Radiation Biology

  1. Molecular Radiobiology
    1. DNA as the Critical Target
      1. DNA Structure and Organization
        1. Double Helix Structure
          1. Base Pairing
            1. Sugar-Phosphate Backbone
              1. Chromatin Organization
              2. DNA as a Radiation Target
                1. Size and Accessibility
                  1. Critical Nature for Cell Survival
                    1. Repair vs. Misrepair Consequences
                  2. Types of Radiation-Induced DNA Damage
                    1. Single-Strand Breaks
                      1. Direct and Indirect Formation
                        1. Frequency and Distribution
                          1. Biological Significance
                          2. Double-Strand Breaks
                            1. Formation Mechanisms
                              1. Complexity and Clustering
                                1. Biological Consequences
                                2. Base Damage
                                  1. Oxidative Base Modifications
                                    1. Base Loss (Abasic Sites)
                                      1. Specific Base Lesions
                                      2. Sugar Damage
                                        1. Deoxyribose Modifications
                                          1. Strand Break Formation
                                          2. Clustered DNA Damage
                                            1. Definition and Characteristics
                                              1. Repair Complexity
                                                1. Biological Significance
                                              2. DNA Repair Mechanisms
                                                1. Base Excision Repair
                                                  1. Recognition of Base Damage
                                                    1. Glycosylase Action
                                                      1. AP Endonuclease Activity
                                                        1. Polymerase and Ligase Steps
                                                          1. Short-Patch vs. Long-Patch Repair
                                                          2. Nucleotide Excision Repair
                                                            1. Global Genome Repair
                                                              1. Transcription-Coupled Repair
                                                                1. Recognition and Incision
                                                                  1. Repair Synthesis
                                                                  2. Single-Strand Break Repair
                                                                    1. PARP Activation
                                                                      1. End Processing
                                                                        1. Gap Filling
                                                                        2. Double-Strand Break Repair
                                                                          1. Homologous Recombination
                                                                            1. Mechanism and Steps
                                                                              1. RAD51 and Recombinase Activity
                                                                                1. Fidelity of Repair
                                                                                2. Non-Homologous End Joining
                                                                                  1. Classical NHEJ
                                                                                    1. Alternative NHEJ
                                                                                      1. Error-Prone Nature
                                                                                      2. Microhomology-Mediated Break-Induced Replication
                                                                                      3. Mismatch Repair
                                                                                        1. Recognition of Mismatches
                                                                                          1. Excision and Resynthesis
                                                                                          2. DNA Damage Checkpoints
                                                                                            1. ATM and ATR Kinases
                                                                                              1. p53 Pathway
                                                                                                1. Cell Cycle Arrest
                                                                                                2. Factors Affecting Repair Efficiency
                                                                                                  1. Cell Type Variations
                                                                                                    1. Genetic Polymorphisms
                                                                                                      1. Environmental Factors
                                                                                                    2. Damage to Other Cellular Components
                                                                                                      1. Lipid Peroxidation
                                                                                                        1. Initiation by Free Radicals
                                                                                                          1. Propagation Reactions
                                                                                                            1. Membrane Damage
                                                                                                              1. Cellular Consequences
                                                                                                              2. Protein Damage
                                                                                                                1. Amino Acid Modifications
                                                                                                                  1. Cross-Linking
                                                                                                                    1. Enzyme Inactivation
                                                                                                                      1. Structural Alterations
                                                                                                                      2. Carbohydrate Damage
                                                                                                                        1. Mitochondrial DNA Damage
                                                                                                                          1. Unique Vulnerabilities
                                                                                                                            1. Repair Limitations
                                                                                                                              1. Functional Consequences

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                                                                                                                          4. Cellular Radiobiology