Key term
CCEA A-Level Biology 1010
Biological Molecules
Topic overviewWater as a solventInorganic ions and their rolesMonosaccharides and the glycosidic bondDisaccharides and polysaccharidesLipids, triglycerides and phospholipidsAmino acids and protein structureProtein shape, conjugated proteins and prionsNucleic acids: nucleotides, DNA and RNADNA replication and the Meselson–Stahl experimentBiochemical tests and paper chromatography
Enzymes
Topic overviewEnzymes as globular proteins and the active siteSpecificity, cofactors and coenzymesActivation energy and models of enzyme actionThe effect of temperature and pHThe effect of substrate and enzyme concentrationCompetitive and non-competitive inhibitionEnzymes as biomarkers of disease and inhibitors as drugsImmobilised enzymes and biosensors
Viruses and Cell Structure
Topic overviewBacteriophage and HIV structureViral replication in host cellsProkaryotic and eukaryotic cells comparedMembrane structure: the fluid mosaic modelFunctions of membrane componentsMitochondria and chloroplastsRibosomes, endoplasmic reticulum, Golgi apparatus and lysosomesThe nucleus, the cytoskeleton and plasmodesmataPlant, fungal and animal cellsMicroscopy, cell measurement and cell fractionation
Cell Physiology and Transport
Continuity of Cells
Topic overviewThe cell cycle: interphase and the gap phasesControl points in the cell cycle and cancerChromosome structure, haploidy and diploidyMitosis: the events of the four stagesCytokinesis and the significance of mitosisAnticancer drugs and the cell cycleMeiosis I and the first divisionMeiosis II and the significance of meiosisPreparing and examining slides of cell division
Tissues and Organs
Exchange Surfaces and Gas Exchange
Topic overviewSurface area, volume and the surface area to volume ratioFeatures of efficient exchange surfacesThe need for mass transport systemsFick's law and the rate of gas exchangeGas exchange in plants and the compensation pointGas exchange at the alveolusThe respiratory tree and the mechanism of ventilationThe effects of smoking on the breathing systemUsing a respirometer to measure gas exchange
Transport in Plants
Topic overviewEpidermis, endodermis and the tissues of the rootXylem vessels and their lignification patternsPhloem: sieve-tube elements and companion cellsWater and mineral ion uptake by root hairsThe apoplast and symplast pathwaysTranspiration and the factors affecting its rateCohesion-tension theory and the transpiration streamTranslocation of organic solutes in the phloemXerophytes and hydrophytes
The Circulatory System in Mammals
Topic overviewDouble circulation and the major blood vesselsThe structure and function of arteries, veins and capillariesAtherosclerosis, atheroma and the investigation of blood vesselsThe structure of the mammalian heartThe cardiac cycle and the operation of the valvesMyogenic stimulation and the electrocardiogramBlood cells and the stained blood filmPlasma, tissue fluid and blood clottingHaemoglobin and the oxygen dissociation curveThe Bohr effect, myoglobin and altitude
Adaptation and Biodiversity
Topic overviewAdaptation and the ways organisms meet environmental challengesEcological factors and the ecological nicheSampling procedures and sampling devicesEstimating abundance, density, frequency and percentage coverThe biochemical basis of life and the levels of biodiversityMeasuring species diversity with Simpson's indexHandling data: averages, spread and the t-testTaxonomy, nomenclature and the binomial systemThe concept of a speciesThe taxonomic hierarchy from genus to kingdomPhylogenetic taxonomy and molecular evidenceThe five kingdom system: prokaryotae, protoctista and fungiPlantae, animalia and alternative classification systems
Human Impact on Biodiversity
Topic overviewMonoculture, polyculture and intensive agricultureCrop rotation and hedgerow conservationPredator strips, pesticides and integrated pest managementOrganic pollution of waterways by slurry and silage effluentEutrophication and fertiliser run-offBiological oxygen demand and reducing aquatic pollutionConservation initiatives and habitat protectionGlobal warming, climate change and biodiversity
Homeostasis and Excretion
Topic overviewPrinciples of homeostasis and negative feedbackExcretion, osmoregulation and nitrogenous wasteGross structure of the kidney and the urinary systemStructure of the nephron and its blood supplyEpithelia of the nephron and their adaptationsThe glomerular filterUltrafiltration and the forces that drive itSelective reabsorption in the proximal convoluted tubuleThe loop of Henlé and the medullary salt gradientADH, osmoreceptors and the control of water balance
