Key term
Eduqas A-Level Biology A400QS
Biological Molecules
Cell Structure and Organisation
Cell Membranes and Transport
Enzymes
Nucleic Acids and Their Functions
Importance of ATP
Photosynthesis
Respiration
Microbiology
Population Size and Ecosystems
Topic overviewPopulation growth and its measurementThe population growth curve and carrying capacityDensity dependent and density independent factorsSampling abundance and distributionEcosystems, habitats and communitiesEnergy transfer and pyramids of biomassSuccessionDecomposition and the carbon cycleThe nitrogen cycle and human interventionEutrophication and the effects of drainage
Human Impact on the Environment
Classification and Biodiversity
Topic overviewThe need for classification and the taxonomic hierarchyThe three domain and five kingdom systemsCharacteristic features of the five kingdomsAssessing relatedness by physical features and biochemistryThe species concept and the binomial systemBiodiversity, adaptation and natural selectionMeasuring biodiversity in a habitatGenetic and molecular measures of biodiversity
Mitosis and Meiosis
Sexual Reproduction in Humans
Sexual Reproduction in Plants
Inheritance
Variation and Evolution
Application of Reproduction and Genetics
Topic overviewThe Human Genome Project, other sequenced genomes and genomics in healthcareScreening embryos, stem cells and the ethical issuesGenetic fingerprinting, PCR and electrophoresis in forensic workRecombinant DNA and the production of human insulinGenetically modified crops and gene therapy
Adaptations for Gas Exchange
Topic overviewSurface area to volume ratio and gas exchange in small organismsSpecialised respiratory surfaces and the need for ventilationGills and counter current flow in bony fishThe human breathing system and its histologyVentilation and gas exchange in humansThe insect tracheal systemThe angiosperm leaf, stomata and gas exchange
Adaptations for Transport
Topic overviewVascular systems compared across animal groupsThe mammalian heart and blood vesselsThe cardiac cycle and its controlBlood, haemoglobin and dissociation curvesThe Bohr effect, chloride shift and tissue fluidThe root and the uptake of waterThe endodermis and the entry to the xylemXylem, transpiration and cohesion-tensionThe potometer and xerophytes and hydrophytesPhloem and translocation
Adaptations for Nutrition
Homeostasis and the Kidney
The Nervous System
Immunology and Disease: Disease and Its TransmissionImmunology
Immunology and Disease: AntibioticsImmunology
Immunology and Disease: The Immune ResponseImmunology
Human Musculoskeletal Anatomy: Skeletal TissuesMusculoskeletal
Topic overviewCartilage and its three typesThe composition and functions of compact boneBone remodelling and the Haversian systemRickets, osteomalacia, osteoporosis and brittle bone diseaseThe structure of skeletal muscleThe sliding filament theoryFast and slow twitch fibres, and energy for contraction
Human Musculoskeletal Anatomy: Structure and Function of the SkeletonMusculoskeletal
Human Musculoskeletal Anatomy: JointsMusculoskeletal
Neurobiology and Behaviour: The BrainNeurobiology
Neurobiology and Behaviour: NeuroscienceNeurobiology
Adaptations for Transport
The potometer and xerophytes and hydrophytes
- 3 things to know
- Component 3
Overview
Three variables that must be controlled in a potometer investigation, four xerophytic adaptations and three hydrophytic adaptations shown by a water lily.
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
Why is the water uptake measured by a potometer only an estimate of transpiration?
Key term
Why is the shoot for a potometer cut and assembled under water?
Questions from this subtopic
Each one with the model answer underneath.
- 1
What does a potometer measure?
Model answer
The rate at which a cut shoot takes up water, which is used as an estimate of the rate of transpiration.
- 2
Why is uptake only an estimate of transpiration?
Model answer
A small proportion of the water taken up is used in photosynthesis and to maintain turgor rather than being lost as vapour.
- 3
Why is the shoot cut and assembled under water?
Model answer
Air drawn into the xylem would break the water column and stop the flow.
- 4
How is the rate calculated from a potometer?
Model answer
The distance the bubble moves is timed, and the volume is found by multiplying that distance by the cross-sectional area of the capillary tube.
- 5
A bubble moves 40 mm in 5 minutes in a tube of radius 0.5 mm. What is the rate of uptake?
Model answer
The cross-sectional area is π times 0.25, about 0.785 mm², so the volume is 31.4 mm³ and the rate is 6.3 mm³ per minute.
- 6
How would you use a potometer to investigate the effect of air movement?
Model answer
Measure the rate with the shoot still, then with a fan at a set distance, keeping temperature, humidity and light the same.
Other ways to work this
The same content, four other ways.
What is inside Levo
Six ways to work the same material.
Every question in Adaptations for 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.
Or £46 a year, about £3.83 a month. Cancel anytime.