Numbers
WJEC AS-Level Biology 601-5290-0
Chemical Elements Are Joined Together to Form Biological Compounds
Topic overviewInorganic IonsBiological Importance of WaterCarbohydrates: Monosaccharides and DisaccharidesCarbohydrates: Polysaccharides and Alpha/Beta Glucose IsomerismLipids: Triglycerides and PhospholipidsLipids: Saturated and Unsaturated Fat in Human HealthAmino Acids and Proteins: Primary to Quaternary StructureAmino Acids and Proteins: Fibrous and Globular FormsCondensation and Hydrolysis: Peptide and GlycosidicFood Tests for Biological Molecules
Cell Structure and Organisation
Topic overviewEukaryotic Cell Ultrastructure: OrganellesEukaryotic Cell Ultrastructure: FunctionsProkaryotic Cells, Viruses and Cell Theory: Comparing Cell StructuresProkaryotic Cells, Viruses and Cell Theory: Electron MicrographsLevels of Organisation and Light Microscopy: Tissues and OrgansLevels of Organisation and Light Microscopy: Organ Systems and Microscope CalibrationLevels of Organisation and Light Microscopy: Magnification and Scientific Drawing
Cell Membranes and Transport
Topic overviewPlasma Membrane Structure and Permeability: Fluid-Mosaic ModelPlasma Membrane Structure and Permeability: Factors Affecting PermeabilityTransport Across Membranes: Diffusion, Osmosis and Water PotentialTransport Across Membranes: Facilitated Diffusion, Active Transport and PinocytosisTransport Across Membranes: Phagocytosis and Exocytosis
Biological Reactions Are Regulated by Enzymes
Topic overviewEnzymes as Biological Catalysts: Metabolism, Extracellular Action and Induced FitEnzymes as Biological Catalysts: Activation EnergyFactors Affecting Enzyme Activity: Temperature and SubstrateFactors Affecting Enzyme Activity: Enzyme Concentration, Denaturation and BuffersEnzyme InhibitionImmobilised Enzymes in Industry
Nucleic Acids and Their Functions
Topic overviewNucleotides, Chemical Energy and ATP: StructureNucleotides, Chemical Energy and ATP: Role as Energy CarrierDNA and RNA StructureSemi-conservative Replication, Meselson and Stahl experimentThe Genetic Code: Triplet CodeThe Genetic Code: Exons and IntronsProtein Synthesis: Transcription, Translation and tRNAProtein Synthesis: One Gene-One Polypeptide and Polypeptide Modification
Genetic Information Is Copied and Passed on to Daughter Cells
Topic overviewThe Cell Cycle and Mitosis: Interphase and StagesThe Cell Cycle and Mitosis: Cytokinesis, Significance in Renewal and RepairThe Cell Cycle and Mitosis: Root Tip Squash and Mitotic IndexMeiosis: Meiosis I and Meiosis II, crossing over and independent assortmentMeiosis: differences from mitosis
All Organisms Are Related Through Their Evolutionary History
Topic overviewClassification: Hierarchical Groups, Need and Tentative NatureClassification: Three Domains and Five KingdomsAssessing RelatednessSpecies Concept and Binomial SystemBiodiversity and Its Assessment: Habitat LevelBiodiversity and Its Assessment: Genetic Level and Molecular LevelNatural Selection as the Source of Biodiversity and Anatomical, Physiological and Behavioural Adaptations
Adaptations for Gas Exchange
Topic overviewSurface Area to Volume Ratio and Gas Exchange in Small Organisms: AmoebaSurface Area to Volume Ratio and Gas Exchange in Small Organisms: Flatworm and EarthwormSpecialised Respiratory Surfaces and Ventilation in Bony Fish: Counter-currentSpecialised Respiratory Surfaces and Ventilation in Bony Fish: Parallel FlowGas Exchange in Terrestrial Animals: Human Breathing SystemGas Exchange in Terrestrial Animals: VentilationGas Exchange in Terrestrial Animals: the Insect Tracheal SystemThe Angiosperm Leaf: StructureThe Angiosperm Leaf: Photosynthetic RoleThe Angiosperm Leaf: Stomatal Control of Gas Exchange
Adaptations for Transport
Topic overviewVascular Systems Across Animal Groups: Earthworm and InsectVascular Systems Across Animal Groups: Fish and MammalThe Mammalian Heart and Circulation: Blood Vessels and Cardiac CycleThe Mammalian Heart and Circulation: Sino-atrial Node, Purkyne Fibres and ElectrocardiogramsBlood and the Transport of Respiratory Gases: Erythrocytes, Plasma and Dissociation CurvesBlood and the Transport of Respiratory Gases: Bohr Effect and Chloride ShiftTransport of Nutrients, Hormones, Excretory Products and HeatTissue Fluid, Lymph and OedemaWater Uptake and Movement Through the Root: Dicotyledon Root Structure and ApoplastWater Uptake and Movement Through the Root: Symplast, Vacuolar Pathways and EndodermisXylem, the Transpiration Stream and Plant Water Adaptations: Cohesion-Tension TheoryXylem, the Transpiration Stream and Plant Water Adaptations: Hydrophytes and XerophytesPhloem Structure and Translocation from Source to Sink: Mass Flow ModelsPhloem Structure and Translocation from Source to Sink: Experimental Evidence