Immunity
Topic overviewNatural barriers to infectionAntigens, antibodies and the antigen–antibody reactionAntibody-mediated immunity and B-lymphocytesCell-mediated immunity and T-lymphocytesActive immunity, passive immunity and vaccinationTransplant rejection and immunosuppressionBlood group polymorphism and the rhesus factorTransfusion compatibility and its consequencesAntibiotic resistance and the search for new antimicrobialsELISA and the detection of disease biomarkers
Co-Ordination and Control
Topic overviewPhytochromes and the control of floweringPlant growth substances and stem elongationThe structure of a neuroneResting potential, threshold and the action potentialImpulse propagation and the speed of conductionSynapse structure and chemical transmissionExcitatory and inhibitory post-synaptic potentialsGross structure of the eye and accommodationThe retina, rods and conesSkeletal muscle and the sliding filament theory
Populations and Communities
Topic overviewPopulation growth curves, carrying capacity and environmental resistancer-selected and K-selected speciesInteractions between populationsBiological control of pest speciesPopulation dynamics and changes in population sizeEstimating population size in the field and the laboratoryCommunities and ecosystemsSuccession and climax communities
Ecological Energetics and Nutrient Cycling
Topic overviewFood chains, food webs and detritus food chainsTrophic levels, gross and net primary productionEcological pyramids and their usefulnessEnergy transfer efficiency between trophic levelsWhy energy is lost at each trophic levelImplications for agriculture and intensive farmingThe carbon cycleThe nitrogen cycle and the role of bacteria
Respiration
Topic overviewATP and the ATP/ADP cycleGlycolysisThe mitochondrion and the sites of aerobic respirationThe link reaction and the Krebs cycleThe electron transport chain and oxidative phosphorylationATP yield from one molecule of glucoseAnaerobic respiration in animals, plants and fungiAerobic and anaerobic respiration compared, and oxygen debtRespiratory quotient and measuring respiration
Photosynthesis
Topic overviewChloroplast structure and the sites of photosynthesisPhotosynthetic pigments and paper chromatographyAbsorption spectra and action spectraPhotosystems, photoactivation and the Z-schemePhotolysis of water, reduced NADP and redox indicatorsCarbon dioxide fixation and rubiscoReduction of glycerate phosphate and regeneration of ribulose bisphosphateLimiting factors, the compensation point and measuring photosynthesis
DNA as the Genetic Code
Topic overviewGenes and the nature of the genetic codeExons, introns and RNA splicingComparing DNA and RNATranscription and RNA polymeraseTransfer RNA, ribosomes and the sites of translationTranslation and polypeptide synthesisOne gene, one polypeptide and the control of the phenotypeEpigenetics, methylation and histone modification
Gene Technology
Topic overviewThe polymerase chain reactionDNA probes and genetic markersMicroarrays, pharmacogenetics and personalised medicineGenetic fingerprinting and gel electrophoresisThe stages of gene transferGenetically modified microorganismsTransgenic animals and plantsGene therapyGenome sequencing and the Human Genome ProjectGene inactivation and knockout organismsSocial, ethical and ecological issues of gene technology
Genes and Patterns of Inheritance
Topic overviewGenotype, phenotype and the environmentChromosomes, genes and allelesMonohybrid inheritance and Mendel's first lawCodominance, multiple alleles and lethal allelesTest crossesDihybrid inheritance and Mendel's second lawAutosomes, sex chromosomes and sex determinationGene interaction and epistasisPolygenic inheritance and continuous variationThe chi-squared test
Population Genetics and Evolution
Evolutionary Trends in Plants
Evolutionary Trends in Plants
- 7 subtopics
- 20 things to know
- Unit A2 2
What Evolutionary Trends in Plants covers
Evolutionary Trends in Plants is examined in Unit A2 2, Biochemistry, Genetics and Evolutionary Trends, and drawn on again in Unit A2 3, the practical skills examination. It covers Colonising the land: the problems to be solved, the moss body plan, the fern body plan, the flowering plant body plan, comparing the three plant groups, practical study of plant specimens and where each group can live, and why.
