Process
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
Planning and Implementing Practical Work
- 3 subtopics
- 12 things to know
- Components 01, 02 and 03
What Planning and Implementing Practical Work covers
Planning and Implementing Practical Work 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 Designing an investigation and controlling variables, choosing apparatus and judging whether a method will work and Implementing: apparatus, units and recording results.
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 3 subtopics
Each one has its own page.
- Designing an investigation and controlling variablesRecall questions on independent, dependent and control variables, holding temperature and pH constant in enzyme work, control experiments, continuous and categoric variables, repeats and ranges, null hypotheses, preliminary experiments, allowing for individual differences between subjects, and validity.Open →
- Choosing apparatus and judging whether a method will workRecall questions on the resolution of instruments and choosing pipettes, gas syringes, colorimeters, water baths and data loggers, setting a sensible range, adjusting a reaction that is too fast, reproducibility and equilibration, preliminary trials, assembling a potometer, and writing a safe method.Open →
- Implementing: apparatus, units and recording resultsRecall questions on units and conversions for concentration, volume, length and rate, expressing respirometer rates per gram, heading and ordering results table columns, consistent decimal places, raw and processed data, choosing bar charts, line graphs or scattergrams, and reading burettes and menisci.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Evaluation
What makes an investigation's results reliable and its method valid?
Evaluation
Which apparatus collects a gas and holds a reaction at temperature, and what should be done if a reaction is too fast?
Key term
Which graph suits a categoric independent variable, which suits two continuous variables, and when is a scattergram used instead?
Key term
Which apparatus would you select to measure the volume of oxygen released by pondweed over ten minutes?
Key term
State the unit, with its symbol, in which the concentration of a solution is normally expressed in biology.
Key term
Name three variables that must be controlled when investigating the effect of substrate concentration on the rate of an enzyme-controlled reaction.
Key term
State the apparatus you would use to hold a reaction mixture at 35 °C.
Key term
Convert 0.045 dm³ to cubic centimetres.
Key term
How is temperature held constant in an enzyme investigation?
Key term
A trial run produces a colour change that is complete within two seconds at every concentration tested. What should the investigator do?
Key term
A leaf loses 0.60 g of water in 30 minutes. State the rate of water loss in g h⁻¹.
Take Planning and Implementing Practical Work further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Control variable vs Control experiment
Control variable: a factor deliberately held constant throughout an investigation, so that any change in what is measured can be attributed to the one factor being altered. Control experiment: a whole extra run of the procedure with the factor under test removed or inactivated, used as the baseline the test run is compared against.
Valid vs Reliable
Valid: measuring what the investigation set out to measure, because every other factor that could affect the outcome has been controlled. Reliable: giving the same result each time the procedure is repeated, so the measurements are consistent.
Resolution vs Accuracy
Resolution: the smallest change in a quantity that an instrument is able to detect, set by the size of its scale divisions. Accuracy: closeness to the true value, which a finely divided but badly calibrated instrument can still fail to achieve.
Questions from this topic
Each one with the model answer underneath.
- 1
What is meant by the independent variable in an investigation?
Model answer
It is the variable the investigator deliberately changes, or whose values they select.
- 2
Define the term dependent variable.
Model answer
It is the variable that is measured, because it responds to changes in the independent variable.
- 3
Why must control variables be kept constant throughout an investigation?
Model answer
So that any change in the dependent variable can be attributed only to the independent variable, which makes the conclusion valid.
- 4
Name three variables that must be controlled when investigating the effect of substrate concentration on the rate of an enzyme-controlled reaction.
Model answer
Temperature, pH and enzyme concentration must all be kept constant.
- 5
How is temperature held constant in an enzyme investigation?
Model answer
The reaction vessels are held in a thermostatically controlled water bath and left to equilibrate before the reactants are mixed.
- 6
Why is a buffer solution added to an enzyme reaction mixture?
Model answer
It resists changes in pH, so pH cannot act as a second variable affecting the activity of the enzyme.
What is inside Levo
Six ways to work the same material.
Planning and Implementing Practical Work revision questions
- What does Planning and Implementing Practical Work cover in OCR A-Level Biology B?
- 3 subtopics: designing an investigation and controlling variables, choosing apparatus and judging whether a method will work and implementing: apparatus, units and recording results. Each one has its own page with questions and model answers.
- How is Planning and Implementing Practical Work organised?
- By the OCR H422 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Planning and Implementing Practical Work, 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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