Key term
Edexcel GCSE Biology 1BI0
Key Concepts in Biology
Topic overviewEukaryotic and prokaryotic cellsSpecialised cells and their adaptationsMicroscopes and magnification calculationsSize, scale and units in cell biologyEnzyme action and denaturationFactors affecting enzyme activityEnzymes in synthesis and digestion, and rate calculationsFood tests and the energy in foodDiffusion, osmosis and active transportOsmosis in potatoes and percentage change in mass
Cells and Control
Topic overviewMitosis and the cell cycleWhy mitosis matters: growth, repair and cancerGrowth, differentiation and percentile chartsStem cells and their use in medicineThe structure and function of the brainNeurones, receptors and the reflex arcThe structure and function of the eyeEye defects and how they are corrected
Genetics
Topic overviewAsexual and sexual reproductionMeiosis and the formation of gametesDNA structure, genes and the genomeExtracting DNA from fruitMendel's work and the inheritance of blood groupsAlleles, genotype and phenotypeMonohybrid crosses and sex determinationProbability and ratios from genetic crossesCauses of variation: genes and environmentThe Human Genome ProjectGenetic variation and the effects of mutation
Natural Selection and Genetic Modification
Topic overviewDarwin, Wallace and the theory of evolutionNatural selection and antibiotic resistanceFossil evidence for human evolutionStone tool evidence for human evolutionThe pentadactyl limb and the three domainsSelective breedingTissue cultureGenetic engineering and modern agricultureBenefits and risks of GM organisms
Health, Disease and the Development of Medicines
Topic overviewHealth, disease and susceptibilityPathogens and common infectionsHow pathogens spread, and the virus life cycleSexually transmitted infectionsHow plants defend themselvesPhysical barriers and chemical defencesThe immune system, immunisation and herd immunityAntibiotics and developing new medicinesAseptic technique in culturing microorganismsTesting antiseptics and antibiotics on bacterial culturesLifestyle factors and non-communicable diseaseTreatments for cardiovascular disease
Plant Structures and Their Functions
Topic overviewPhotosynthesis as an endothermic reactionLimiting factors in photosynthesisLight intensity and the rate of photosynthesisRoot hair cells, xylem and phloemTranspiration and translocationLeaf structure for photosynthesis and gas exchangeFactors affecting the rate of transpirationPlant adaptations to extreme environmentsPlant hormones, phototropism and gravitropism
Animal Coordination, Control and Homeostasis
Topic overviewHormones, endocrine glands and homeostasisThe menstrual cycle and its hormonesHormonal and barrier contraceptionHomeostasis and thermoregulationControlling blood glucose, and type 1 diabetesType 2 diabetes and body massThe urinary system and the production of ureaThe nephron, filtration and selective reabsorptionTreating kidney failure: dialysis and transplants
Exchange and Transport in Animals
Topic overviewWhy multicellular organisms need exchange surfacesAlveoli and gas exchangeRate of diffusion and Fick's lawThe blood and its componentsArteries, veins and capillariesThe heart and the circulatory systemCellular respiration as an exothermic reactionAerobic and anaerobic respiration comparedInvestigating the rate of respirationCardiac output, stroke volume and heart rate
Ecosystems and Material Cycles
Topic overviewLevels of organisation and interdependenceAbiotic and biotic factors in a communityParasitism and mutualismSampling with quadrats and transectsEstimating population size from field dataEnergy transfer between trophic levelsHuman impact on ecosystems and biodiversityFood securityThe carbon cycleThe water and nitrogen cyclesFactors affecting the rate of decompositionCalculating the rate of decay
Key Concepts in Biology
Enzymes in synthesis and digestion, and rate calculations
- 3 things to know
- Papers 1 and 2
Overview
Calculating rate as 1 divided by time and as volume per unit time, comparing rates, carbohydrases, proteases and lipases and their products, enzymes building carbohydrates, proteins and lipids, and giving calculated answers to an appropriate number of significant figures.
What you need to know
Answer each one before you reveal it.
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Numbers
Starch is fully broken down in 40 seconds. Calculate the rate of reaction.
Numbers
An enzyme releases 24 cm³ of oxygen in 30 seconds. Calculate the mean rate of oxygen production.
Questions from this subtopic
Each one with the model answer underneath.
- 1
How is the rate of an enzyme-controlled reaction calculated from the time taken for a reaction to finish?
Model answer
Divide 1 by the time taken. The rate is then expressed per second, written s⁻¹.
- 2
Starch is fully broken down in 40 seconds. Calculate the rate of reaction.
Model answer
The rate is 0.025 per second, because 1 divided by 40 gives 0.025.
- 3
An enzyme releases 24 cm³ of oxygen in 30 seconds. Calculate the mean rate of oxygen production.
Model answer
The mean rate is 0.8 cm³ per second, because 24 divided by 30 gives 0.8.
- 4
A reaction produces 15 cm³ of gas in 5 minutes. Calculate the rate in cm³ per minute.
Model answer
The rate is 3 cm³ per minute, because 15 divided by 5 gives 3.
- 5
Reaction A finishes in 20 seconds and reaction B in 80 seconds. How many times faster is reaction A?
Model answer
Reaction A is 4 times faster, because 80 divided by 20 gives 4.
- 6
Explain why a rate calculated as 1 divided by time is useful when comparing enzyme experiments.
Model answer
It converts times into a measure that increases as the reaction gets faster, so results can be compared directly across different conditions.
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