Key term
OCR A-Level Biology B H422
The Developing Cell: Cell Division and Cell Differentiation
The Developing Individual: Meiosis, Growth and Development
The Development of Species: Evolution and Classification
Cells and Microscopy
Topic overviewMicroscopy and the cell theoryBlood smears, staining and microscope drawingsBlood cells and their structureMagnification and measuring cellsHaemocytometer cell counts and dilutionsFlow cytometry in blood analysisUltrastructure of the animal cellPlant and prokaryotic cellsMembrane lipids and the fluid mosaic modelMovement of molecules across membranesThe roles of membranes and the secretion of proteins
Water and Its Importance in Plants and Animals
Proteins and Enzymes
Nucleic Acids
Patterns of Inheritance
Population Genetics and Epigenetics
Gene Technologies
The Principles and Importance of Homeostasis
The Hormonal Control of Blood Glucose and the Management of Diabetes
Kidney Functions and Malfunctions
Topic overviewExcretion and the gross structure of the kidneyThe nephron: ultrafiltration and selective reabsorptionInvestigating the composition of urine, plasma and filtrateOsmoregulation and the action of ADHThe kidney as an endocrine gland and kidney failureDialysis, transplantation and the future of transplant surgery
The Cellular Basis of Cancer and Treatment
Respiratory Diseases and Treatment
Cellular Respiration
Metabolism and Exercise
Topic overviewThe consequences of exercise on the bodyAerobic fitness and VO₂ maxTraining, F.I.T.T. factors and investigating fitnessEnhancing athletic performanceHaemoglobin and the transport of oxygenOxygen dissociation curves of different respiratory pigmentsOxygen deficit and oxygen debtThe structure of skeletal muscleThe sliding filament theory of muscle contraction
Pathogenic Microorganisms
The Immune System
Controlling Communicable Diseases
Photosynthesis, Food Production and Management of the Environment
Topic overviewChloroplast ultrastructure and photosynthetic pigmentsThe light-dependent stage of photosynthesisThe Calvin cycleInvestigating the factors affecting photosynthesisThe Hill reaction and DCPIPUsing TP and GP to build carbohydrates, lipids and amino acidsThe compensation point and crop productionMicroorganisms, the nitrogen cycle and biosensorsBiomass transfer and efficiency in food productionRuminants in the human food chainFarms as ecosystems and the conflict with conservationDeflected succession and measuring biodiversity
The Impact of Population Increase
Planning and Implementing Practical Work
Analysing and Evaluating Practical Results
Practical Skills, Apparatus and Techniques
Topic overviewInvestigative approaches and working safelyFollowing instructions, recording and presenting dataResearch, referencing and processing data with softwareMeasuring mass, volume, time, temperature, length and pHColorimeters and potometersLaboratory glassware and serial dilutionsLight microscopy, graticules and biological drawingQualitative reagents for biological moleculesChromatography and electrophoresisAseptic technique and dissectionWhole-organism responses, fieldwork sampling and data logging
Fertility and Assisted Reproduction
The Effects of Ageing on the Reproductive System
Plant Reproduction
The Nervous System and the Identification and Consequences of Damage
Topic overviewOrganisation of the nervous system and nervous tissueThe structure and function of the human brainThe structure of motor, sensory and relay neuronesResting potential and the action potentialSynapses and the integration of responsesReflexes, reaction times and their investigationBrain scans and the consequences of nervous system damageDrugs, brain function and dependency
Monitoring Visual Function
The Effect of Ageing on the Nervous System
The Heart and Monitoring Heart Function
Transport Systems in Mammals
Gas Exchange in Mammals and Plants
Practical Skills, Apparatus and Techniques
- 11 subtopics
- 33 things to know
- Components 01, 02 and 03
What Practical Skills, Apparatus and Techniques covers
Practical Skills, Apparatus and Techniques is examined in all three written papers — the specification states that Components 01, 02 and 03 can each assess content from any of the five modules, so nothing is confined to one paper. It covers investigative approaches and working safely, following instructions, recording and presenting data, research, referencing and processing data with software, measuring mass, volume, time, temperature, length and pH, Colorimeters and potometers, laboratory glassware and serial dilutions, light microscopy, graticules and biological drawing, qualitative reagents for biological molecules, chromatography and electrophoresis, aseptic technique and dissection and whole-organism responses, fieldwork sampling and data logging.
