This free quiz has all 15 multiple choice questions from Section A of the OCR A Level Biology A Biological Diversity paper (H420/02), June 2024. It marks itself, so you get your score as soon as you finish.
What the multiple choice section covers
Biomass transfer, trophic levels and productivity units (6.3.1)
Magnification, resolution and cell structures in electron micrographs (2.1.1)
Genetic control of variation (6.1.2)
The degenerate genetic code and control of gene expression (2.1.3, 6.1.1)
Surface area to volume ratio data and calculations (1.1.3, 2.1.5)
Cloning plants by taking cuttings (6.2.1)
Microorganisms in food production, aseptic technique and bacterial growth curves (6.2.1)
How to use it
Section A is 15 of the 100 marks on a 2 hour 15 minute paper, so about 20 minutes is a fair share. Several questions ask which option is not correct or cannot be true, so read each stem carefully before choosing. Paper 2 tests modules 1, 2, 4 and 6, so expect Year 12 and Year 13 content side by side.
Where students lost marks on this paper (from the OCR examiners' report and mark scheme)
These points cover the whole paper, not just the multiple choice section. Each is followed by wording that gained marks.
Gene, allele and zygosity confusion: Only around 1 in 10 scored when explaining one or two peaks per locus, as many confused gene with allele, homologous with homozygous and polygenic with polymorphic.
✔ Gains credit: two peaks at a locus show the person is heterozygous with two different alleles (VNTR lengths), and one peak shows they are homozygous.
One-sided evaluation of evidence: Most candidates noted the profiles matched but then gave examples instead of weighing up weaknesses, and some mentioned twins without saying identical.
✔ Gains credit: matching profiles are very unlikely by chance, but only six loci were tested and a close relative or an identical (monozygotic) twin could share the profile.
Role of T lymphocytes: Many candidates did not mention receptors on T cells, and many said T killer cells act directly on the pathogen rather than on infected host cells.
✔ Gains credit: T cell surface receptors bind antigens on antigen-presenting cells, interleukins stimulate clonal expansion and phagocytosis, T killer cells destroy infected cells, and T cells differentiate into memory cells for a faster secondary response.
Features unique to animal cells: Fewer than 1 in 5 scored, as many gave a nucleus, membrane-bound organelles or 80S ribosomes, which plant cells also have, or a lack of chlorophyll.
✔ Gains credit: the absence of a cell wall together with the absence of chloroplasts.
What mitosis actually divides: Many candidates did not recognise that mitosis is nuclear division rather than cell division, and some placed checking DNA for mutations in G1.
✔ Gains credit: the nucleus divides during mitosis, followed by cytokinesis, with DNA checked for damage or breaks in G1 and G2.
Headline answers on synthetic biology: Answers such as 'playing God', 'designer babies' or 'tampering with nature' gained no credit.
✔ Gains credit: the idea that novel proteins could have unknown consequences, or a specific named ethical issue such as creating bioweapons.
Lab-style control variables in fieldwork: Only a minority scored, as many gave time of day or soil mineral and water content, which are unrealistic or irrelevant in a woodland study.
✔ Gains credit: practical field variables such as the age or size of the tree, the gradient of the ground, the density of surrounding trees and shading or direction of sunlight.
Keep practising
Try the multiple choice sections of the June 2024 AS paper and June 2024 Biological Processes paper, or practise by topic with the Genetics and Evolution, Biodiversity, Communicable Diseases, Cell Structure quizzes. You can also browse all our OCR A Level Biology quizzes. Our OCR A masterclasses (Year 12 on Wednesdays at 5.15pm, Year 13 on Tuesdays at 6.30pm) work through real exam questions on one topic each week.
Practising recall is so important for retention and learning. Try this quiz without books first !