Complement 1 Classical Pathway

The video tutorial explains the complement system, a crucial part of the immune system, focusing on the classical pathway. It details the structure and function of antibodies, the activation of the complement system through antibodies, and the formation of C3 and C5 convertases. The tutorial also covers the role of C4 and C2 in the process and the formation of the membrane attack complex, which ultimately lyses pathogens.

Which of the following is NOT a pathway of complement system activation?

• Classical pathway

• Cytokine pathway

• Alternative pathway

• Lectin pathway

What is the primary role of the complement system in the immune response?

• To destroy red blood cells

• To produce antibodies

• To enhance the function of antibodies

• To create new immune cells

What is the first component that binds to the antibody in the classical pathway?

• C4

• C1Q

• C2

• C3

Which antibodies are primarily involved in activating the complement system?

• IgM and IgG

• IgA and IgD

• IgA and IgE

• IgD and IgE

What is the role of C3 convertase in the complement system?

• To bind to antibodies

• To split C3 into C3A and C3B

• To activate C1Q

• To form the membrane attack complex

What is the significance of the thioester bond in C4?

• It prevents C4 from binding to the antigen

• It is involved in antibody production

• It allows C4 to bind to the antigen

• It stabilizes the protein structure

What is the function of C5 convertase in the complement system?

• To activate C1Q

• To split C5 into C5A and C5B

• To form C3 convertase

• To bind to antibodies

What does the 'A' in C5A stand for in the context of the complement system?

• Antigen

• Attached

• Away

• Active

What is the primary function of the membrane attack complex?

• To lyse pathogens

• To produce antibodies

• To bind to antibodies

• To activate C1Q

What is one protective mechanism the body uses to prevent complement activation on its own cells?

• Inactivation of C1Q

• Stabilization of the thioester bond

• Activation of C5 convertase

• Hydrolysis of the thioester bond