51: Recombinases and Topoisomerase I.                                                  

52: Recombination Mechanism.                                                         

53: Holliday Junction.                                                             

54: Recombination.                                                            

55: DNA Replication of Both Strands Proceeds Rapidly from Specific Start Sites

56: Telomere Formation.                                                             

57: Proposed Model for Telomeres.                                                      

58:Eukaryotic Cell Cycle.                                                             

59: Coordination between the Leading and the Lagging Strands.                    

60: Replication Fork.                                                             

61: Structure of the Sliding Clamp.                                                      

62: Proposed Architecture of DNA Polymerase III Holoenzyme.                    

63: DNA Ligase Mechanism.                                                           

64: DNA Ligase Reaction.                                                            

The Immune System

65: Diversity Is Generated by Gene Rearrangements                                    

66: Class Switching.                                                             

67: B-Cell Activation.                                                             

68: B-Cell Receptor.                                                             

69: V( D ) J Recombination.                                                           

70: Light-Chain Expression.                                                           

71: VJ Recombination.                                                             

72: The Kappa Light-Chain Locus.                                                       

73: Antibodies Bind Specific Molecules Through Their Hypervariable Loops    

74: Antibody - Protein Interactions.                                                      

75: Antibodies Against Lysozyme.                                                       

76: Binding of a Small Antigen.                                                         

77: Variable Domains.                                                             

78: The Immunoglobulin Fold Consists of a Beta-Sandwich Framework with Hypervariable Loops         

79: Immunoglobulin Fold.                                                            

80: Antibodies Possess Distinct Antigen-Binding and Effector Units               

81: Variable and Constant Regions.                                                      

82: Immunoglobulin Sequence Diversity.                                                 

83: Properties of immunoglobulin classes                                                  

84: Classes of Immuno-Globulin.                                                        

85: Segmental Flexibility.                                                             

86: Antigen Cross-Linking.                                                            

87: Immunoglobulin G Cleavage.                                                        

88: Immunoglobulin G Structure.                                                        

89: Just as Medieval defenders used their weapons and the castle walls to defend their city, the immune system constantly battles against foreign invaders such as viruses, bacteria, and parasites to defend the organism.             

90: Immunoglobulin Production.                                                        

91: The Immune System                                                                       

92: Problems                                                                                         

93: Summary                                                                                         

94: Immune Responses Against Self-Antigens Are Suppressed               

95: Consequences of Autoimmunity.                                                   

96: T-Cell Selection.                                                                             

97: Major-Histocompatibility-Complex Proteins Present Peptide Antigens on Cell Surfaces for Recognition by T-Cell Receptors                                                                                               

98: HIV Receptor.                                                                                

99: Human Immunodeficiency Virus.                                                  

100: Polymorphism in Class I MHC Protein.