• 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: HL

Revision Notes

Home / IB / Biology: HL / DP / Revision Notes / 8. Metabolism, Cell Respiration & Photosynthesis (HL Only) / 8.3 Photosynthesis / 8.3.2 Photophosphorylation


8.3.2 Photophosphorylation


The Electron Transport Chain in Photosynthesis

  • Photophosphorylation is the term for the overall process of using light energy and the electron transport chain to generate ATP from ADP
  • During photophosphorylation excited electrons (from Photosystem II) are passed down a series of electron carriers that form the electron transport chain
  • The electron transport chain occurs on the thylakoid membranes within the chloroplast
  • Thylakoid membranes contain the following structures:
    • Photosystem II
    • ATP synthase
    • A series of electron carriers
    • Photosystem I
  • The reduced plastoquinone (an electron acceptor forming part of the electron transport chain)  carries a pair of excited electrons from Photosystem II
  • Plastoquinone carries the electrons to the start of a chain of electron carriers
  • The electron carriers undergo a series of redox reactions as electrons are gained and lost from each carrier
  • Excited electrons gradually release their energy as they pass through the electron carriers which is used to generate a proton gradient
  • The excitation of the electrons falls and they are eventually picked up by the reaction centre in Photosystem I
  • Finally the pair of electrons are used to reduce NADP (along with protons from the photolysis of water) which is then passed into the light-independent reaction
  • The pathway of electrons is linear, photophosphorylation is referred to as non-cyclic photophosphorylation
  • ATP and reduced NADP are the main products of photophosphorylation and are immediately passed to the light-independent reaction
Non-cyclic photophosphorylation (1)_1Non-cyclic photophosphorylation (2)_1Non-cyclic photophosphorylation (3)
Non cyclic phosphorylation involving the electron transport chain and the production of ATP and reduced NADP

Exam Tip

Remember a redox reaction is one where reduction reactions (gain of electrons or hydrogen, loss of oxygen) and oxidation reactions (loss of electrons or hydrogen, gain of oxygen) happen alternately. This happens along the series of electron carriers in the thylakoid membrane as part of the electron transport chain.

Forming the Proton Gradient

  • Electrons are passed from carrier to carrier in the electron transport chain
  • As they do so they release energy which is used to pump protons from the stroma across the thylakoid membrane and into the intermembrane space (also known as the the thylakoid lumen)
  • The protons move via a proton pump
  • A high concentration of protons builds inside the intermembrane space creating a concentration gradient
  • Photolysis of water contributes to the proton gradient

Chemiosmosis in Photosynthesis

  • The proton gradient within the intermembrane space of the thylakoid powers the synthesis of ATP
    • The protons travel down their concentration gradient through the membrane protein ATP synthase
    • Energy is released by the movement of protons and is used to make ATP from the phosphorylation of ADP
  • This process is called chemiosmosis
  • The ATP produced is used in the light-independent reaction

photophosphorylation-and-chemiosmosis

Photophosphorylation and chemiosmosis

Reduction of NADP

  • Photosystem I is involved in the reduction of NADP which is a key molecule used in the light-independent reaction
    • Chlorophyll molecules in the reaction centre absorb photons of light energy
    • Electrons within the reaction centre are photoactivated to a higher energy level
    • They are passed to a protein on the outside of the thylakoid membrane called ferredoxin and reduce it
    • The reduced ferredoxin, along with protons that have passed through ATP synthase during chemiosmosis, are used to reduce NADP to NADPH (reduced NADP)
      • NADP + 2H⁺ + 2e⁻ → NADPH
    • The ferredoxin is now oxidised and free to be reused in this reaction again
    • Reduced NADP now carries a pair of electrons and can be passed into the light-independent reactions of photosynthesis

