• IB
  • IB Docs (2) Team
    Logout
  • Maths
  • Biology
  • Chemistry
  • Physics
  • Combined Science
  • English Language
  • Geography
  • Other Subjects
GCSE Maths
Edexcel Topic QuestionsRevision NotesPast PapersPast Papers Questions
AQA Topic QuestionsRevision NotesPast Papers
OCR Topic QuestionsRevision NotesPast Papers
GCSE Biology
Edexcel Topic QuestionsRevision NotesPast Papers
AQA Topic QuestionsRevision NotesPast Papers
OCR Gateway Topic QuestionsRevision NotesPast Papers
GCSE Chemistry
Edexcel Topic QuestionsRevision NotesPast Papers
AQA Topic QuestionsRevision NotesPast Papers
OCR Gateway Topic QuestionsRevision NotesPast Papers
GCSE Physics
Edexcel Topic QuestionsRevision NotesPast Papers
AQA Topic QuestionsRevision NotesPast Papers
OCR Gateway Topic QuestionsRevision NotesPast Papers
GCSE Combined Science
Edexcel Combined: Biology Topic QuestionsRevision NotesPast Papers
Edexcel Combined: Chemistry Topic QuestionsRevision NotesPast Papers
Edexcel Combined: Physics Revision NotesPast Papers
AQA Combined: Biology Topic QuestionsRevision NotesPast Papers
AQA Combined: Chemistry Topic QuestionsRevision NotesPast Papers
AQA Combined: Physics Topic QuestionsRevision NotesPast Papers
OCR Gateway Combined: Biology Topic QuestionsRevision Notes
OCR Gateway Combined: Chemistry Revision Notes
OCR Gateway Combined: Physics Revision Notes
GCSE English Language
AQA Revision NotesPractice PapersPast Papers
Edexcel Past Papers
OCR Past Papers
GCSE Geography
AQA Topic QuestionsRevision Notes
Edexcel Topic Questions
GCSE Other Subjects
AQA English LiteratureBusinessComputer ScienceEconomicsFurther MathsGeographyHistoryPsychologySociologyStatistics
Edexcel English LiteratureBusinessComputer ScienceGeographyHistoryPsychologyStatistics
OCR English LiteratureBusinessComputer ScienceEconomicsPsychology
OCR Gateway GeographyHistory
  • Maths
  • Biology
  • Chemistry
  • Physics
  • Double Science
  • Economics
  • English Language
  • Geography
  • Other Subjects
IGCSE Maths
Edexcel Topic QuestionsRevision NotesPast PapersBronze-Silver-Gold Questions
CIE (Extended) Topic QuestionsRevision NotesPast Papers
CIE (Core) Topic QuestionsPast Papers
IGCSE Biology
Edexcel Topic QuestionsRevision NotesPast Papers
CIE 2020-2022 Topic QuestionsRevision NotesPast Papers
CIE 2023-2025 Topic QuestionsRevision NotesPast Papers
IGCSE Chemistry
Edexcel Topic QuestionsRevision NotesPast Papers
CIE 2020-2022 Topic QuestionsRevision NotesPast Papers
CIE 2023-2025 Topic QuestionsRevision NotesPast Papers
IGCSE Physics
Edexcel Topic QuestionsRevision NotesPast Papers
CIE 2020-2022 Topic QuestionsRevision NotesPast Papers
CIE 2023-2025 Topic QuestionsRevision NotesPast Papers
IGCSE Double Science
Edexcel Double: Biology Topic QuestionsRevision NotesPast Papers
Edexcel Double: Chemistry Topic QuestionsRevision NotesPast Papers
Edexcel Double: Physics Topic QuestionsRevision NotesPast Papers
IGCSE Economics
CIE Topic QuestionsRevision NotesPast Papers
IGCSE English Language
CIE Revision NotesPractice PapersPast Papers
Edexcel Past Papers
IGCSE Geography
CIE Revision NotesTopic QuestionsPast Papers
Edexcel Topic QuestionsRevision NotesPast Papers
IGCSE Other Subjects
CIE Additional MathsEnglish LiteratureBusinessComputer ScienceHistorySociology
Edexcel English LiteratureBusinessComputer ScienceHistoryFurther Maths
  • Maths
  • Biology
  • Chemistry
  • Physics
  • English Language
  • Other Subjects
AS Maths
Edexcel Pure MathsMechanicsStatistics
AQA Pure MathsMechanicsStatistics
OCR Pure MathsMechanicsStatistics
CIE Pure 1Pure 2MechanicsProbability & Statistics 1
Edexcel IAS Pure 1Pure 2MechanicsStatistics
AS Biology
AQA Topic QuestionsRevision NotesPast Papers
OCR Topic QuestionsRevision NotesPast Papers
CIE 2019-2021 Topic QuestionsRevision NotesPast Papers
CIE 2022-2024 Topic QuestionsRevision NotesPast Papers
Edexcel IAL Revision Notes
AS Chemistry
Edexcel Revision Notes
AQA Topic QuestionsRevision NotesPast Papers
OCR Revision Notes
CIE 2019-2021 Topic QuestionsRevision NotesPast Papers
CIE 2022-2024 Topic QuestionsRevision NotesPast Papers
Edexcel IAL Revision Notes
AS Physics
Edexcel Revision Notes
