OCR B A-level Biology Year 13 revision

Topic 4.1: Energy for biological processes

It builds on what you learned at AS in Chemicals for life, and takes it further.

There are 5 parts: we start with respiration, and finish with the practical on rate of photosynthesis and dehydrogenase activity in chloroplasts.

1. 4.1.1Respiration31 questions
2. 4.1.2Respiratory substrates and the respiratory quotient25 questions
3. 4.1.3PhotosynthesisFree 44 questions
4. 4.1.4Practical: chromatography of photosynthetic pigments (Rf values)15 questions
5. 4.1.5Practical: rate of photosynthesis and dehydrogenase activity in chloroplasts43 questions

Topic 4.2: Populations and ecosystems

It builds on what you learned at AS in Biodiversity, classification and evolution, and takes it further.

There are 9 parts: we start with energy and ecosystems, and finish with sustainable management of ecosystems.

1. 4.2.1Energy and ecosystems65 questions
2. 4.2.2Nutrient cycles30 questions
3. 4.2.3The carbon cycleFree 39 questions
4. 4.2.4Populations in ecosystems70 questions
5. 4.2.5Ecological sampling: random sampling, quadrats, transects and mark-release-recapture75 questions
6. 4.2.6Practical: effect of an environmental factor on the distribution of a species28 questions
7. 4.2.7Statistical tests in ecology: Spearman's rank, t-test and Simpson's index of diversity23 questions
8. 4.2.8Climate change and its effects on ecosystems73 questions
9. 4.2.9Sustainable management of ecosystems: forestry, fisheries and conservation72 questions

Topic 5.1: Genetics and inheritance

It builds on what you learned at AS in Cell division and Biodiversity, classification and evolution, and takes it further.

There are 9 parts: we start with mutations, and finish with artificial selection and selective breeding.

1. 5.1.1MutationsFree 23 questions
2. 5.1.2InheritanceFree 33 questions
3. 5.1.3Autosomal linkage and epistasis26 questions
4. 5.1.4Chi-squared test for genetic crosses22 questions
5. 5.1.5Populations and Hardy–Weinberg35 questions
6. 5.1.6Types of natural selection: stabilising, directional and disruptive31 questions
7. 5.1.7Genetic drift, founder effect and population bottlenecks28 questions
8. 5.1.8Evolution and speciation32 questions
9. 5.1.9Artificial selection and selective breeding23 questions

Topic 5.2: Gene expression and genetic engineering

It builds on what you learned at AS in Development of organisms, and takes it further.

There are 21 parts: we start with transcription factors and control of transcription, and finish with measuring microbial growth and growth curves.

1. 5.2.1Transcription factors and control of transcriptionFree 31 questions
2. 5.2.2The lac operon35 questions
3. 5.2.3Epigenetics: DNA methylation and histone modification42 questions
4. 5.2.4RNA interference and post-transcriptional control of gene expression24 questions
5. 5.2.5Homeobox genes, apoptosis and the control of body plan development30 questions
6. 5.2.6Gene expression, stem cells and cancer78 questions
7. 5.2.7Genome projects22 questions
8. 5.2.8Gene technologies42 questions
9. 5.2.9DNA sequencing methods and bioinformaticsFree 38 questions
10. 5.2.10Recombinant DNA technology: restriction enzymes, vectors and transformation of organisms65 questions
11. 5.2.11The polymerase chain reaction (PCR)27 questions
12. 5.2.12Gel electrophoresis and DNA profiling (genetic fingerprinting)24 questions
13. 5.2.13DNA probes, genetic screening and personalised medicine35 questions
14. 5.2.14Gene therapy25 questions
15. 5.2.15Ethical, social and economic issues of genetic technologies and GM organisms30 questions
16. 5.2.16Natural and artificial cloning in plants: vegetative propagation, cuttings and tissue cultureFree 32 questions
17. 5.2.17Cloning in animals: embryo splitting and somatic cell nuclear transfer32 questions
18. 5.2.18Microorganisms in biotechnology: food, drink and medicine production37 questions
19. 5.2.19Immobilised enzymes, and batch and continuous culture49 questions
20. 5.2.20Aseptic technique and culturing microorganismsFree 33 questions
21. 5.2.21Measuring microbial growth and growth curves23 questions

Topic 5.3: Control: nervous and hormonal communication

It builds on what you learned at AS in Transport and gas exchange, and takes it further.

There are 18 parts: we start with neurones, and finish with the practical on effect of plant growth substances on plant growth and germination.

1. 5.3.1Neurones: sensory, relay and motor neurones, and the myelin sheath21 questions
2. 5.3.2Stimuli, receptors and plant responsesFree 34 questions
3. 5.3.3Photoreceptors: rod and cone cells and the retina79 questions
4. 5.3.4Reflex arcs and simple reflexes37 questions
5. 5.3.5Nervous coordination31 questions
6. 5.3.6Synapses: cholinergic synapses, neuromuscular junctions, summation and drugs22 questions
7. 5.3.7Organisation of the nervous system: CNS, PNS, somatic and autonomic divisionsFree 45 questions
8. 5.3.8Structure and functions of the human brain35 questions
9. 5.3.9Brain imaging techniques: CT, MRI, fMRI and PET33 questions
10. 5.3.10Skeletal muscle35 questions
11. 5.3.11Control of heart rate63 questions
12. 5.3.12The endocrine system and mechanisms of hormone action35 questions
13. 5.3.13Control of blood glucose69 questions
14. 5.3.14Treatments for diabetes: insulin, genetically engineered insulin and stem cell research47 questions
15. 5.3.15Plant hormones: auxins, gibberellins, cytokinins, ethene and abscisic acidFree 41 questions
16. 5.3.16Plant responses: leaf abscission, stomatal closure, seed germination, apical dominance and fruit ripening40 questions
17. 5.3.17Commercial uses of plant growth regulators33 questions
18. 5.3.18Practical: effect of plant growth substances on plant growth and germination35 questions

Topic 5.4: Homeostasis

It builds on what you learned at AS in Transport and gas exchange, and takes it further.

There are 8 parts: we start with principles of homeostasis and negative feedback, and finish with the practical on dilution series and colorimetric calibration curve for glucose concentration.

1. 5.4.1Principles of homeostasis and negative feedbackFree 30 questions
2. 5.4.2Thermoregulation in endotherms and ectotherms24 questions
3. 5.4.3The liver: structure, deamination, urea and the ornithine cycle28 questions
4. 5.4.4The kidney: nephron structure, ultrafiltration and selective reabsorption26 questions
5. 5.4.5Control of blood water potential50 questions
6. 5.4.6Kidney failure: dialysis and transplantation30 questions
7. 5.4.7Urine analysis and diagnostic testing (pregnancy and drug tests)27 questions
8. 5.4.8Practical: dilution series and colorimetric calibration curve for glucose concentration41 questions

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