reduction-nadp-in-photosynthesis

Reduction of NADP in Photosystem I



  • 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
                                                                                                                                                                                                                                                                                            • 7. Nucleic Acids (HL Only)
                                                                                                                                                                                                                                                                                              • 7.1 DNA Structure & Replication
                                                                                                                                                                                                                                                                                                • 7.1.1 DNA Structure
                                                                                                                                                                                                                                                                                                  • 7.1.2 Mechanism of DNA Replication
                                                                                                                                                                                                                                                                                                    • 7.1.3 Non-coding DNA
                                                                                                                                                                                                                                                                                                      • 7.1.4 DNA Sequencing
                                                                                                                                                                                                                                                                                                        • 7.1.5 Skills: The Hershey & Chase Experiment
                                                                                                                                                                                                                                                                                                          • 7.1.6 Skills: Nucleosomes & Molecular Visualisation Software
                                                                                                                                                                                                                                                                                                          • 7.2 Transcription & Gene Expression
                                                                                                                                                                                                                                                                                                            • 7.2.1 Regulation of Gene Expression by Proteins
                                                                                                                                                                                                                                                                                                              • 7.2.2 Environment & Gene Expression
                                                                                                                                                                                                                                                                                                                • 7.2.3 Transcription
                                                                                                                                                                                                                                                                                                                  • 7.2.4 Post-transcriptional Modification
                                                                                                                                                                                                                                                                                                                    • 7.2.5 Skills: Analysing DNA Methylation Patterns
                                                                                                                                                                                                                                                                                                                    • 7.3 Translation
                                                                                                                                                                                                                                                                                                                      • 7.3.1 Translation
                                                                                                                                                                                                                                                                                                                        • 7.3.2 Ribosomes
                                                                                                                                                                                                                                                                                                                          • 7.3.3 Translation in Prokaryotes
                                                                                                                                                                                                                                                                                                                            • 7.3.4 Bioinformatics
                                                                                                                                                                                                                                                                                                                              • 7.3.5 Levels of Protein Structure
                                                                                                                                                                                                                                                                                                                                • 7.3.6 Skills: Polysomes & Ribosomes
                                                                                                                                                                                                                                                                                                                              • 8. Metabolism, Cell Respiration & Photosynthesis (HL Only)
                                                                                                                                                                                                                                                                                                                                • 8.1 Metabolism
                                                                                                                                                                                                                                                                                                                                  • 8.1.1 Metabolic Pathways
                                                                                                                                                                                                                                                                                                                                    • 8.1.2 Inhibition
                                                                                                                                                                                                                                                                                                                                      • 8.1.3 Bioinformatics & Metabolism
                                                                                                                                                                                                                                                                                                                                        • 8.1.4 Skills: Rates of Reaction & Types of Inhibition
                                                                                                                                                                                                                                                                                                                                        • 8.2 Cell Respiration
                                                                                                                                                                                                                                                                                                                                          • 8.2.1 Oxidation, Reduction & Phosphorylation
                                                                                                                                                                                                                                                                                                                                            • 8.2.2 Overview of the Stages of Respiration
                                                                                                                                                                                                                                                                                                                                              • 8.2.3 Glycolysis
                                                                                                                                                                                                                                                                                                                                                • 8.2.4 The Link Reaction & The Krebs Cycle
                                                                                                                                                                                                                                                                                                                                                  • 8.2.5 Oxidative Phosphorylation
                                                                                                                                                                                                                                                                                                                                                    • 8.2.6 Mitochondria
                                                                                                                                                                                                                                                                                                                                                      • 8.2.7 Skills: Cell Respiration
                                                                                                                                                                                                                                                                                                                                                      • 8.3 Photosynthesis
                                                                                                                                                                                                                                                                                                                                                        • 8.3.1 Light-dependent Reactions
                                                                                                                                                                                                                                                                                                                                                          • 8.3.2 Photophosphorylation
                                                                                                                                                                                                                                                                                                                                                            • 8.3.3 Light-independent Reactions
                                                                                                                                                                                                                                                                                                                                                              • 8.3.4 Investigating Carbon Fixation in Photosynthesis
                                                                                                                                                                                                                                                                                                                                                                • 8.3.5 Chloroplast
                                                                                                                                                                                                                                                                                                                                                                  • 8.3.6 Skills: Photosynthesis
                                                                                                                                                                                                                                                                                                                                                                • 9. Plant Biology (HL Only)