AQA Topic QuestionsRevision NotesPast Papers
OCR Revision NotesPast Papers
CIE 2019-2021 Topic QuestionsRevision NotesPast Papers
CIE 2022-2024 Topic QuestionsRevision NotesPast Papers
Edexcel IAL Revision Notes
AS English Language
AQA Past Papers
Edexcel Past Papers
OCR Past Papers
AS Other Subjects
AQA BusinessComputer ScienceEconomicsEnglish LiteratureFurther MathsGeographyHistoryPsychologySociology
Edexcel BusinessEconomicsEnglish LiteratureFurther MathsGeographyHistoryPsychology
OCR BusinessComputer ScienceEconomicsEnglish LiteratureFurther Maths AGeographyHistoryPsychologySociology
CIE Further Maths
  • Maths
  • Biology
  • Chemistry
  • Physics
  • English Language
  • Economics
  • Further Maths
  • Psychology
  • Other Subjects
A Level Maths
Edexcel Pure MathsMechanicsStatistics
AQA Pure MathsMechanicsStatistics
OCR Pure MathsMechanicsStatistics
CIE Pure 1Pure 3MechanicsProbability & Statistics 1Probability & Statistics 2
Edexcel IAL Pure 1Pure 2Pure 3Pure 4Mechanics 1Mechanics 2Statistics 1Statistics 2Decision 1
A Level Biology
Edexcel Topic QuestionsPast Papers
Edexcel A (SNAB) Revision Notes
AQA Topic QuestionsRevision NotesPast Papers
OCR Topic QuestionsRevision NotesPast PapersGold Questions
CIE 2019-2021 Topic QuestionsRevision NotesPast Papers
CIE 2022-2024 Topic QuestionsRevision NotesPast Papers
Edexcel IAL Topic QuestionsRevision NotesPast Papers
A Level Chemistry
Edexcel Topic QuestionsRevision NotesPast Papers
AQA Topic QuestionsRevision NotesPast Papers
OCR Topic QuestionsRevision NotesPast PapersGold Questions
CIE 2019-2021 Topic QuestionsRevision NotesPast Papers
CIE 2022-2024 Topic QuestionsRevision NotesPast Papers
Edexcel IAL Topic QuestionsRevision NotesPast Papers
A Level Physics
Edexcel Topic QuestionsRevision NotesPast Papers
AQA Topic QuestionsRevision NotesPast Papers
OCR Topic QuestionsRevision NotesPast Papers
CIE 2019-2021 Topic QuestionsRevision NotesPast Papers
CIE 2022-2024 Topic QuestionsRevision NotesPast Papers
Edexcel IAL Topic QuestionsRevision NotesPast Papers
A Level English Language
AQA Past Papers
CIE Past Papers
Edexcel Past Papers
OCR Past Papers
Edexcel IAL Past Papers
A Level Economics
Edexcel Topic QuestionsRevision NotesPast Papers
AQA Topic QuestionsPast Papers
OCR Past Papers
CIE Past Papers
A Level Further Maths
Edexcel Topic QuestionsRevision NotesPast Papers
AQA Past Papers
OCR Past Papers
CIE Past Papers
Edexcel IAL Past Papers
A Level Psychology
AQA Topic QuestionsRevision NotesPast Papers
CIE Past Papers
Edexcel Past Papers
OCR Past Papers
Edexcel IAL Past Papers
A Level Other Subjects
AQA BusinessComputer ScienceEconomicsEnglish LiteratureGeographyHistorySociology
CIE BusinessComputer ScienceEconomicsEnglish LiteratureGeographySociology
Edexcel BusinessEconomics AEnglish LiteratureGeographyHistory
OCR BusinessComputer ScienceEconomicsEnglish LiteratureGeographyHistorySociology
Edexcel IAL English LiteratureGeography
CIE IAL History
  • Biology
  • Chemistry
  • Physics
  • Other Subjects
O Level Biology
CIE Topic QuestionsPast Papers
O Level Chemistry
CIE Topic QuestionsPast Papers
O Level Physics
CIE Topic QuestionsPast Papers
O Level Other Subjects
CIE Additional MathsMaths D
  • Maths
  • Biology
  • Chemistry
  • Physics
Pre U Maths
CIE Topic QuestionsPast Papers
Pre U Biology
CIE Topic QuestionsPast Papers
Pre U Chemistry
CIE Topic QuestionsPast Papers
Pre U Physics
CIE Topic QuestionsPast Papers
  • Maths
  • Biology
  • Chemistry
  • Physics
  • Economics
IB Maths
Maths: AA HL Topic QuestionsRevision NotesPractice Papers
Maths: AI HL Topic QuestionsRevision NotesPractice Papers
Maths: AA SL Topic QuestionsRevision NotesPractice Papers
Maths: AI SL Topic QuestionsRevision NotesPractice Papers
IB Biology
Biology: SL Topic QuestionsRevision NotesPractice Papers
Biology: HL Topic QuestionsRevision NotesPractice Papers
IB Chemistry
Chemistry: SL Topic QuestionsRevision NotesPractice Papers
Chemistry: HL Topic QuestionsRevision NotesPractice Papers
IB Physics
Physics: SL Topic QuestionsRevision NotesPractice Papers
Physics: HL Topic QuestionsRevision NotesPractice Papers
IB Economics
Economics: SL Revision Notes