Where it is assessed
Unit A2 2
Biochemistry, Genetics and Evolutionary Trends, and again in Unit A2 3, Practical Skills in Biology.
Check the CCEA specification ↗The 7 subtopics
Each one has its own page.
- Colonising the land: the problems to be solvedConflict at the heart of the stoma and evolutionary trend.Open →
- The moss body planRecall questions on why mosses are restricted to moist habitats, the absence of true roots, stems and leaves, rhizoids that anchor but do not absorb, support by turgor alone, and dispersal by spores only partly resistant to drying.Open →
- The fern body planSaying a fern is well differentiated and two ways a fern is supported.Open →
- The flowering plant body planSupport feature developed further in angiosperms than in ferns, wood, in terms of plant tissue and xerophytic adaptations.Open →
- Comparing the three plant groupsRecall questions comparing mosses, ferns and flowering plants on differentiation, cuticle, absorbing structures, vascular tissue, support and dispersal, and on why the trend towards independence from water is not a line of descent.Open →
- Practical study of plant specimensRecall questions on the material used, recognising the absence of true roots in a moss, identifying vascular bundles and lignified xylem in a section, epidermal peels and stomatal density, and calculating actual size from a drawing.Open →
- Where each group can live, and whyRecall questions on mosses as pioneers on bare rock, ferns in shaded damp woodland, flowering plants across almost every habitat, how root depth and the seed extend the range, and how a transect and quadrat investigation would test it.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
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What does a fern's cuticle achieve, what problem does it create, and how is that problem solved?
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What are rhizoids?
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What is an angiosperm?
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Compare the moss, the fern and the angiosperm on differentiation of the body
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Why is practical examination of specimens part of comparing the plant groups?
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How does the depth of a flowering plant's root system change what it can survive?
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Why is desiccation the central problem of terrestrial life for a plant?
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How is a moss supported?
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How does a fern's cuticle differ in effect from a moss's lack of one?
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Which features of a fern does an angiosperm also possess?
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Compare the moss, the fern and the angiosperm on the cuticle
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What would you look for in a living moss to confirm it has no true roots?
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Why are there still three plant groups, moss, fern and angiosperm, rather than one?
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Why does a plant in water need no supporting tissue?
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Why does support by turgor limit a moss's size?
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Why does the presence of a cuticle make stomata necessary?
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Give an example of a support feature developed further in angiosperms than in ferns.
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Compare the moss, the fern and the angiosperm on absorbing structures
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What would a transverse section of a fern stem show that a moss lacks?
Take Evolutionary Trends in Plants further
The same content, four other ways.
Questions from this topic
Each one with the model answer underneath.
- 1
Name four problems a plant faces on land that a plant in water does not.
Model answer
Water loss by evaporation, obtaining water and ions from the soil, supporting itself without the buoyancy of water, and reproducing without water for the gametes to swim through.
- 2
Why is desiccation the central problem of terrestrial life for a plant?
Model answer
The whole surface is exposed to air, and losing water faster than it can be replaced kills the cells.
- 3
Why does a plant in water need no supporting tissue?
Model answer
The surrounding water supports it, so it does not have to hold itself up against gravity.
- 4
Why does life on land create a transport problem that water plants do not have?
Model answer
Water is available only at the roots while photosynthesis happens in the leaves above, so the two must be connected.
- 5
How does terrestrial life change the problem of gas exchange?
Model answer
Carbon dioxide is far more available in air than in water, but any surface open enough to absorb it also loses water vapour.
- 6
State the conflict at the heart of the stoma.
Model answer
A pore open enough for carbon dioxide to enter is also open enough for water vapour to leave, so the plant must trade one against the other.
What is inside Levo
Six ways to work the same material.
Evolutionary Trends in Plants revision questions
- What does Evolutionary Trends in Plants cover in CCEA A-Level Biology?
- 7 subtopics: colonising the land: the problems to be solved, the moss body plan, the fern body plan, the flowering plant body plan, comparing the three plant groups, practical study of plant specimens and where each group can live, and why. Each one has its own page with questions and model answers.
- How is Evolutionary Trends in Plants organised?
- By the CCEA 1010 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Evolutionary Trends in Plants, 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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