Adaptations for Nutrition
Topic overviewModes of Nutrition: Autotrophic, Heterotrophic and HolozoicModes of Nutrition: Parasitic, and Digestion in Amoeba and Hydra to Tube GutsThe Human Gut: Adaptations to an Omnivorous DietThe Human Gut: EnzymesThe Human Gut: ConditionsHerbivore, Carnivore and Parasite Adaptations: Guts and DentitionHerbivore, Carnivore and Parasite Adaptations: Ruminants, Taenia and Pediculus
Working Scientifically: Practical Skills
Topic overviewThe A2 Unit 5 Practical Examination Tasks: Experimental TaskThe A2 Unit 5 Practical Examination Tasks: Practical Analysis TaskIndependent Thinking and Use of Scientific Methods and Practices: Solving Problems in Practical ContextsIndependent Thinking and Use of Scientific Methods and Practices: Identifying and Following InstructionsIndependent Thinking and Use of Scientific Methods and Practices: Making and Keeping RecordsIndependent Thinking and Use of Scientific Methods and Practices: Presenting DataNumeracy in Practical Contexts, Research and Referencing: Plotting, Interpreting Graphs and ProcessingNumeracy in Practical Contexts, Research and Referencing: Analysing Data, Margins of Error and AccuracyNumeracy in Practical Contexts, Research and Referencing: Precision and OnlineNumeracy in Practical Contexts, Research and Referencing: Offline Research Skills
Use of Apparatus and Techniques
Topic overviewMeasurement and Laboratory Technique: Quantitative ApparatusMeasurement and Laboratory Technique: InstrumentationMeasurement and Laboratory Technique: Glassware Including Serial DilutionsMicroscopy, Scientific Drawing and Separation and Identification Techniques: Light MicroscopeMicroscopy, Scientific Drawing and Separation and Identification Techniques: Annotated Drawings and Food TestsMicroscopy, Scientific Drawing and Separation and Identification Techniques: ChromatographyWorking with Organisms and Aseptic TechniqueViable Counts, Dissection and Fieldwork SamplingMark-Release-Recapture, Quadrats and ICT for Data Collection
Mathematical Requirements (Appendix C)
Topic overviewArithmetic and Numerical Computation: Appropriate Units, Decimal and Standard FormArithmetic and Numerical Computation: Ratios, Percentages and Estimating ResultsArithmetic and Numerical Computation: Power, Exponential and Logarithmic FunctionsHandling Data: Significant Figures, Arithmetic Means and MeanHandling Data: Median, Frequency Tables and HistogramsHandling Data: Scatter DiagramsProbability, Sampling, Statistical Tests and Uncertainty: Simple Probability and SelectingProbability, Sampling, Statistical Tests and Uncertainty: Using the Chi-squared TestProbability, Sampling, Statistical Tests and Uncertainty: Correlation CoefficientProbability, Sampling, Statistical Tests and Uncertainty: Standard DeviationAlgebra and Magnification: Mathematical Symbols and Changing the Subject of an EquationAlgebra and Magnification: Substituting Values, Solving Equations and Using LogarithmsGraphs: Translating Between Graphical, Plotting Two Variables and Linear RelationshipsGraphs: Intercepts, Rate of Change and Slope of a Tangent to a CurveGeometry: Circumferences, Surface Areas and Volumes of Regular Shapes
How Science Works (Appendix D)
Topic overviewDeveloping and Communicating Scientific Explanations: Using Theories, Models and IdeasDeveloping and Communicating Scientific Explanations: Posing Scientific QuestionsScientific Methodology, Evidence and Evaluation: Appropriate Methodology Including ICTScientific Methodology, Evidence and Evaluation: Analysing and Conflicting DataScience, Society and Ethics: How Scientific Knowledge Develops Over TimeScience, Society and Ethics: Risks, Ethical Treatment of Humans and Other OrganismsScience, Society and Ethics: Environment and How Society Uses Science
Cell Membranes and Transport
- 5 subtopics
- 15 things to know
- AS Unit 1
What Cell Membranes and Transport covers
Cell Membranes and Transport is examined on AS Unit 1 of WJEC Biology, Basic Biochemistry and Cell Organisation. 55 recall questions across 5 subtopics.