DP IB Biology: SL

Revision Notes

Home / IB / Biology: SL / DP / Revision Notes / 1. Cell Biology / 1.2 Cells: Origin & Ultrastructure / 1.2.1 Origin of Cells


1.2.1 Origin of Cells


Spontaneous Generation

Pre-existing cells

  • In 1852 Robert Remak made the conclusion that cells divided to form new cells, that is cells came from pre-existing cells
  • His conclusion was reached after studying cells from chicken embryos
  • This discovery is often attributed to Robert Virchow who in 1855 proposed the phrase omnis cellula e cellula (all cells come from cells)
  • Prior to these announcements, it was believed that life arose spontaneously from non-living matter

NOS: Testing the general principles that underlie the natural world; the principle that cells only come from pre-existing cells needs to be verified

  • Up until the 17th century, the consensus was that life was spontaneously generated (living organisms arose from non-living matter). This was believed due to:
    • The lack of technology - microscopes were not extensively used
    • Observations being made - Aristotle observing insects forming from dew or van Helmont observing a mouse appearing from a jar containing a sweaty shirt and wheat
    • The idea supporting the cultural and religious beliefs of the time

  • From the 17th century scientists such as Francesco Redi with his maggot and rotting meat experiment began collecting evidence to test and verify that life required life to exist
  • However, it was Louis Pasteur's experiments involving swan-neck flasks that provided sufficient verification to convince scientists that cells could only come from pre-existing cells
  • The universal acceptance that cells come from pre-existing cells also comes from the idea that :
    • The highly complex ultrastructure of cells has not been able to be synthesised by humans
    • All the known examples of growth are a result of cells dividing by mitosis or meiosis
    • Although viruses have a much simpler structure, they can only be produced inside a host cell
    • The universality of the genetic code suggests that all life evolved from the same original cells
      • The translation of the 64 codons produces the same amino acids for nearly all organisms - although there are some rare minor variations that have likely arisen since the common origin of life