Where it is assessed
Components 01, 02 and 03
Every module can be assessed on any of the three papers.
Check the OCR specification ↗The 11 subtopics
Each one has its own page.
- Investigative approaches and working safelyRecall questions on taking an investigative approach, testing antiseptics on agar with a control disc, hazard and risk, the steps of a risk assessment, handling ethanol, sodium hydroxide, spilled cultures, scalpels and fresh liver safely, and the ethical treatment of invertebrates and human volunteers.Open →
- Following instructions, recording and presenting dataRecall questions on reading and following a method, exact and approximate volumes, recording observations immediately and honestly, drawing results tables in advance, presenting food test results, keeping raw data, the benefits and risks of spreadsheets, graph titles, histograms and frequency tables.Open →
- Research, referencing and processing data with softwareRecall questions on primary and secondary sources, peer review, judging the reliability, date and bias of a source and its funding, citing journal articles and web pages, in-text citations, plagiarism, computer modelling of molecules, and statistical software.Open →
- Measuring mass, volume, time, temperature, length and pHRecall questions on taring a balance, choosing apparatus for an accurate volume, parallax error, timing uncertainty, measuring pH precisely, and holding a mixture at a set temperature.Open →
- Colorimeters and potometersRecall questions on zeroing a colorimeter and choosing its filter, building and reading a calibration curve, handling a cuvette, beetroot membrane work, and why potometer uptake overestimates transpiration.Open →
- Laboratory glassware and serial dilutionsRecall questions on tenfold serial dilutions and doubling dilutions, calculating concentrations and the volumes needed, mixing and using fresh pipettes, volumetric flasks and making up a standard solution, reading a meniscus, dilution factors, and viable counts in colony-forming units.Open →
- Light microscopy, graticules and biological drawingRecall questions on using objective lenses, focus and the iris diaphragm, field of view and total magnification, calibrating an eyepiece graticule with a stage micrometer and measuring cells, the magnification of a drawing, drawing conventions, low power plans and high power drawings, and labels and annotations.Open →
- Qualitative reagents for biological moleculesRecall questions on the iodine test for starch, the Benedict's test for reducing sugars and its colour sequence, testing for non-reducing sugars such as sucrose, the biuret test for protein, the emulsion test for lipids, DCPIP for vitamin C, and negative controls.Open →
- Chromatography and electrophoresisRecall questions on stationary and mobile phases, thin-layer and paper chromatography technique, calculating and using Rf values, locating amino acids with ninhydrin, loading dye in gels, and how gel electrophoresis separates DNA fragments by size and charge.Open →
- Aseptic technique and dissectionRecall questions on aseptic technique, flaming loops and bottle necks, working near a Bunsen flame, lifting, taping and labelling Petri dishes, autoclaving and disposing of cultures, colony-forming units, spreading a lawn for antibiotic discs, and the safety and ethics of dissecting a mammalian heart.Open →
- Whole-organism responses, fieldwork sampling and data loggingRecall questions on choice chamber investigations, measuring pulse rate and recovery time after exercise, random quadrat sampling and belt transects, percentage cover and frequency, mark-release-recapture and its assumptions, and the advantages of data loggers.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
Describe the mark-release-recapture method of estimating the size of an animal population.
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A student is asked to find which of four antiseptics is most effective against a bacterium. Outline the approach they would take.
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What is the difference between an instruction to add 5 cm³ and one to add approximately 5 cm³?
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Distinguish between a primary and a secondary source of scientific information.
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Which instrument is used to measure the mass of a sample of plant tissue, and to what resolution would you expect to work?
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How is the filter for a colorimeter chosen?
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State the order in which the objective lenses are used when a slide is examined.
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Which reagent tests for starch, and what colour change shows a positive result?
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Name the stationary phase and the mobile phase in paper chromatography.
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Why is an inoculating loop held in a Bunsen flame until it glows red?
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Define the term hazard.
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Why must observations be recorded at the moment they are made rather than written up afterwards?
