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
Plant Reproduction
- 4 subtopics
- 12 things to know
- Components 01, 02 and 03
What Plant Reproduction covers
Plant Reproduction 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 the control of flowering, adaptations of flowers for pollination, fertilisation, seed formation and germination and cereals as staple foods.
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 4 subtopics
Each one has its own page.
- The control of floweringRecall questions on vernalisation and the crops needing it, the pigment that measures day length and its two forms, night interruption experiments, and how growers exploit photoperiodism.Open →
- Adaptations of flowers for pollinationRecall questions on pollination and fertilisation, how the anthers, stigmas and pollen of wind-pollinated flowers are adapted, why they lack petals, scent and nectar, how insect-pollinated flowers attract pollinators with nectar guides, pollination of a pea flower by a bee, and dissecting a flower.Open →
- Fertilisation, seed formation and germinationRecall questions on pollen tube growth and male gametes, double fertilisation and the endosperm, the plumule, radicle and cotyledons, the testa, endospermic and non-endospermic seeds, conditions for germination, gibberellin and amylase in cereal grains, and investigating germination.Open →
- Cereals as staple foodsRecall questions on staple foods and why rice, wheat and maize dominate, starch in the endosperm, the nutritional risks of a single-cereal diet and milling, combining cereals with legumes, threats to cereal-based food security, the environmental costs of intensive growing, seed banks, and sustainable practices.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
Describe double fertilisation in a flowering plant.
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Which three external conditions are required for germination, and why is water needed?
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How does gibberellin act as a cell signalling molecule in a germinating cereal grain?
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Why is a diet based almost entirely on one cereal nutritionally risky?
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What is removed when wheat is milled into white flour or rice is polished, and why does it matter?
Evaluation
Name a crop that requires vernalisation and explain the advantage of the requirement.
Key term
Outline how prolonged cold makes a plant competent to flower.
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Distinguish between pollination and fertilisation in a flowering plant.
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How can a winter cereal variety be sown in spring?
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Why do wind-pollinated flowers have no large petals, no scent and no nectar?
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Which three cereals dominate the world food supply, and where is each the main staple?
Take Plant Reproduction further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Pollination vs Fertilisation
Pollination: the transfer of a grain from an anther onto the stigma of a flower. Fertilisation: the fusion of a male gamete delivered by the pollen tube with the female gamete inside the ovule.
Pr vs Pfr
Pr: the inactive form of phytochrome, which absorbs red light of about 660 nm and is converted by it into the active form. Pfr: the physiologically active form of phytochrome, which absorbs far-red light and slowly reverts to the inactive form in darkness.
Long-day plant vs Short-day plant
Long-day plant: a species brought into flower by brief nights, because a high concentration of the active form of phytochrome promotes flowering. Short-day plant: a species that flowers only when the uninterrupted dark period is extended enough for the active form of phytochrome to fall low and stop inhibiting flowering.
Questions from this topic
Each one with the model answer underneath.
- 1
What is vernalisation?
Model answer
It is the requirement for a prolonged period of low temperature before a plant becomes able to flower.
- 2
Name a crop that requires vernalisation and explain the advantage of the requirement.
Model answer
Winter wheat requires it; because it will not flower until it has been through a cold winter, it cannot flower in the autumn when the seedlings emerge, and instead flowers and sets seed in the favourable conditions of the following summer.
- 3
Outline how prolonged cold makes a plant competent to flower.
Model answer
Weeks of low temperature sensed at the shoot apical meristem progressively switch off a gene whose product represses flowering, and that switched-off state is inherited by the cells produced as the meristem divides, so after the winter the plant is able to respond to the flowering signal.
- 4
How can a winter cereal variety be sown in spring?
Model answer
The moistened seed is chilled artificially for several weeks before sowing, which supplies the cold requirement so the plant will flower that year.
- 5
What is photoperiodism?
Model answer
It is the response of a plant, such as the timing of its flowering, to the relative lengths of day and night.
- 6
Which pigment do plants use to measure day length, and what are its two interconvertible forms?
Model answer
Phytochrome, which exists as Pr and Pfr.
What is inside Levo
Six ways to work the same material.
Plant Reproduction revision questions
- What does Plant Reproduction cover in OCR A-Level Biology B?
- 4 subtopics: the control of flowering, adaptations of flowers for pollination, fertilisation, seed formation and germination and cereals as staple foods. Each one has its own page with questions and model answers.
- How is Plant Reproduction organised?
- By the OCR H422 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Plant Reproduction, 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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