Key term
Edexcel A-Level Biology B 9BI0
Biological Molecules
Topic overviewMonosaccharides, disaccharides and polysaccharidesGlycosidic bonds and condensation reactionsStarch, glycogen and cellulose structureTriglycerides and phospholipidsSaturated and unsaturated fats and lipid propertiesAmino acid structure and the peptide bondPrimary, secondary, tertiary and quaternary structureFibrous and globular proteinsThe structure of DNADNA replication and gene mutationsThe structure of RNATranscription and translationEnzymes as globular proteinsFactors affecting enzyme activityMeasuring the rate of enzyme activityUnits, uncertainty and experimental errorEnzyme inhibitionInorganic ionsThe properties of water
Cells, Viruses and Reproduction of Living Things
Topic overviewCell theory and eukaryotic cell structureProkaryotic cells and Gram stainingMicroscopy, magnification and resolutionSignificant figures, estimates and mathematical symbolsVirus structure and classificationThe lytic cycle and latencyTreating viral disease and the ethics of untested drugsThe cell cycle and its regulationMitosis and the behaviour of chromosomesMitosis in growth, repair and root tip squashesMeiosis, genetic variation and chromosome mutationsGametogenesis in mammalsFertilisation and early embryo developmentPollen and embryo sac formationDouble fertilisation in flowering plantsInvestigating pollen tube growth
Classification and Biodiversity
Exchange and Transport
Topic overviewSurface area to volume ratioThe fluid mosaic modelDiffusion, osmosis and facilitated diffusionActive transport, endocytosis and exocytosisGas exchange in insects, fish and mammalsDissecting the insect gas exchange systemGas exchange in flowering plantsThe structure of the heart and blood vesselsThe double circulatory systemThe cardiac cycleMyogenic stimulation and ECG tracesThe composition of bloodThe functions of blood and clottingAtherosclerosis and its risk factorsHaemoglobin and the Bohr effectOxygen dissociation curvesFormation of tissue fluidThe lymphatic systemXylem and phloem structureApoplastic and symplastic pathwaysThe cohesion-tension theoryMeasuring transpiration with a potometerTranslocation and the mass flow hypothesis
Energy for Biological Processes
Topic overviewAn overview of aerobic respirationGlycolysisThe link reaction and the Krebs cycleThe electron transport chainChemiosmosis and ATP yieldAnaerobic respiration and ATP yieldMeasuring respiration with a respirometerAbsorption and action spectraPhotosynthetic pigments and chromatographyChloroplast structure and the light-dependent stageThe Calvin cycleLimiting factors in photosynthesis
Microbiology and Pathogens
Topic overviewCulturing microorganisms and aseptic techniqueMeasuring bacterial growthThe bacterial growth curveBacteria as pathogensThe action of antibioticsAntibiotic resistanceOther pathogenic agentsControlling endemic diseasePhagocytosis and the humoral responseThe cell-mediated immune responseMemory cells and the secondary responseNatural and artificial immunityVaccination and herd immunity
Modern Genetics
Origins of Genetic Variation
Topic overviewMutation, meiosis and random fertilisationGenotype, phenotype and monohybrid inheritanceDihybrid crosses and pedigree diagramsAutosomal linkage and sex linkageThe chi-squared test in geneticsSelection pressures and allele frequencyGenetic drift and the founder effectThe Hardy-Weinberg equation
Control Systems
Topic overviewHomeostasis and negative feedbackChemical control in mammalsPlant growth substancesAuxins, cytokinins and apical dominancePhytochrome and photomorphogenesisThe organisation of the nervous systemBrain regions and divisions of the peripheral nervous systemThe autonomic nervous systemResting potential and the action potentialPropagation and saltatory conductionSynaptic transmissionEffects of drugs on the nervous systemThe structure of the retina and rhodopsinRods, cones and visual acuityControl of heart rateKidney structure and ultrafiltrationSelective reabsorption and the loop of HenleADH and osmoregulationThermoregulation in endotherms
Ecosystems
Topic overviewEcosystems, habitats and nichesPyramids of numbers, biomass and energyEcological techniques for measuring distributionChoosing the right ecological techniquePresenting data in tables and graphsStatistical tests in ecologyProductivity and energy transfer efficiencyDecomposers and nutrient cyclingSuccessionBiotic and abiotic factors in population changeHuman influences on ecosystemsSustainability, resource management and peer review
Energy for Biological Processes
- 12 subtopics
- 36 things to know
- Papers 1 and 3
What Energy for Biological Processes covers
How cells release energy and how plants capture it: the four stages of aerobic respiration, what happens when oxygen runs out, the pigments that absorb light, and the light-dependent and light-independent stages of photosynthesis.