Experiments disproving spontaneous generation 1, downloadable IB Biology revision notesExperiments disproving spontaneous generation 2, downloadable IB Biology revision notesExperiments disproving spontaneous generation 3, downloadable IB Biology revision notesExperiments disproving spontaneous generation 4, downloadable IB Biology revision notesExperiments disproving spontaneous generation 5, downloadable IB Biology revision notesExperiments disproving spontaneous generation 6, downloadable IB Biology revision notes

Experiments disproving spontaneous generation

Pasteur's Experiments

Louis Pasteur's experiments

  • Louis Pasteur's experiments were designed to verify the principle that cells can only come from pre-existing cells
  • To demonstrate this Pasteur used swan neck flasks (flasks with S-shaped necks) which trapped the microorganisms in the bend of the neck
  • Pasteur added nutrient broth to the flasks then boiled them to sterilise
  • With some of the flasks, Pasteur broke off the necks (leaving no bend)
  • After a long period of time, Pasteur observed that the broth in the flasks with the snapped necks had gone cloudy whereas the broth in the swan neck flasks remained clear
  • Thus Pasteur had shown that the swan necks prevented microorganisms in the air from entering the broth and that no organisms appeared spontaneously

The First Cells

  • The Oparin-Haldine hypothesis is that, to create the original first cells from non-living material, the following four stages occurred:
    1. Simple organic compounds needed to be synthesised from inorganic molecules (this was demonstrated by Stanley Miller and Harold Urey)
    2. Then assembled into polymers
    3. Some of these polymers (it is thought to be RNA) developed the ability to self-replicate (which enables inheritance)
    4. Formation of membranes (by lipids) that surrounded the polymers creating packages with internal chemistry different from the surroundings

1.2.1 The three key stages involved in life arising from non-living materials 1, downloadable IB Biology revision notes1.2.1 The three key stages involved in life arising from non-living materials 2, downloadable IB Biology revision notes1.2.1 The three key stages involved in life arising from non-living materials 3, downloadable IB Biology revision notes

The key stages involved in life arising from non-living materials

Miller-Urey experiment

  • Miller and Urey recreated the conditions thought to have existed on Earth prior to life, using a specific piece of apparatus
  • The apparatus allowed them to:
    • Boil water to produce steam reflecting the early primordial soup evaporating in the high temperatures that existed on Earth
    • Mix the steam with a mixture of gases (including methane, hydrogen and ammonia) that recreated the atmosphere
    • Add electrical discharges to the gases to stimulate lightning (one of the sources of energy available at the time)
    • Cool the mixture (representing the condensation of water in the atmosphere)
  • After a week Miller and Urey analysed the condensed mixture and found traces of simple organic molecules including amino acids

The apparatus used by Miller and Urey 1, downloadable IB Biology revision notesThe apparatus used by Miller and Urey 2, downloadable IB Biology revision notes

The apparatus used by Miller and Urey

Exam Tip

It is important to be able to explain how the experiments that Pasteur and Miller & Urey performed demonstrated the origin of cells.