                                                                                                                                                                                                                                                                                                                                                                  • 9.1 Transport in the Xylem of Plants
                                                                                                                                                                                                                                                                                                                                                                    • 9.1.1 Transpiration in Plants
                                                                                                                                                                                                                                                                                                                                                                      • 9.1.2 The Transpiration Stream
                                                                                                                                                                                                                                                                                                                                                                        • 9.1.3 The Roots & Water Transport
                                                                                                                                                                                                                                                                                                                                                                          • 9.1.4 Adaptations of Xerophytes
                                                                                                                                                                                                                                                                                                                                                                            • 9.1.5 Skills: Drawing Xylem Vessels
                                                                                                                                                                                                                                                                                                                                                                              • 9.1.6 Skills: Experiments Investigating the Rate of Transpiration
                                                                                                                                                                                                                                                                                                                                                                              • 9.2 Transport in the Phloem of Plants
                                                                                                                                                                                                                                                                                                                                                                                • 9.2.1 Translocation in Plants
                                                                                                                                                                                                                                                                                                                                                                                  • 9.2.2 Sucrose Loading
                                                                                                                                                                                                                                                                                                                                                                                    • 9.2.3 Hydrostatic Pressure Gradients
                                                                                                                                                                                                                                                                                                                                                                                      • 9.2.4 Skills: Identifying Xylem & Phloem
                                                                                                                                                                                                                                                                                                                                                                                        • 9.2.5 Skills: Measuring Phloem Transport Rates
                                                                                                                                                                                                                                                                                                                                                                                        • 9.3 Growth in Plants
                                                                                                                                                                                                                                                                                                                                                                                          • 9.3.1 Plant Growth
                                                                                                                                                                                                                                                                                                                                                                                            • 9.3.2 Plant Hormones
                                                                                                                                                                                                                                                                                                                                                                                              • 9.3.3 Micropropagation
                                                                                                                                                                                                                                                                                                                                                                                              • 9.4 Reproduction in Plants
                                                                                                                                                                                                                                                                                                                                                                                                • 9.4.1 Flowering
                                                                                                                                                                                                                                                                                                                                                                                                  • 9.4.2 Plant Reproduction
                                                                                                                                                                                                                                                                                                                                                                                                    • 9.4.3 Skills: Drawing Plant Structures
                                                                                                                                                                                                                                                                                                                                                                                                      • 9.4.4 Skills: Investigating Factors Affecting Germination
                                                                                                                                                                                                                                                                                                                                                                                                    • 10. Genetics & Evolution (HL Only)
                                                                                                                                                                                                                                                                                                                                                                                                      • 10.1 Meiosis
                                                                                                                                                                                                                                                                                                                                                                                                        • 10.1.1 The Process of Meiosis
                                                                                                                                                                                                                                                                                                                                                                                                          • 10.1.2 Crossing Over
                                                                                                                                                                                                                                                                                                                                                                                                            • 10.1.3 Meiosis I
                                                                                                                                                                                                                                                                                                                                                                                                              • 10.1.4 Meiosis II
                                                                                                                                                                                                                                                                                                                                                                                                                • 10.1.5 Skills: Drawing Chiasmata
                                                                                                                                                                                                                                                                                                                                                                                                                • 10.2 Inheritance
                                                                                                                                                                                                                                                                                                                                                                                                                  • 10.2.1 Unlinked Genes
                                                                                                                                                                                                                                                                                                                                                                                                                    • 10.2.2 Skills: Analysing Dihybrid Crosses
                                                                                                                                                                                                                                                                                                                                                                                                                      • 10.2.3 Gene Linkage
                                                                                                                                                                                                                                                                                                                                                                                                                        • 10.2.4 Skills: Identifying Recombinants
                                                                                                                                                                                                                                                                                                                                                                                                                          • 10.2.5 Skills: Chi-squared Test
                                                                                                                                                                                                                                                                                                                                                                                                                            • 10.2.6 Variation
                                                                                                                                                                                                                                                                                                                                                                                                                            • 10.3 Gene Pools & Speciation
