Key term
WJEC A-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
Importance of ATP
Photosynthesis Uses Light Energy to Synthesise Organic Molecules
Topic overviewChloroplasts and Light Harvesting: Distribution and TransductionChloroplasts and Light Harvesting: Pigments and WavelengthsChloroplasts and Light Harvesting: Chromatography of PigmentsThe Light-dependent Stage: Cyclic and Non-cyclic PhotophosphorylationThe Light-dependent Stage: Photolysis and Reduction of NADPThe Light-independent Stage: Rubisco, Glycerate-3-phosphate and Triose PhosphateThe Light-independent Stage: RuBP Regeneration, Synthesis of Carbohydrates and Amino AcidsLimiting Factors in PhotosynthesisInvestigating the Rate of Photosynthesis and the Role of NitrogenMagnesium in Plant Metabolism
Respiration Releases Chemical Energy in Biological Processes
Topic overviewGlycolysis, Acetyl Coenzyme A and the Krebs Cycle: Triose Phosphate and PyruvateGlycolysis, Acetyl Coenzyme A and the Krebs Cycle: Reduced NAD, FAD as Electron and Proton SourcesEnergy Budgets of Aerobic and Anaerobic Glucose BreakdownUse of Lipids and Amino Acids in RespirationMeasuring the Rate of Respiration in Yeast
Microbiology
Population Size and Ecosystems
Topic overviewPopulation Growth and Its Regulation: Birth and ImmigrationPopulation Growth and Its Regulation: Emigration, Competition and Carrying CapacityPopulation Growth and Its Regulation: Density Dependent and Density Independent FactorsSampling Techniques for the AbundanceDistribution of Organisms in a HabitatHabitats, Communities and Sun as Energy SourceBiomass, Productivity and Transfer Through Trophic LevelsSuccession: Secondary Succession and PioneersSuccession: Seres and Climax CommunitiesNutrient Cycles and Human Impact: Organic Breakdown and Carbon CycleNutrient Cycles and Human Impact: Climate Change, Nitrogen Cycle and NitrificationNutrient Cycles and Human Impact: Fertilisers and Eutrophication
Human Impact on the Environment
Homeostasis and the Kidney
Topic overviewHomeostasis: Dynamic Equilibrium, Negative Feedback and Positive FeedbackKidney and Nephron Structure and Function: Nephron Structure and UltrafiltrationKidney and Nephron Structure and Function: Selective ReabsorptionKidney and Nephron Structure and Function: Nitrogenous Excretion and Kidney Practical WorkHormonal Control of Water Balance: ADH and OsmoreceptorsThe Loop of Henle, Excretory Adaptations and Kidney FailureTreating Kidney Failure: Dialysis and Transplants
The Nervous System
Topic overviewOrganisation of the Nervous Response: Receptors to Effectors and Spinal CordOrganisation of the Nervous Response: Spinal Nerves, Dorsal and Ventral RootsOrganisation of the Nervous Response: Simple Reflex Arc and the Cnidarian Nerve Net ComparedNeurones and the Nerve Impulse: Motor Neurone Structure and NatureNeurones and the Nerve Impulse: Transmission of the Impulse and Oscilloscope TracesNeurones and the Nerve Impulse: Speed of ConductionSynapses: Structure and Synaptic TransmissionSynapses: Effects of Organophosphates and Psychoactive Drugs
Sexual Reproduction in Humans
Topic overviewHuman Reproductive Systems and Gametogenesis: Ovary and Testis HistologyHuman Reproductive Systems and Gametogenesis: Spermatogenesis and OogenesisHuman Reproductive Systems and Gametogenesis: Fertilisation and ImplantationEndocrine Control of Reproduction: Menstrual CycleEndocrine Control of Reproduction: Menstruation, Pregnancy and BirthEndocrine Control of Reproduction: Birth, Lactation and Role of the Placenta
Sexual Reproduction in Plants
Inheritance
Topic overviewMendelian Inheritance: AllelesMendelian Inheritance: Monohybrid Crosses with CodominanceMendelian Inheritance: Dihybrid Crosses with LinkageTesting Genetic Outcomes and Sex Linkage: Chi-squared TestTesting Genetic Outcomes and Sex Linkage: Haemophilia and Duchenne Muscular DystrophyMutation and Control of Gene Expression: Sickle Cell AnaemiaMutation and Control of Gene Expression: Down's Syndrome and MutagensMutation and Control of Gene Expression: Carcinogens, Oncogenes and Epigenetics
Variation and Evolution
Topic overviewVariation and Selection Pressures: Genetic, Environmental Causes and ContinuousVariation and Selection Pressures: Discontinuous, Non-heritable Variation and Intra-specific CompetitionVariation and Selection Pressures: Selective AgenciesPopulation Genetics: Gene Pool, Genetic Drift and Changing Allele FrequenciesPopulation Genetics: Hardy-Weinberg PrincipleIsolationSpeciation and Darwin's Theory of Evolution