  • 1. Cell Biology
    • 1.1 Cells: Theory
      • 1.1.1 Cell Theory
        • 1.1.2 Functions of Life
          • 1.1.3 Surface Area to Volume Ratio
            • 1.1.4 Cell Specialisation
              • 1.1.5 Stem Cells
                • 1.1.6 Skills: Cell Theory
                • 1.2 Cells: Origin & Ultrastructure
                  • 1.2.1 Origin of Cells
                    • 1.2.2 Endosymbiotic Theory
                      • 1.2.3 Prokaryotic Cell Structure
                        • 1.2.4 Eukaryotic Cell Structure
                          • 1.2.5 Exocrine Pancreatic & Palisade Mesophyll Cells
                            • 1.2.6 Comparison of Prokaryotic & Eukaryotic Cells
                              • 1.2.7 Microscopes
                                • 1.2.8 Skills: Drawing Cells
                                  • 1.2.9 Skills: Cell Origin & Ultrastructure
                                  • 1.3 Cells: Membrane Structure & Transport
                                    • 1.3.1 Phospholipid Bilayer Properties
                                      • 1.3.2 Membrane Proteins
                                        • 1.3.3 History of Fluid Mosaic Model
                                          • 1.3.4 Membrane Transport
                                            • 1.3.5 Active Transport & Bulk Transport
                                              • 1.3.6 Skills: Membrane Structure & Transport
                                                • 1.3.7 Skills: Estimation of Osmolarity
                                                • 1.4 Cells: Division
                                                  • 1.4.1 Cell Cycle
                                                    • 1.4.2 Phases of Mitosis
                                                      • 1.4.3 Cancer
                                                        • 1.4.4 Skills: Cell Division
                                                      • 2. Molecular Biology
                                                        • 2.1 Metabolism & Water
                                                          • 2.1.1 Molecules
                                                            • 2.1.2 Metabolism
                                                              • 2.1.3 Hydrogen Bonds
                                                                • 2.1.4 Water
                                                                • 2.2 Carbohydrates & Lipids
                                                                  • 2.2.1 Carbohydrates
                                                                    • 2.2.2 Fatty Acids
                                                                      • 2.2.3 Lipids
                                                                        • 2.2.4 Skills: Visualising Carbohydrates
                                                                          • 2.2.5 Skills: Calculating BMI
                                                                          • 2.3 Proteins
                                                                            • 2.3.1 Proteins
                                                                              • 2.3.2 Protein Structure & Function
                                                                                • 2.3.3 The Variety of Proteins
                                                                                  • 2.3.4 Skills: Molecules
                                                                                  • 2.4 Enzymes
                                                                                    • 2.4.1 Enzymes
                                                                                      • 2.4.2 Immobilised Enzymes
                                                                                        • 2.4.3 Skills: Enzyme Experiments
                                                                                        • 2.5 Nucleic Acids: Structure & DNA Replication
                                                                                          • 2.5.1 DNA & RNA Structure
                                                                                            • 2.5.2 DNA Replication
                                                                                              • 2.5.3 Skills: DNA Replication
                                                                                              • 2.6 Transcription & Translation
                                                                                                • 2.6.1 Transcription
                                                                                                  • 2.6.2 Translation
                                                                                                    • 2.6.3 Biotechnology
                                                                                                      • 2.6.4 Skills: DNA, RNA & Protein Synthesis
                                                                                                        • 2.6.5 Skills: Interpreting Sequences
                                                                                                        • 2.7 Cellular Respiration
                                                                                                          • 2.7.1 Cellular Respiration
                                                                                                            • 2.7.2 Anaerobic Respiration
                                                                                                              • 2.7.3 Aerobic Respiration
                                                                                                                • 2.7.4 Skills: Respiration
                                                                                                                • 2.8 Photosynthesis
                                                                                                                  • 2.8.1 Photosynthesis
                                                                                                                    • 2.8.2 Photosynthesis Continued
                                                                                                                      • 2.8.3 Skills: Photosynthesis
                                                                                                                        • 2.8.4 Skills: Separating Photosynthetic Pigments
                                                                                                                      • 3. Genetics
                                                                                                                        • 3.1 Genes & Chromosomes
                                                                                                                          • 3.1.1 Genes
                                                                                                                            • 3.1.2 Alleles
                                                                                                                              • 3.1.3 Mutation
                                                                                                                                • 3.1.4 Genome
                                                                                                                                  • 3.1.5 Prokaryotic Chromosomes
                                                                                                                                    • 3.1.6 Eukaryotic Chromosomes
                                                                                                                                      • 3.1.7 Chromosome Number
                                                                                                                                        • 3.1.8 Sex Determination
                                                                                                                                          • 3.1.9 Karyograms
                                                                                                                                            • 3.1.10 Skills: Using Databases
                                                                                                                                            • 3.2 Meiosis
                                                                                                                                              • 3.2.1 Meiosis
                                                                                                                                                • 3.2.2 Stages of Meiosis
                                                                                                                                                  • 3.2.3 Genetic Variation
                                                                                                                                                    • 3.2.4 Non-disjunction
                                                                                                                                                      • 3.2.5 Skills: Meiosis
                                                                                                                                                      • 3.3 Inheritance
                                                                                                                                                        • 3.3.1 Inheritance
                                                                                                                                                          • 3.3.2 Inheriting Alleles
                                                                                                                                                            • 3.3.3 Skills: Inheritance
                                                                                                                                                              • 3.3.4 Inheritance of Genetic Diseases
                                                                                                                                                                • 3.3.5 Mutations & Disease
                                                                                                                                                                • 3.4 Genetic Modification & Biotechnology
                                                                                                                                                                  • 3.4.1 Electrophoresis & PCR
                                                                                                                                                                    • 3.4.2 DNA Profiling
                                                                                                                                                                      • 3.4.3 Genetic Modification
                                                                                                                                                                        • 3.4.4 Cloning
                                                                                                                                                                          • 3.4.5 Skills: Genetic Modification & Biotechnology
                                                                                                                                                                        • 4. Ecology
                                                                                                                                                                          • 4.1 Species, Communities, Ecosystems & Energy Flow
                                                                                                                                                                            • 4.1.1 Species & Population
                                                                                                                                                                              • 4.1.2 Methods of Nutrition
                                                                                                                                                                                • 4.1.3 Community
                                                                                                                                                                                  • 4.1.4 Nutrient Cycling
                                                                                                                                                                                    • 4.1.5 Energy Flow
                                                                                                                                                                                      • 4.1.6 Energy Losses
                                                                                                                                                                                        • 4.1.7 Skills: Species, Communities, Ecosystems & Energy Flow
                                                                                                                                                                                          • 4.1.8 Skills: Chi-squared test & Statistical Significance
                                                                                                                                                                                            • 4.1.9 Skills: Pyramids of Energy
                                                                                                                                                                                            • 4.2 Carbon Cycling & Climate Change
                                                                                                                                                                                              • 4.2.1 Carbon Cycle: Carbon Dioxide
                                                                                                                                                                                                • 4.2.2 Carbon Cycle: Carbon Dioxide in the Atmosphere
                                                                                                                                                                                                  • 4.2.3 Carbon Cycle: Methane
                                                                                                                                                                                                    • 4.2.4 Carbon Cycle: Organic Matter
