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
Biological Molecules
- 10 subtopics
- 30 things to know
- Unit AS 1
What Biological Molecules covers
Biological Molecules is examined in Unit AS 1, Molecules and Cells, and drawn on again in Unit AS 3, the practical skills examination. It covers water as a solvent, inorganic ions and their roles, monosaccharides and the glycosidic bond, Disaccharides and polysaccharides, lipids, triglycerides and phospholipids, amino acids and protein structure, protein shape, conjugated proteins and prions, nucleic acids: nucleotides, DNA and RNA, DNA replication and the Meselson–Stahl experiment and biochemical tests and paper chromatography.
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 10 subtopics
Each one has its own page. CCEA AS Biology students sit this topic in the first year.
- Water as a solventBond forms between neighbouring water molecules, watery liquid that carries dissolved substances around a mammal's body and why water is a reactant and not only a solvent.Open →
- Inorganic ions and their rolesCalcium compound that cements neighbouring plant cell walls together, role of phosphate ions in ATP and role of phosphate ions in nucleic acids.Open →
- Monosaccharides and the glycosidic bondTerm monosaccharide, why α-glucose and β-glucose are described as isomers and hexose sugar of fruit that shares the formula of glucose.Open →
- Disaccharides and polysaccharidesHow β-glucose molecules are arranged along a cellulose chain, how cellulose chains are held together in a microfibril and two polymers that make up starch.Open →
- Lipids, triglycerides and phospholipidsTwo kinds of molecule that condense to form a triglyceride, bond that joins a fatty acid to glycerol and difference between a fat and an oil.Open →
- Amino acids and protein structureReaction joins two amino acids, primary structure of a protein and two forms of secondary structure found in proteins.Open →
- Protein shape, conjugated proteins and prionsGeneral shape of a fibrous protein, fibrous protein that gives tendons and skin their tensile strength and structure of a collagen molecule.Open →
- Nucleic acids: nucleotides, DNA and RNAThree components of a nucleotide, reaction assembles a nucleotide from its three components and pentose sugar found in DNA.Open →
- DNA replication and the Meselson–Stahl experimentRecall questions on semi-conservative replication and the roles of helicase and DNA polymerase, the heavy nitrogen isotope and density gradient centrifugation, what the first and second generations showed, and how each result ruled out the conservative and dispersive models.Open →
- Biochemical tests and paper chromatographyReagent and the positive result for the test for starch, how a reducing sugar is detected and how a non-reducing sugar such as sucrose is detected.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
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How does a fibrous protein differ from a globular one, and what does each kind do?
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Why is a water molecule described as polar?
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Which inorganic ion sits at the centre of a chlorophyll molecule?
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Give the molecular formula of glucose.
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Which monosaccharides condense to form maltose?
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Name the two kinds of molecule that condense to form a triglyceride.
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Name the four groups attached to the central carbon atom of an amino acid.
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Name the three components of a nucleotide.
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State the reagent and the positive result for the test for starch.
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What kind of bond forms between neighbouring water molecules?
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Which inorganic ion is held within the haem group of haemoglobin?
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Define the term monosaccharide.
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Which monosaccharides condense to form sucrose?
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Name the bond that joins a fatty acid to glycerol.
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Which part of an amino acid differs from one amino acid to another?
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Describe the general shape of a fibrous protein.
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What type of reaction assembles a nucleotide from its three components?
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What does it mean to say that DNA replication is semi-conservative?
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Describe how a reducing sugar is detected.
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Which kinds of substance fail to dissolve in water?
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Name the calcium compound that cements neighbouring plant cell walls together.
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Name the hexose sugar of fruit that shares the formula of glucose.
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Which monomer is polymerised to build cellulose?
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How many molecules of water are released when one triglyceride is formed?
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What type of reaction joins two amino acids, and what is released?
Evaluation
Name the fibrous protein that gives tendons and skin their tensile strength.
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What kind of bond links one nucleotide to the next in a polynucleotide chain?
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Name the enzyme that opens the DNA helix at the start of replication.
Process
Describe the sequence of colours seen with Benedict's solution as reducing sugar concentration rises.
Take Biological Molecules further
The same content, four other ways.
Questions from this topic
Each one with the model answer underneath.
- 1
Why is a water molecule described as polar?
Model answer
The oxygen atom attracts the shared electrons more strongly than the hydrogen atoms, so the oxygen carries a small negative charge and each hydrogen carries a small positive charge.
- 2
What kind of bond forms between neighbouring water molecules?
Model answer
A hydrogen bond forms between the slightly positive hydrogen of one molecule and the slightly negative oxygen of another.
- 3
Explain why an ionic solid such as sodium chloride dissolves readily in water.
Model answer
Polar water molecules cluster around each ion and are attracted to its charge, pulling the ions away from the lattice and holding them in solution.
- 4
Which kinds of substance fail to dissolve in water?
Model answer
Non-polar substances such as lipids do not dissolve, because they cannot form attractions with polar water molecules.
- 5
Why does the solvent property of water matter for metabolism?
Model answer
Almost every metabolic reaction takes place in solution, so dissolved reactants are free to move and collide in the cytoplasm.
- 6
Name the watery liquid that carries dissolved substances around a mammal's body.
Model answer
Blood plasma is the aqueous liquid in which glucose, amino acids, ions and urea are transported.
What is inside Levo
Six ways to work the same material.
Biological Molecules revision questions
- Is Biological Molecules 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 Biological Molecules cover in CCEA AS-Level Biology?
- 10 subtopics: water as a solvent, inorganic ions and their roles, monosaccharides and the glycosidic bond, disaccharides and polysaccharides, lipids, triglycerides and phospholipids, amino acids and protein structure, protein shape, conjugated proteins and prions, nucleic acids: nucleotides, dna and rna, dna replication and the meselson–stahl experiment and biochemical tests and paper chromatography. Each one has its own page with questions and model answers.
- How is Biological Molecules organised?
- By the CCEA 1010 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Biological Molecules, 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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