                                                                                                                                                                                                                                                                                                                                                                                                                              • 10.3.1 Gene Pools
                                                                                                                                                                                                                                                                                                                                                                                                                                • 10.3.2 Evolution
                                                                                                                                                                                                                                                                                                                                                                                                                                  • 10.3.3 Speciation
                                                                                                                                                                                                                                                                                                                                                                                                                                    • 10.3.4 Polyploidy & Speciation
                                                                                                                                                                                                                                                                                                                                                                                                                                      • 10.3.5 Skills: Comparing Allele Frequencies Between Populations
                                                                                                                                                                                                                                                                                                                                                                                                                                    • 11. Animal Physiology (HL Only)
                                                                                                                                                                                                                                                                                                                                                                                                                                      • 11.1 Antibody Production & Vaccination
                                                                                                                                                                                                                                                                                                                                                                                                                                        • 11.1.1 Antigens
                                                                                                                                                                                                                                                                                                                                                                                                                                          • 11.1.2 Specific Immune Response
                                                                                                                                                                                                                                                                                                                                                                                                                                            • 11.1.3 Antibodies, Vaccines & Immunity
                                                                                                                                                                                                                                                                                                                                                                                                                                              • 11.1.4 Smallpox Vaccine & Eradication
                                                                                                                                                                                                                                                                                                                                                                                                                                                • 11.1.5 Zoonosis
                                                                                                                                                                                                                                                                                                                                                                                                                                                  • 11.1.6 Histamines
                                                                                                                                                                                                                                                                                                                                                                                                                                                    • 11.1.7 Monoclonal Antibodies
                                                                                                                                                                                                                                                                                                                                                                                                                                                      • 11.1.8 Skills: Analysing Epidemiological Data
                                                                                                                                                                                                                                                                                                                                                                                                                                                      • 11.2 Movement
                                                                                                                                                                                                                                                                                                                                                                                                                                                        • 11.2.1 Requirements for Movement
                                                                                                                                                                                                                                                                                                                                                                                                                                                          • 11.2.2 Skeletal Muscle
                                                                                                                                                                                                                                                                                                                                                                                                                                                            • 11.2.3 Mechanism of Muscle Contraction
                                                                                                                                                                                                                                                                                                                                                                                                                                                              • 11.2.4 Skills: The Human Elbow & Sarcomeres
                                                                                                                                                                                                                                                                                                                                                                                                                                                                • 11.2.5 Skills: Analysing Muscle Contractions in Electron Micrographs
                                                                                                                                                                                                                                                                                                                                                                                                                                                                • 11.3 The Kidney & Osmoregulation
                                                                                                                                                                                                                                                                                                                                                                                                                                                                  • 11.3.1 Osmoregulation in Organisms
                                                                                                                                                                                                                                                                                                                                                                                                                                                                    • 11.3.2 Kidney: Structure & Function
                                                                                                                                                                                                                                                                                                                                                                                                                                                                      • 11.3.3 Conserving Water
                                                                                                                                                                                                                                                                                                                                                                                                                                                                        • 11.3.4 The Role of ADH
                                                                                                                                                                                                                                                                                                                                                                                                                                                                          • 11.3.5 Types of Nitrogenous Waste
                                                                                                                                                                                                                                                                                                                                                                                                                                                                            • 11.3.6 Kidney Failure & Urinalysis
                                                                                                                                                                                                                                                                                                                                                                                                                                                                              • 11.3.7 Skills: Drawing & Annotating the Kidney
                                                                                                                                                                                                                                                                                                                                                                                                                                                                              • 11.4 Sexual Reproduction
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                • 11.4.1 Oogenesis & Spermatogenesis
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  • 11.4.2 Fertilisation
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    • 11.4.3 Pregnancy
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      • 11.4.4 Hormones in Pregnancy
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        • 11.4.5 The Placenta
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          • 11.4.6 Oestrogen Pollution
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            • 11.4.7 Skills: Annotating Sexual Reproduction Diagrams

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          Author: Cara

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          Cara graduated from the University of Exeter in 2005 with a degree in Biological Sciences. She has fifteen years of experience teaching the Sciences at KS3 to KS5, and Psychology at A-Level. Cara has taught in a range of secondary schools across the South West of England before joining the team at SME. Cara is passionate about Biology and creating resources that bring the subject alive and deepen students' understanding


                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          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.