                                                                                                                                                                                                      • 4.2.5 Climate Change: Greenhouse Effect
                                                                                                                                                                                                        • 4.2.6 Climate Change: Impact
                                                                                                                                                                                                          • 4.2.7 Climate Change: Causes
                                                                                                                                                                                                            • 4.2.8 Skills: Carbon Cycling & Climate Change
                                                                                                                                                                                                          • 5. Evolution and biodiversity
                                                                                                                                                                                                            • 5.1 Evolution & Natural Selection
                                                                                                                                                                                                              • 5.1.1 Evolution
                                                                                                                                                                                                                • 5.1.2 Evolution: Evidence
                                                                                                                                                                                                                  • 5.1.3 Variation
                                                                                                                                                                                                                    • 5.1.4 Natural Selection
                                                                                                                                                                                                                      • 5.1.5 Natural Selection Examples
                                                                                                                                                                                                                      • 5.2 Classification & Cladistics
                                                                                                                                                                                                                        • 5.2.1 Classification System
                                                                                                                                                                                                                          • 5.2.2 Classifying Organisms
                                                                                                                                                                                                                            • 5.2.3 Plant Phyla Features
                                                                                                                                                                                                                              • 5.2.4 Animal Phyla Features
                                                                                                                                                                                                                                • 5.2.5 Cladistics
                                                                                                                                                                                                                                  • 5.2.6 Reclassification
                                                                                                                                                                                                                                    • 5.2.7 Skills: Classification & Cladistics
                                                                                                                                                                                                                                  • 6. Human Physiology
                                                                                                                                                                                                                                    • 6.1 Digestion & Absorption
                                                                                                                                                                                                                                      • 6.1.1 Digestion
                                                                                                                                                                                                                                        • 6.1.2 Villi & Absorption
                                                                                                                                                                                                                                          • 6.1.3 Absorption
                                                                                                                                                                                                                                            • 6.1.4 Skills: Digestion & Absorption
                                                                                                                                                                                                                                            • 6.2 The Blood System
                                                                                                                                                                                                                                              • 6.2.1 The Blood System: History
                                                                                                                                                                                                                                                • 6.2.2 The Blood System: Vessels
                                                                                                                                                                                                                                                  • 6.2.3 The Blood System: Double Circulation
                                                                                                                                                                                                                                                    • 6.2.4 The Blood System: Cardiac Cycle
                                                                                                                                                                                                                                                      • 6.2.5 The Heart Rate
                                                                                                                                                                                                                                                        • 6.2.6 Skills: The Blood System
                                                                                                                                                                                                                                                        • 6.3 Defence Against Infectious Disease
                                                                                                                                                                                                                                                          • 6.3.1 Skin
                                                                                                                                                                                                                                                            • 6.3.2 Blood Clotting
                                                                                                                                                                                                                                                              • 6.3.3 White Blood Cells
                                                                                                                                                                                                                                                                • 6.3.4 Antibiotics
                                                                                                                                                                                                                                                                  • 6.3.5 Antibiotic Resistance
                                                                                                                                                                                                                                                                  • 6.4 Gas Exchange
                                                                                                                                                                                                                                                                    • 6.4.1 Ventilation: Function & Structures
                                                                                                                                                                                                                                                                      • 6.4.2 Ventilation: Mechanism
                                                                                                                                                                                                                                                                        • 6.4.3 Lung Diseases
                                                                                                                                                                                                                                                                          • 6.4.4 Skills: Monitoring Ventilation
                                                                                                                                                                                                                                                                          • 6.5 Neurones & Synapses
                                                                                                                                                                                                                                                                            • 6.5.1 Neurones: Function & Structure
                                                                                                                                                                                                                                                                              • 6.5.2 Nerve Impulses
                                                                                                                                                                                                                                                                                • 6.5.3 Synapses
                                                                                                                                                                                                                                                                                  • 6.5.4 Skill: Neurones & Synapses
                                                                                                                                                                                                                                                                                  • 6.6 Hormones, Homeostasis & Reproduction
                                                                                                                                                                                                                                                                                    • 6.6.1 Hormones
                                                                                                                                                                                                                                                                                      • 6.6.2 Hormones Continued
                                                                                                                                                                                                                                                                                        • 6.6.3 Reproduction: Background
                                                                                                                                                                                                                                                                                          • 6.6.4 Reproduction: Sex Determination in Males
                                                                                                                                                                                                                                                                                            • 6.6.5 Reproduction: Sex Determination in Females
                                                                                                                                                                                                                                                                                              • 6.6.6 Skills: Reproduction Diagrams

