Evaluation
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
Choosing apparatus and judging whether a method will work
- 4 things to know
- Components 01, 02 and 03
Overview
Recall 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.
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
Which apparatus would you select to measure the volume of oxygen released by pondweed over ten minutes?
Key term
State the apparatus you would use to hold a reaction mixture at 35 °C.
Key term
A trial run produces a colour change that is complete within two seconds at every concentration tested. What should the investigator do?
Questions from this subtopic
Each one with the model answer underneath.
- 1
What is meant by the resolution of a measuring instrument?
Model answer
It is the smallest change in a quantity that the instrument is able to detect.
- 2
A student must measure 2.0 cm³ of enzyme solution. Explain why a 5 cm³ graduated pipette is a better choice than a 100 cm³ measuring cylinder.
Model answer
The pipette has much smaller scale divisions, so the percentage error in a 2.0 cm³ measurement is far lower.
- 3
Which apparatus would you select to measure the volume of oxygen released by pondweed over ten minutes?
Model answer
A gas syringe, or a graduated capillary tube connected to the apparatus, so the gas is collected and its volume read directly.
- 4
Why is a colorimeter preferred to matching colours by eye when judging the result of a Benedict's test?
Model answer
It gives a numerical absorbance reading, which removes the observer's subjective judgement and makes the result quantitative.
- 5
State the apparatus you would use to hold a reaction mixture at 35 °C.
Model answer
A thermostatically controlled water bath, with a thermometer in the mixture to confirm the temperature.
- 6
Give one reason for choosing a data logger with an oxygen probe rather than a syringe read by hand.
Model answer
It records automatically at fixed intervals, so readings can be taken frequently over a long period without human reaction-time error.
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