Where it is assessed
AS Unit 1
Basic Biochemistry and Cell Organisation.
Check the WJEC specification ↗The 5 subtopics
Each one has its own page. WJEC AS Biology students sit this topic in the first year.
- Plasma Membrane Structure and Permeability: Fluid-Mosaic ModelRecall questions on Fluid-Mosaic Model.Open →
- Plasma Membrane Structure and Permeability: Factors Affecting PermeabilityRecall questions on Factors Affecting Permeability.Open →
- Transport Across Membranes: Diffusion, Osmosis and Water PotentialRecall questions on Diffusion, Osmosis and Water Potential.Open →
- Transport Across Membranes: Facilitated Diffusion, Active Transport and PinocytosisRecall questions on Facilitated Diffusion, Active Transport and Pinocytosis.Open →
- Transport Across Membranes: Phagocytosis and ExocytosisRecall questions on Phagocytosis and Exocytosis.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
What effect does increasing temperature have on the permeability of a cell membrane, and why?
Numbers
Give the symbol and unit of water potential, the equation linking it to solute and pressure potential, and how turgor arises.
Key term
How does turgor support a young plant?
Key term
How does a channel protein differ from a carrier protein?
Key term
Do pinocytosis, phagocytosis and exocytosis require energy? Explain.
Key term
Why do organic solvents such as ethanol increase membrane permeability?
Key term
How does a very low or very high pH affect the plasma membrane?
Key term
State five factors that affect the rate of diffusion.
Key term
Why is percentage change in mass, rather than the actual change, calculated in an osmosis investigation with potato cylinders?
Key term
Name the principal components of the plasma membrane.
Key term
In the beetroot investigation, what is actually measured?
Key term
Why can a large multicellular animal not rely on diffusion alone to supply its cells with oxygen?
Key term
What happens to a plant cell placed in a concentrated sucrose solution?
Key term
Why must the potato cylinders in an osmosis investigation be blotted before each weighing?
Take Cell Membranes and Transport further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Diffusion vs Active transport
Diffusion: net particle movement down a concentration gradient. Active transport: energy-dependent movement against a concentration gradient.
Questions from this topic
Each one with the model answer underneath.
- 1
Name the principal components of the plasma membrane.
Model answer
A phospholipid bilayer, intrinsic and extrinsic proteins, cholesterol, and glycoproteins and glycolipids.
- 2
Why is the membrane model described as fluid-mosaic?
Model answer
It is fluid because the phospholipid molecules are free to move sideways within their layer, and it is a mosaic because the protein molecules are scattered irregularly through the bilayer like the tiles of a mosaic.
- 3
How are the phospholipids arranged in the membrane?
Model answer
They form a double layer with their hydrophilic phosphate heads facing outwards into the watery surroundings and their hydrophobic fatty acid tails pointing inwards towards each other.
- 4
What is an intrinsic protein and what does it do?
Model answer
An intrinsic protein spans the whole bilayer, and such proteins act as channels, carriers, pumps or enzymes in the transport of substances across the membrane.
- 5
What is an extrinsic protein?
Model answer
An extrinsic protein is one that lies on the surface of the bilayer rather than passing through it, and it may act as a receptor, an enzyme, or provide mechanical support.
- 6
What is the role of cholesterol in the plasma membrane?
Model answer
Cholesterol molecules sit between the phospholipids and restrict their movement, which reduces fluidity and leakiness at higher temperatures while keeping the membrane from becoming too rigid when cold, and it adds mechanical stability.
What is inside Levo
Six ways to work the same material.
Cell Membranes and Transport revision questions
- Is Cell Membranes and Transport examined at AS in WJEC Biology?
- Yes. It sits in AS Unit 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 Membranes and Transport cover in WJEC AS-Level Biology?
- 5 subtopics: plasma membrane structure and permeability: fluid-mosaic model, plasma membrane structure and permeability: factors affecting permeability, transport across membranes: diffusion, osmosis and water potential, transport across membranes: facilitated diffusion, active transport and pinocytosis and transport across membranes: phagocytosis and exocytosis. Each one has its own page with questions and model answers.
- How is Cell Membranes and Transport organised?
- By the WJEC 601-5290-0 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Cell Membranes 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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