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Why is a peer-reviewed journal article a more reliable source than a personal blog?
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Why is plant tissue blotted dry before its mass is recorded in an osmosis investigation?
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Which colour filter would you select for measuring the absorbance of a red solution?
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How is a tenfold serial dilution prepared from a stock solution?
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Why is the coarse focus never used with the high power objective?
Process
State the sequence of colours seen in a positive Benedict's test as the concentration of reducing sugar increases.
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Why is the origin line of a paper chromatogram drawn in pencil rather than ink?
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Why is a flamed loop allowed to cool before it touches a culture?
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State two variables that must be controlled in a choice-chamber investigation of humidity.
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Define the term risk.
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What should be recorded in a practical account alongside the numerical readings?
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Why should the date of a source be considered when researching a medical treatment?
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Which apparatus gives the most accurate measurement of 25.00 cm³ of a solution: a beaker, a measuring cylinder or a pipette?
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Why must the same filter be used for every reading within one investigation?
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How would you make 10 cm³ of a solution ten times more dilute than the stock?
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How is the field of view brightened when the microscope is switched from low to high power?
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Name two reducing sugars that give a positive Benedict's test.
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Why must the origin line be above the level of the solvent in the tank?
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Why is microbiological work carried out close to a lit Bunsen burner?
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Why is the same number of organisms placed in each half of a choice chamber at the start?
Take Practical Skills, Apparatus and Techniques further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Hazard vs Risk
Hazard: anything with the potential to cause harm, such as a corrosive reagent, a naked flame or a sharp blade. Risk: the likelihood that harm will actually be caused in the way something is being used, together with how serious that harm would be.
Reducing sugar vs Non-reducing sugar
Reducing sugar: a sugar such as glucose or maltose that gives a positive result with Benedict's solution straight away. Non-reducing sugar: a sugar such as sucrose that gives no colour change until it has been boiled with acid to hydrolyse it and then neutralised.
Eyepiece graticule vs Stage micrometer
Eyepiece graticule: the arbitrary scale on a disc inside the lens the observer looks through, whose divisions must be calibrated before they can measure anything. Stage micrometer: a slide carrying an accurately ruled scale of known size, commonly 1 mm divided into 100 divisions of 10 μm, used to calibrate the measuring scale.
Questions from this topic
Each one with the model answer underneath.
- 1
What is meant by an investigative approach to a practical problem?
Model answer
It means planning and carrying out an experiment to answer a specific question, choosing the variables, apparatus and method to suit the problem rather than following a recipe.
- 2
A student is asked to find which of four antiseptics is most effective against a bacterium. Outline the approach they would take.
Model answer
Discs soaked in equal volumes of each antiseptic are placed on an evenly inoculated agar plate, and the diameter of the clear zone around each disc is measured after incubation.
- 3
In an investigation using antiseptic-soaked discs on an inoculated agar plate, what should the control disc contain?
Model answer
It should be soaked in sterile distilled water, or in the solvent used for the antiseptics, so that it carries no antiseptic.
- 4
Define the term hazard.
Model answer
A hazard is anything with the potential to cause harm.
- 5
Define the term risk.
Model answer
Risk is the likelihood that a hazard will actually cause harm, together with how serious that harm would be.
- 6
State the steps of a risk assessment for a practical activity.
Model answer
The hazards are identified, the people who could be harmed and the seriousness of the harm are considered, and a control measure is given for each hazard.
What is inside Levo
Six ways to work the same material.
Practical Skills, Apparatus and Techniques revision questions
- What does Practical Skills, Apparatus and Techniques cover in OCR A-Level Biology B?
- 11 subtopics: investigative approaches and working safely, following instructions, recording and presenting data, research, referencing and processing data with software, measuring mass, volume, time, temperature, length and ph, colorimeters and potometers, laboratory glassware and serial dilutions, light microscopy, graticules and biological drawing, qualitative reagents for biological molecules, chromatography and electrophoresis, aseptic technique and dissection and whole-organism responses, fieldwork sampling and data logging. Each one has its own page with questions and model answers.
- How is Practical Skills, Apparatus and Techniques organised?
- By the OCR H422 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Practical Skills, Apparatus and Techniques, 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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