Application of Reproduction and Genetics
Topic overviewGenome Sequencing and Its Ethics: Human Genome Project and 100K Genome ProjectGenome Sequencing and Its Ethics: Genomes of Other Organisms and Screening of EmbryosGenetic Fingerprinting and Recombinant DNA TechnologyGenetic Fingerprinting and Recombinant DNA Technology: Electrophoresis and Bacterial PlasmidsGenetic Fingerprinting and Recombinant DNA Technology: Insulin and GM CropsGene TherapyGenomics in Future Healthcare and Use of Stem Cells
DiseaseOption A
AntibioticsOption A
Immune ResponseOption A
Topic overviewNon-specific Defences: Skin Flora, Connective Tissue and InflammationNon-specific Defences: Phagocytosis, Clotting and Ciliated EpitheliumSpecific Immunity: Development of Responses to Foreign Antigens and HumoralSpecific Immunity: Cell-mediated Immunity, Roles of T and B LymphocytesActive and Passive ImmunityImmunisation Programmes, Effectiveness and Ethics
Skeletal TissuesOption B
Topic overviewCartilage and Compact Bone: Hyaline and Yellow ElasticCartilage and Compact Bone: White Fibrous Cartilage, Organic and Inorganic Matrix ComponentsCartilage and Compact Bone: Haversian SystemsBone Remodelling and Bone Disorders: Osteoblasts, Osteoclasts and RicketsBone Remodelling and Bone Disorders: Osteomalacia, Osteoporosis and Brittle Bone DiseaseSkeletal Muscle: Structure and UltrastructureSkeletal Muscle: Sliding Filament Theory and FastSkeletal Muscle: Slow Twitch Fibres and Creatine PhosphateSkeletal Muscle: Lactic Acid and Energy Sources
Structure and Function of Human SkeletonOption B
JointsOption B
The BrainOption C
Topic overviewStructure and Functions of the Human Brain: Cerebrum, Hypothalamus and HippocampusStructure and Functions of the Human Brain: Cerebellum and Medulla OblongataSympathetic Nervous SystemParasympathetic Nervous System and Hypothalamus as the Nervous-Endocrine LinkThe Cerebral Cortex: Sensory and Motor AreasThe Cerebral Cortex: Motor Homunculi, Language and Speech Areas
NeuroscienceOption C
BehaviourOption C
Topic overviewInnate and Learned Behaviour: Escape Reflexes and KinesesInnate and Learned Behaviour: Taxes in WoodliceInnate and Learned Behaviour: Habituation, Imprinting and Operant ConditioningSocial Behaviour: Primate Societies, Advantages and Disadvantages of Group LivingSocial Behaviour: Insect Caste Systems and Vertebrate Dominance HierarchiesTerritorial and Courtship BehaviourRole of Sexual Selection in Their Evolution
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
Chemical Elements Are Joined Together to Form Biological Compounds
- 10 subtopics
- 30 things to know
- AS Unit 1
What Chemical Elements Are Joined Together to Form Biological Compounds covers
Chemical Elements Are Joined Together to Form Biological Compounds is examined on AS Unit 1 of WJEC Biology, Basic Biochemistry and Cell Organisation. 120 recall questions across 10 subtopics.
Where it is assessed
AS Unit 1
Basic Biochemistry and Cell Organisation.
Check the WJEC specification ↗The 10 subtopics
Each one has its own page.
- Inorganic IonsRecall questions on Inorganic Ions.Open →
- Biological Importance of WaterRecall questions on Biological Importance of Water.Open →
- Carbohydrates: Monosaccharides and DisaccharidesRecall questions on Monosaccharides and Disaccharides.Open →
- Carbohydrates: Polysaccharides and Alpha/Beta Glucose IsomerismRecall questions on Polysaccharides and Alpha/Beta Glucose Isomerism.Open →
- Lipids: Triglycerides and PhospholipidsRecall questions on Triglycerides and Phospholipids.Open →
- Lipids: Saturated and Unsaturated Fat in Human HealthRecall questions on Saturated and Unsaturated Fat in Human Health.Open →
- Amino Acids and Proteins: Primary to Quaternary StructureRecall questions on Primary to Quaternary Structure.Open →
- Amino Acids and Proteins: Fibrous and Globular FormsRecall questions on Fibrous and Globular Forms.Open →
- Condensation and Hydrolysis: Peptide and GlycosidicRecall questions on Peptide and Glycosidic.Open →
- Food Tests for Biological MoleculesBenedict's test for reducing and non-reducing sugars, the biuret and emulsion tests, why each step is done, making Benedict's semi-quantitative, the controls and safety precautions, and interpreting results.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Process
How does the polarity of water molecules explain hydrogen bonding, surface tension and the behaviour of lipids in water?
