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DP IB Biology: HL

Revision Notes

Home / IB / Biology: HL / DP / Revision Notes / 7. Nucleic Acids (HL Only) / 7.2 Transcription & Gene Expression / 7.2.4 Post-transcriptional Modification


7.2.4 Post-transcriptional Modification


Modification of RNA

  • In all kingdoms of life, gene expression can be regulated after an mRNA transcript has been produced
  • Post-transcriptional modification of mRNA
    • Helps prevent degradation
      • mRNA is single stranded and therefore, inherently unstable
    • Increases the efficiency of protein synthesis
    • In eukaryotes, expands the complexity of the proteome
  • Prokaryotic mRNA does not require any significant post-transcriptional modification as translation can occur immediately which prevents degradation of the mRNA
  • In eukaryotes, transcription and translation occur in separate parts of the cell, allowing for significant post-transcriptional modification to occur
  • In eukaryotes, the immediate product of an mRNA transcript is called pre-mRNA which needs to be modified to form mature mRNA
  • Three post-transcriptional events must occur
    1. A methylated cap is added to the 5' end to protect against degradation by exonucleases
    2. A poly-A tail (long chain of adenine nucleotides) is added to the 3' end for further protection and to help the transcript exit the nucleus
    3. Non-coding sequences are removed through mRNA splicing

mRNA Splicing

  • Eukaryotic genes contain both coding and non-coding sequences of DNA
    • Coding sequences are called exons
    • Non-coding sequences are called introns
  • During transcription the whole gene is transcribed including all introns and exons
    • Introns are not translated as they do not code for amino acids and need to be removed
  • Before the pre-mRNA exits the nucleus, splicing occurs, during which
    • Introns (non-coding sections) are removed
    • Exons (coding sections) are joined together
    • The resulting mature mRNA molecule contains only exons and exits the nucleus before joining a ribosome for translation

Splicing of pre-mRNA 1, downloadable AS Level & A Level Biology revision notes Splicing of pre-mRNA 2, downloadable AS Level & A Level Biology revision notes

The RNA molecule (known as pre-mRNA) produced from the transcription of a gene contains introns that must be removed (to form mature mRNA) before translation can occur

Alternative splicing

  • The exons (coding regions) of genes can be spliced in many different ways to produce different mature mRNA molecules through alternative splicing
  • A particular exon may or may not be incorporated into the final mature mRNA
  • Polypeptides translated from alternatively spliced mRNAs may differ in their amino acid sequence, structure and function
  • This means that a single eukaryotic gene can code for multiple proteins
  • This is part of the reason why the proteome is much bigger than the genome

Alternative Splicing, downloadable AS & A Level Biology revision notes

Image showing the alternative splicing of a gene to produce two different proteins

Exam Tip

It is important you learn the terms pre-mRNA and mRNA, their location and whether they include introns as well as exons. A handy way to distinguish between introns and exons is to remember that EXons are EXpressed.


  • 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
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          Phil Chatterton

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          Author: Phil

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          Phil graduated in Biochemistry from Birmingham University and spent seventeen years in the drinks and chemicals industries. He holds an MBA from Manchester Business School. More recently, Phil has taught in secondary schools, examined GCSE Biology and has also co-directed a tuition agency. He is a passionate believer in promoting numeracy in his teaching and loves to create innovative resources.


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