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
Cell Physiology and Transport
- 7 subtopics
- 21 things to know
- Unit AS 1
What Cell Physiology and Transport covers
Cell Physiology and Transport is examined in Unit AS 1, Molecules and Cells, and drawn on again in Unit AS 3, the practical skills examination. It covers diffusion and facilitated diffusion, membrane permeability, osmosis and water potential, plant and animal cells in different solutions, calculating the water potential of a cell, active transport, endocytosis and exocytosis and measuring water potential and solute potential in plant tissue.
Where it is assessed
Unit AS 1
Molecules and Cells, and again in Unit AS 3, Practical Skills in AS Biology.
Check the CCEA specification ↗The 7 subtopics
Each one has its own page.
- Diffusion and facilitated diffusionTerm diffusion, state of a system once diffusion has reached equilibrium and term facilitated diffusion.Open →
- Membrane permeabilityWhy a fat-soluble substance crosses the bilayer easily, three substances that cross a membrane through the bilayer itself and why an ion cannot cross the bilayer directly.Open →
- Osmosis and water potentialTerm osmosis, term water potential and water potential of pure water at atmospheric pressure.Open →
- Plant and animal cells in different solutionsWhy an animal cell cannot resist bursting in pure water, what happens to a plant cell placed in pure water and term turgor.Open →
- Calculating the water potential of a cellRecall questions on water potential as solute potential plus pressure potential, working the sum in both directions, reading the direction of water movement between two values, and what the figures mean at full turgor and at incipient plasmolysis.Open →
- Active transport, endocytosis and exocytosisTerm active transport, part played by a carrier protein in active transport and why a respiratory inhibitor such as cyanide stops active transport.Open →
- Measuring water potential and solute potential in plant tissueRecall questions on the change in mass and change in length methods, why percentage change is plotted, blotting and the variables that must be controlled, incipient plasmolysis, and why the value is read from the line rather than from the nearest solution.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
What happens to an animal cell and to a plant cell placed in pure water and in a concentrated solution?
Key term
Describe how cylinders of potato tissue are prepared for a weighing investigation of water potential.
Key term
What is the state of a system once diffusion has reached equilibrium?
Key term
Which substances can pass directly through the phospholipid bilayer?
Key term
State the relationship between the water potential of a cell and its solute and pressure potentials.
Key term
Which molecule supplies the energy for active transport?
Key term
State two substances that enter or leave a respiring cell by simple diffusion.
Key term
Name three substances that cross a membrane through the bilayer itself.
Key term
Define the term water potential.
Key term
Describe what happens to a red blood cell placed in pure water.
Numbers
A cell has a solute potential of −800 kPa and a pressure potential of +300 kPa. Calculate its water potential.
Key term
Describe the part played by a carrier protein in active transport.
Key term
Why are the potato cylinders blotted before each weighing?
Key term
How does a steeper concentration gradient affect the rate of diffusion?
Key term
Explain why water can cross the bilayer even though it is a polar molecule.
Key term
What symbol is used for water potential and in what units is it measured?
Process
Name the process by which an animal cell bursts in a solution of higher water potential.
Numbers
A cell has a solute potential of −1400 kPa and a pressure potential of +600 kPa. Calculate its water potential.
Key term
Explain why cells that carry out a great deal of active transport contain many mitochondria.
Numbers
State the equation used to calculate the percentage change in mass of a tissue sample.
Take Cell Physiology and Transport further
The same content, four other ways.
Questions from this topic
Each one with the model answer underneath.
- 1
Define the term diffusion.
Model answer
Diffusion is the net movement of particles from a region of higher concentration to a region of lower concentration, down a concentration gradient.
- 2
Why is diffusion described as a passive process?
Model answer
It results from the random kinetic movement of the particles themselves, so the cell expends no energy on it.
- 3
What is the state of a system once diffusion has reached equilibrium?
Model answer
The particles are evenly distributed, and although they continue to move at random there is no further net movement in either direction.
- 4
State two substances that enter or leave a respiring cell by simple diffusion.
Model answer
Oxygen diffuses into the cell and carbon dioxide diffuses out of it.
- 5
How does a steeper concentration gradient affect the rate of diffusion?
Model answer
A steeper gradient increases the rate, because the difference in the number of particles moving each way is greater.
- 6
How does a rise in temperature affect the rate of diffusion?
Model answer
The particles gain kinetic energy and move faster, so the rate of diffusion increases.
What is inside Levo
Six ways to work the same material.
Cell Physiology and Transport revision questions
- What does Cell Physiology and Transport cover in CCEA A-Level Biology?
- 7 subtopics: diffusion and facilitated diffusion, membrane permeability, osmosis and water potential, plant and animal cells in different solutions, calculating the water potential of a cell, active transport, endocytosis and exocytosis and measuring water potential and solute potential in plant tissue. Each one has its own page with questions and model answers.
- How is Cell Physiology and Transport organised?
- By the CCEA 1010 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Cell Physiology and Transport, 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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