                                                                                                                                                                                                                                                                                            Author: Catherine

                                                                                                                                                                                                                                                                                            Cate has over 20 years’ experience teaching Biology to IGCSE, IB and A-level students in seven different countries across Asia, Europe, North America and the Middle East. This has given her a fine appreciation of different cultures, places and teaching methods. Cate has a keen interest in producing Biology revision resources that will help students engage with the subject.


                                                                                                                                                                                                                                                                                            Save My Exams Logo
                                                                                                                                                                                                                                                                                            Resources
                                                                                                                                                                                                                                                                                            Home Join Support

                                                                                                                                                                                                                                                                                            Members
                                                                                                                                                                                                                                                                                            Members Home Account Logout

                                                                                                                                                                                                                                                                                            Company
                                                                                                                                                                                                                                                                                            About Us Contact Us Jobs Terms Privacy Facebook Twitter

                                                                                                                                                                                                                                                                                            Quick Links
                                                                                                                                                                                                                                                                                            GCSE Revision Notes IGCSE Revision Notes A Level Revision Notes Biology Chemistry Physics Maths 2022 Advance Information

                                                                                                                                                                                                                                                                                             
                                                                                                                                                                                                                                                                                            © IB Documents (2) Team & u/aimlesskr
                                                                                                                                                                                                                                                                                            IBO was not involved in the production of, and does not endorse, the resources created by Save My Exams.