Where it is assessed
Papers 1 and 3
Advanced Biochemistry, Microbiology and Genetics, then the general and practical principles paper.
Check the Pearson Edexcel specification ↗The 12 subtopics
Each one has its own page.
- An overview of aerobic respirationRecall questions on ATP as the energy currency, why respiration also releases heat, and the order and location of glycolysis, the link reaction, the Krebs cycle and oxidative phosphorylation.Open →
- GlycolysisRecall questions on glycolysis in the cytoplasm, phosphorylation of hexose as an energy investment, glycerate 3-phosphate, reduced NAD and substrate-level phosphorylation, and the net yield of pyruvate, ATP and NADH.Open →
- The link reaction and the Krebs cycleRecall questions on decarboxylation and dehydrogenation, acetyl coenzyme A, and the products of one turn of the cycle.Open →
- The electron transport chainRecall questions on the electron transport chain in the inner mitochondrial membrane, electrons from NADH and FADH2 passed on by redox reactions, proton pumping into the intermembrane space, the formation of water, and the proton motive force.Open →
- Chemiosmosis and ATP yieldRecall questions on oxidative phosphorylation, oxygen as the terminal electron acceptor, chemiosmosis through rotating ATP synthase, the cristae, and why compartmentalisation by the mitochondrial membranes is needed.Open →
- Anaerobic respiration and ATP yieldRecall questions on anaerobic respiration and why it yields far less ATP, lactate in mammalian muscle and its effect on enzymes and fatigue, and ethanol and carbon dioxide production in plants with the regeneration of NAD.Open →
- Measuring respiration with a respirometerRecall questions on how a respirometer measures respiration, carbon dioxide absorbents, the control tube and equilibration, the variables to investigate and control, calculating rate from fluid movement, adapting it for anaerobic respiration, and the safe and ethical use of organisms.Open →
- Absorption and action spectraRecall questions on absorption and action spectra and why their match shows that pigments drive photosynthesis, how pigments complement each other, and investigating the effect of light wavelength on photosynthesis with filters or LEDs.Open →
- Photosynthetic pigments and chromatographyRecall questions on why plants have several photosynthetic pigments, extracting and separating them by chromatography, and calculating and using Rf values to identify them.Open →
- Chloroplast structure and the light-dependent stageRecall questions on the chloroplast envelope, grana, thylakoids and intergranal lamellae, cyclic and non-cyclic photophosphorylation, the path of electrons through photosystems II and I, the photolysis of water, and the products of each route.Open →
- The Calvin cycleRecall questions on RuBisCO and carbon fixation, GP and GALP, and the regeneration of RuBP.Open →
- Limiting factors in photosynthesisRecall questions on limiting factors, how light intensity, carbon dioxide and temperature restrict photosynthesis, the compensation point and how to read and calculate it from a graph, gross against net photosynthesis, and shade-tolerant plants.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
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What is the function of the intermembrane space in establishing the proton gradient, and where is the proton concentration higher?
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What absorbent should a respirometer for aerobic respiration contain and why, and what does a control tube of glass beads account for?
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When investigating anaerobic respiration using a respirometer, why might the absorbent be omitted or the setup modified?
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What effect does lactate accumulation have on muscle function?
