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
Tissues and Organs
- 7 subtopics
- 21 things to know
- Unit AS 1
What Tissues and Organs covers
Tissues and Organs is examined in Unit AS 1, Molecules and Cells, and drawn on again in Unit AS 3, the practical skills examination. It covers tissues and organs, the tissue layers of the ileum, the mucosa, villi and crypts of Lieberkühn, adaptations of the ileum for absorption, the mesophytic leaf and its epidermal layers, palisade and spongy mesophyll and leaf vascular tissue and stomata.
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.
- Tissues and organsTerm tissue, term organ and plant organ whose overall function is photosynthesis.Open →
- The tissue layers of the ileumRole of the muscularis mucosa, why movement of the villi improves absorption and role of the submucosa.Open →
- The mucosa, villi and crypts of LieberkühnEpithelium lines the mucosa of the ileum, function of the goblet cells in the columnar epithelium and main advantage of the villi to the ileum.Open →
- Adaptations of the ileum for absorptionBrush border of the ileum epithelium, part played by diffusion in absorption from the ileum and why active transport is necessary in absorption from the ileum.Open →
- The mesophytic leaf and its epidermal layersMesophytic plant, cells of the upper epidermis and why the upper epidermis is transparent.Open →
- Palisade and spongy mesophyllShape and arrangement of palisade mesophyll cells, advantage of the palisade cells being packed closely together and arrangement of the cells of the spongy mesophyll.Open →
- Leaf vascular tissue and stomataLeaf vein, advantage of veins being branched throughout the leaf and function of the stomata in gas exchange.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
What does a leaf vein contain, and what does each of its tissues do for the leaf?
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Name the five tissue layers of the ileum wall in order from the lumen outwards.
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What type of epithelium lines the mucosa of the ileum?
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What is the brush border of the ileum epithelium?
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Name the tissue layers of a mesophytic leaf in order from the upper surface downwards.
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Where in the leaf is the palisade mesophyll found?
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Define the term tissue.
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Which layer of the ileum wall lines the lumen?
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Which structures on the columnar epithelial cells increase the absorbing surface?
Process
Name the three processes by which the products of digestion are absorbed across the epithelium.
Key term
What is a mesophytic plant?
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Explain why the chloroplasts of a palisade cell can move within it.
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What is a leaf vein?
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Define the term organ.
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State the role of the muscularis mucosa.
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What is the function of the goblet cells in the columnar epithelium?
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Explain the part played by diffusion in absorption from the ileum.
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What covers the outer surface of the upper epidermis?
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Which tissue of the leaf carries out most of its photosynthesis?
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State the role of the xylem within a leaf vein.
Take Tissues and Organs further
The same content, four other ways.
Questions from this topic
Each one with the model answer underneath.
- 1
Define the term tissue.
Model answer
A tissue is an amalgamation of cells that all perform the same function.
- 2
Define the term organ.
Model answer
An organ is a body part composed of several tissues grouped together to perform an overall function.
- 3
Give the levels of organisation between a cell and an organ.
Model answer
Cells of one kind form a tissue, and several tissues grouped together form an organ.
- 4
Name an animal organ whose overall function is the absorption of digested food.
Model answer
The ileum is the organ whose overall function is the absorption of digested food.
- 5
Name a plant organ whose overall function is photosynthesis.
Model answer
The leaf is the plant organ whose overall function is photosynthesis.
- 6
Explain why an epithelium is described as a tissue and not an organ.
Model answer
It is a sheet of cells of one kind performing a single function, rather than several different tissues acting together.
What is inside Levo
Six ways to work the same material.
Tissues and Organs revision questions
- Is Tissues and Organs 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 Tissues and Organs cover in CCEA AS-Level Biology?
- 7 subtopics: tissues and organs, the tissue layers of the ileum, the mucosa, villi and crypts of lieberkühn, adaptations of the ileum for absorption, the mesophytic leaf and its epidermal layers, palisade and spongy mesophyll and leaf vascular tissue and stomata. Each one has its own page with questions and model answers.
- How is Tissues and Organs organised?
- By the CCEA 1010 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Tissues and Organs, 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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