Key term
CCEA AS-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
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. CCEA AS Biology students sit this topic in the first year.
- 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.
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What is the state of a system once diffusion has reached equilibrium?
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Which substances can pass directly through the phospholipid bilayer?
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State the relationship between the water potential of a cell and its solute and pressure potentials.
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Which molecule supplies the energy for active transport?
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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.
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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.
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Why are the potato cylinders blotted before each weighing?
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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
- Is Cell Physiology and Transport examined at AS in CCEA Biology?
- Yes. It sits in Unit AS 1, which you take in the first year, so it is on the AS paper as well as counting towards the full A level.
- What does Cell Physiology and Transport cover in CCEA AS-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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