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How can Rꜰ values be used to identify unknown pigments?
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Why does cellular respiration generate heat as well as ATP?
Process
Which stage immediately follows the link reaction in aerobic respiration?
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Define glycolysis in terms of the substrate and product involved.
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Explain why CO₂ is released during the link reaction and Krebs cycle.
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Is ATP produced directly during the Krebs cycle?
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Define chemiosmosis.
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What would happen to ATP synthesis if the mitochondrial membranes lost their ability to compartmentalise?
Process
State one safety precaution when using potassium hydroxide in a respirometer experiment.
Numbers
State the formula for calculating Rꜰ value.
Process
What does the stroma contain that enables the light-independent stage to occur?
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What is the role of ATP in the regeneration of RuBP?
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Describe the relationship between light intensity and rate of photosynthesis at low light intensities.
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How would you expect results from an investigation into light wavelength and photosynthesis rate to relate to the absorption spectrum of photosynthetic pigments?
Process
What is the substrate that enters the first stage of glycolysis?
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What does an absorption spectrum show?
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What is plotted on the axes of an absorption spectrum?
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Define grana in the context of chloroplast structure.
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What is the lamellar structure of a chloroplast?
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Explain why ATP is described as a source of energy for metabolic reactions.
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What is the immediate product when hexose is phosphorylated at the start of glycolysis?
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In which part of the cell does the link reaction occur?
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Where in the mitochondrion is the electron transport chain located?
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Define oxidative phosphorylation.
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What is anaerobic respiration?
Numbers
How many ATP molecules are produced from one hexose molecule during aerobic respiration?
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Define an action spectrum.
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Why do plants possess multiple photosynthetic pigments rather than just one?
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What three products are generated by non-cyclic photophosphorylation?
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What is the stroma of a chloroplast?
Numbers
How many carbon atoms are present in GP?
Take Energy for Biological Processes further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Phosphorylation vs Dephosphorylation
Phosphorylation: addition of a phosphate group. Dephosphorylation: removal of a phosphate group.
Oxidation vs Reduction
Oxidation: loss of electrons or hydrogen. Reduction: gain of electrons or hydrogen.
Photophosphorylation vs Oxidative phosphorylation
Photophosphorylation: ATP production driven by light-dependent electron flow. Oxidative phosphorylation: ATP production driven by respiratory electron flow.
Questions from this topic
Each one with the model answer underneath.
- 1
What molecule is produced by cellular respiration and serves as the energy currency for metabolic reactions?
Model answer
ATP.
- 2
Explain why ATP is described as a source of energy for metabolic reactions.
Model answer
ATP stores chemical energy in its phosphate bonds; when hydrolysed, it releases energy that can be coupled to drive endergonic metabolic reactions in cells.
- 3
Besides ATP, what other form of energy is released during cellular respiration?
Model answer
Heat.
- 4
Why does cellular respiration generate heat as well as ATP?
Model answer
Not all the energy released from the oxidation of respiratory substrates is captured in ATP; some is lost as heat due to the inefficiency of energy transfer in metabolic reactions.
- 5
Name the first stage of aerobic respiration.
Model answer
Glycolysis.
- 6
What is the name of the stage that connects glycolysis to the Krebs cycle?
Model answer
The link reaction.
What is inside Levo
Six ways to work the same material.
Energy for Biological Processes revision questions
- What does Energy for Biological Processes cover in Edexcel A-Level Biology B?
- 12 subtopics: an overview of aerobic respiration, glycolysis, the link reaction and the krebs cycle, the electron transport chain, chemiosmosis and atp yield, anaerobic respiration and atp yield, measuring respiration with a respirometer, absorption and action spectra, photosynthetic pigments and chromatography, chloroplast structure and the light-dependent stage, the calvin cycle and limiting factors in photosynthesis. Each one has its own page with questions and model answers.
- How is Energy for Biological Processes organised?
- By the Edexcel 9BI0 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Energy for Biological Processes, on a schedule.
Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.
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