Classical, alternative, and lectin complement pathways and the deficiency disorders tied to each component tested on USMLE Step 1.
About this set
29 basic cards for USMLE Step 1 Immunology. Set 4 of 10 in USMLE Immunology. It opens with "Which complement protein is the first to be activated in the classical pathway?" and "What directly triggers activation of the classical complement pathway?". Study it alongside the other USMLE Step 1 sets below.
29 cards · basic cards · AI-written, checked twice. Edit anything.
- Which complement protein is the first to be activated in the classical pathway?
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C1q- What directly triggers activation of the classical complement pathway?
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Antigen-antibody (immune) complexes binding C1q- Which antibody isotype is the most efficient activator of the classical complement pathway?
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IgM- IgM is a more efficient activator of the classical complement pathway than IgG because IgM's ____ structure can bind multiple C1q heads at once.
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pentameric- What is the C3 convertase of the classical pathway?
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C4b2a- What triggers activation of the lectin complement pathway?
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Mannose-binding lectin (MBL) binding mannose residues on a pathogen surface- Which enzymes does mannose-binding lectin activate to drive the lectin pathway?
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MASPs (MBL-associated serine proteases)- What triggers activation of the alternative complement pathway?
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Spontaneous hydrolysis of C3 on a microbial surface, without antibody- What is the C3 convertase of the alternative pathway?
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C3bBb- Which protein stabilizes the alternative pathway's C3 convertase?
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Properdin (factor P)- Which protein binds C3b and is then cleaved by factor D in the alternative pathway?
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Factor B- What is the C5 convertase formed by the classical and lectin pathways?
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C4b2a3b- What is the C5 convertase formed by the alternative pathway?
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C3bBb3b- Which complement proteins make up the membrane attack complex?
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C5b-9- What is the main function of the membrane attack complex?
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It lyses the pathogen cell membrane, especially gram-negative bacteria like Neisseria
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