Antibody Structure and Function Quiz

The primary structural difference is that the B-cell receptor has a hydrophobic membrane-anchoring sequence at the C-terminus, while the antibody has a hydrophilic sequence that allows for secretion.

Antibodies bind to a wide variety of antigens and interact with a limited number of effector molecules and cells.

Antibody molecules are roughly Y-shaped, consisting of three equal-sized portions connected by a flexible tether.

<p>The variable regions of antibodies are called V regions, and they are involved in binding to antigens.</p> Signup and view all the answers

<p>The C region, which is less variable than the V regions, interacts with effector cells and molecules.</p> Signup and view all the answers

<p>All antibodies are classified under the generic term immunoglobulin, as they are constructed from paired heavy and light polypeptide chains.</p> Signup and view all the answers

<p>Antibodies are soluble and secreted in large quantities, making them easily obtainable and more accessible for study.</p> Signup and view all the answers

<p>The structure of antibodies was determined using X-ray crystallography.</p> Signup and view all the answers

<p>IgG antibodies consist of heavy chains and light chains.</p> Signup and view all the answers

<p>An IgG molecule has two identical antigen-binding sites.</p> Signup and view all the answers

<p>Disulfide bonds link heavy chains to each other and light chains to heavy chains, stabilizing the structure.</p> Signup and view all the answers

<p>The two types of light chains are lambda (λ) and kappa (κ).</p> Signup and view all the answers

<p>The class of an antibody is determined by the structure of its heavy chain.</p> Signup and view all the answers

<p>The molecular weight of IgG antibodies is approximately 150 kDa.</p> Signup and view all the answers

<p>The heavy chain of an IgG antibody contains four domains.</p> Signup and view all the answers

<p>The variable regions confer the ability of antibodies to bind specific antigens.</p> Signup and view all the answers

<p>The ratio of λ to κ chains varies between species, indicating different distributions.</p> Signup and view all the answers

<p>An excess of λ light chains may indicate the presence of a B-cell tumor.</p> Signup and view all the answers

<p>The hinge region provides flexibility to the Y-shaped structure of antibodies.</p> Signup and view all the answers

<p>The five major classes are IgM, IgD, IgG, IgA, and IgE.</p> Signup and view all the answers

<p>The repetitive structure of immunoglobulin chains suggests they evolved from gene duplication.</p> Signup and view all the answers

<p>The V region is responsible for antigen specificity, while the C region has constant structure.</p> Signup and view all the answers

<p>The main components are two β sheets formed by β strands linked by a disulfide bridge.</p> Signup and view all the answers

<p>The variable (V) domain is larger and has an extra loop compared to the constant (C) domain.</p> Signup and view all the answers

<p>The flexible loops in the V domains form the antigen-binding site of the immunoglobulin molecule.</p> Signup and view all the answers

<p>These common amino acids are critical for the stability of the immunoglobulin fold.</p> Signup and view all the answers

<p>Immunoglobulin-like domains can be found in proteins involved in the immune system and cell-cell recognition in the nervous system.</p> Signup and view all the answers

<p>The immunoglobulin superfamily refers to a large group of proteins that include immunoglobulins and T-cell receptors, sharing similar structural domains.</p> Signup and view all the answers

<p>Crystallography has demonstrated the structural similarities of immunoglobulin-like domains across different proteins.</p> Signup and view all the answers

<p>The folded structure is characterized by a distinctive immunoglobulin fold, forming a barrel-shaped configuration.</p> Signup and view all the answers

<p>The two types of fragments are Fab fragments, which contain antigen-binding activity, and Fc fragments, which do not have antigen-binding activity.</p> Signup and view all the answers

<p>Papain cleaves on the amino-terminal side of the disulfide bonds, while pepsin cuts on the carboxy-terminal side of these bonds.</p> Signup and view all the answers

<p>The flexible hinge region allows independent movement of the Fab arms, enabling effective binding to antigens at varying distances.</p> Signup and view all the answers

<p>A single-chain Fv is a truncated Fab consisting of the V domain of a heavy chain linked by a synthetic peptide to a V domain of a light chain.</p> Signup and view all the answers

<p>Fab fragments consist of separate antigen-binding arms, while F(ab′)2 fragments have the two arms linked together.</p> Signup and view all the answers

<p>Fab fragments are small and can penetrate tissues readily, making them suitable for targeted therapies.</p> Signup and view all the answers

<p>Disulfide bonds link the heavy chains and contribute to the overall stability and integrity of the antibody structure.</p> Signup and view all the answers

<p>Both V and C domains share a similar folded structure, although there are distinct differences in their specific functions.</p> Signup and view all the answers

<p>Flexibility allows antibodies to effectively bind to haptens that are linked to larger proteins, enabling the stimulation of immune responses.</p> Signup and view all the answers

<p>The Fc fragment does not have antigen-binding activity but is essential for interacting with effector molecules in the immune system.</p> Signup and view all the answers

<p>Partial proteolysis can yield distinct fragments that affect the antibody's binding capacity and functional roles.</p> Signup and view all the answers

<p>The term refers to the flexible junction between the V and C domains, allowing bending and rotation for effective binding.</p> Signup and view all the answers

<p>Immunotoxins created from Fv molecules can specifically target tumor antigens, delivering toxic agents selectively to cancer cells.</p> Signup and view all the answers

<p>Higher antigen density can lead to improved cross-linking of antibody binding sites, enhanced by the flexibility of the hinge region.</p> Signup and view all the answers