keep the minus sign for a decrease.
• Rate = amount ÷ time. Never divide time by the amount.
• Magnification = image size ÷ actual size. Put both in the same unit first (1 mm = 1000 μm).

Free lessons: Reading graphs and tables in biology · Biology maths: percentages, rates and means · Size of specimens

Paper 6 tests experimental skills only. You will plan, record, process and evaluate experiments such as food tests, enzyme rates, osmosis in potato, photosynthesis in pondweed and drawing specimens.

• Table headings carry units after a slash: time / s. No units in the table body.
• Graphs: independent variable on the x-axis, both axes labelled with units, points plotted accurately.
• Drawings: sharp pencil, clear unbroken lines, no shading, ruled label lines that touch the part.
• Food tests: always give the colour before and after, e.g. Benedict's blue to brick red.
• Name the variable you change, the one you measure and at least two you keep the same.

Free lessons: Fair tests and variables · Using a microscope

Doing papers is only half the job. The marks come from checking your answers against the mark scheme line by line and noticing which exact words got the credit.

Keep a mistakes log. Each time you lose a mark, write the question, what you wrote and what the scheme wanted. Reread it before every new paper.