Numbers
Why is sucrose, rather than glucose, the sugar transported in the phloem?
Key term
Two polysaccharides are both made of glucose, yet one is a food store and the other is structural. How is this possible?
Key term
What makes a fatty acid saturated, monounsaturated or polyunsaturated, and which parts of a phospholipid are hydrophilic and hydrophobic?
Key term
Name the bond that joins two amino acids, the groups that react to form it, and the bond that joins a fatty acid to glycerol.
Numbers
How many water molecules are involved in hydrolysing a 500-unit polysaccharide, in forming a 100-amino-acid polypeptide, and in forming one triglyceride?
Key term
How is the Benedict's test for a reducing sugar carried out?
Key term
Give the molecular formula of glucose.
Key term
Which elements are found in a triglyceride?
Key term
What makes one amino acid different from another?
Process
Distinguish between a dipeptide and a polypeptide.
Key term
How is the biuret test for protein carried out?
Key term
A food sample gives a purple colour with biuret reagent and a brick-red precipitate with Benedict's. What does this tell you?
Key term
Name four inorganic ions essential to living organisms and give one role of each.
Key term
Why do lipids not dissolve in water?
Key term
Which bonds are found in amylopectin?
Key term
Why are triglycerides a better long-term store than an equivalent mass of carbohydrate in terms of water balance?
Key term
Distinguish between the roles of low-density and high-density lipoproteins.
Key term
What is a prosthetic group, and what is a protein containing one called?
Key term
Why are globular proteins soluble in water?
Key term
What is the main biological role of the magnesium ion in plants?
Key term
Which type of reaction releases water as a product?
Key term
Which three elements are present in every carbohydrate?
Key term
How does the structure of glycogen differ from that of starch?
Key term
State the components of a triglyceride.
Key term
What is the effect of replacing saturated fat in the diet with unsaturated fat?
Key term
What is the general structure of an amino acid?
Key term
A single amino acid in a polypeptide is replaced by one with a very different R group. Suggest the consequence.
Key term
A sugar solution gives a negative Benedict's test. How would you test whether it contains a non-reducing sugar?
Take Chemical Elements Are Joined Together to Form Biological Compounds further
The same content, four other ways.
Questions from this topic
Each one with the model answer underneath.
- 1
Name four inorganic ions essential to living organisms and give one role of each.
Model answer
Magnesium (Mg²⁺) is part of the chlorophyll molecule; iron (Fe²⁺) is part of haem in haemoglobin, which carries oxygen; calcium (Ca²⁺) strengthens bones and teeth in animals and forms calcium pectate in plant cell walls; and phosphate (PO₄³⁻) is used to make ATP, nucleic acids and phospholipids.
- 2
What is the main biological role of the magnesium ion in plants?
Model answer
Mg²⁺ is a constituent of the chlorophyll molecule, so it is essential for photosynthesis.
- 3
Why does a plant grown in a magnesium-deficient solution develop yellow leaves?
Model answer
Without Mg²⁺ the plant cannot make enough chlorophyll, so the leaves lose their green colour (chlorosis) and the rate of photosynthesis falls.
- 4
Why is the iron ion essential in mammals?
Model answer
Fe²⁺ forms part of the haem group of haemoglobin, which binds and transports oxygen.
- 5
Give one role of calcium ions in plants and one in animals.
Model answer
In plants Ca²⁺ forms calcium pectate in the middle lamella, sticking adjacent cell walls together; in animals it is a component of bones and teeth.
- 6
State three biological molecules that contain the phosphate ion.
Model answer
Phosphate (PO₄³⁻) is found in nucleotides such as DNA and RNA, in ATP and in phospholipids.
What is inside Levo
Six ways to work the same material.
Chemical Elements Are Joined Together to Form Biological Compounds revision questions
- What does Chemical Elements Are Joined Together to Form Biological Compounds cover in WJEC A-Level Biology?
- 10 subtopics: inorganic ions, biological importance of water, carbohydrates: monosaccharides and disaccharides, carbohydrates: polysaccharides and alpha/beta glucose isomerism, lipids: triglycerides and phospholipids, lipids: saturated and unsaturated fat in human health, amino acids and proteins: primary to quaternary structure, amino acids and proteins: fibrous and globular forms, condensation and hydrolysis: peptide and glycosidic and food tests for biological molecules. Each one has its own page with questions and model answers.
- How is Chemical Elements Are Joined Together to Form Biological Compounds organised?
- By the WJEC 601-5290-0 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Chemical Elements Are Joined Together to Form Biological Compounds, 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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