Textbook Question
An epitope associates with which part of an antigen receptor or antibody?
a. The tail
b. The heavy-chain constant regions only
c. Variable regions of a heavy chain and light chain combined
d. The light-chain constant regions only
Ch. 43 - The Immune System
Urry11th EditionCampbell BiologyISBN: 9789357423311
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Table of contents
- Ch. 1 - Evolution, the Themes of Biology, and Scientific Inquiry8
- Ch. 2 - The Chemical Context of Life8
- Ch. 3 - Water and Life6
- Ch. 4 - Carbon and the Molecular Diversity of Life9
- Ch. 5 - The Structure and Function of Large Biological Molecules9
- Ch. 6 - A Tour of the Cell6
- Ch. 7 - Membrane Structure and Function6
- Ch. 8 - An Introduction to Metabolism6
- Ch. 9 - Cellular Respiration and Fermentation10
- Ch. 10 - Photosynthesis7
- Ch. 11 - Cell Communication7
- Ch. 12 - The Cell Cycle10
- Ch. 13 - Meiosis and Sexual Life Cycles10
- Ch. 14 - Mendel and the Gene Idea14
- Ch, 15 - The Chromosomal Basis of Inheritance7
- Ch. 16 - The Molecular Basis of Inheritance9
- Ch. 17 - Gene Expression: From Gene to Protein9
- Ch. 18 - Regulation of Gene Expression10
- Ch. 19 - Viruses6
- Ch. 20 - DNA Tools and Biotechnology8
- Ch. 21 - Genomes and Their Evolution8
- Ch. 22 - Descent with Modification: A Darwininan View of Life6
- Ch. 23 - The Evolution of Populations5
- Ch. 24 - The Origin of Species6
- Ch. 25 - The History of Life on Earth6
- Ch. 26 - Phylogeny and the Tree of Life7
- Ch. 27 - Bacteria and Archaea8
- Ch. 28 - Protists7
- Ch. 29 - Plant Diversity I: How Plants Colonized Land7
- Ch. 30 - Plant Diversity II: The Evolution of Seed Plants7
- Ch. 31 - Fungi5
- Ch. 32 - An Overview of Animal Diversity4
- Ch. 33 - An introduction to Invertebrates6
- Ch. 34 - The Origin and Evolution of Vertebrates7
- Ch. 35 - Vascular Plant Structure, Growth, and Development8
- Ch. 36 - Resource Acquisition and Transport in Vascular Plants8
- Ch. 37 - Soil and Plant Nutrition10
- Ch. 38 - Angiosperm Reproduction and Biotechnology8
- Ch. 39 - Plant Responses to Internal and External Signals8
- Ch. 40 - Basic Principles of Animal Form and Function8
- Ch. 41 - Animal Nutrition7
- Ch. 42 - Circulation and Gas Exchange7
- Ch. 43 - The Immune System6
- Ch. 44 - Osmoregulation and Excretion6
- Ch. 45 - Hormones and the Endocrine System8
- Ch. 46 - Animal Reproduction8
- Ch. 47 - Animal Development8
- Ch. 48 - Neurons, Synapses, and Signaling6
- Ch. 49 - Nervous Systems8
- Ch. 50 - Sensory and Motor Mechanisms5
- Ch. 51 Animal Behavior6
- Ch. 52 - An Introduction to Ecology and the Biosphere7
- Ch. 53 - Population Ecology10
- Ch. 54 - Community Ecology9
- Ch. 55 - Ecosystems and Restoration Ecology8
- Ch. 56 - Conservation Biology and Global Change6
Chapter 43, Problem 4
Which of the following statements is true?
a. An antibody has one antigen-binding site
b. A lymphocyte has receptors for a single antigen
c. Every antigen has a single epitope
d. A liver or muscle cell makes two classes of MHC molecule
Verified step by step guidance1
Step 1: Understand the key terms in the question. An antibody is a protein produced by B cells that binds specifically to antigens. Antigens are molecules that elicit an immune response, and epitopes are the specific parts of an antigen that antibodies or receptors bind to. MHC (Major Histocompatibility Complex) molecules are proteins on the surface of cells that present antigens to T cells.
Step 2: Evaluate statement (A): 'An antibody has one antigen-binding site.' Recall that antibodies are Y-shaped molecules with two identical antigen-binding sites, one on each arm of the Y. This makes statement (A) false.
Step 3: Evaluate statement (B): 'A lymphocyte has receptors for a single antigen.' Lymphocytes (B cells and T cells) are highly specific and typically have receptors that recognize only one specific antigen. This makes statement (B) true.
Step 4: Evaluate statement (C): 'Every antigen has a single epitope.' Antigens can have multiple epitopes, allowing different antibodies or receptors to bind to different parts of the antigen. This makes statement (C) false.
Step 5: Evaluate statement (D): 'A liver or muscle cell makes two classes of MHC molecule.' Liver and muscle cells are not immune cells and typically express only MHC class I molecules, not both classes. This makes statement (D) false.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Antibodies and Antigen-Binding Sites
Antibodies are proteins produced by B cells that specifically bind to antigens, which are foreign substances that trigger an immune response. Each antibody typically has two identical antigen-binding sites, allowing it to bind to two identical epitopes on an antigen, enhancing its ability to neutralize pathogens.
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Lymphocyte Receptors
Lymphocytes, including B cells and T cells, have specific receptors that recognize and bind to particular antigens. Each lymphocyte is programmed to recognize a single antigen, which allows for a highly specific immune response. This specificity is crucial for the adaptive immune system's ability to target diverse pathogens.
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Epitopes and Antigens
An epitope is the specific part of an antigen that is recognized by the immune system, particularly by antibodies or T cell receptors. Antigens can have multiple epitopes, meaning they can be recognized by different antibodies or T cells, which allows for a robust immune response against a single pathogen.
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Related Practice
Textbook Question
Which statement best describes the difference between responses of effector B cells (plasma cells) and those of cytotoxic T cells?
a. B cells confer active immunity; cytotoxic T cells confer passive immunity.
b. B cells respond the first time a pathogen is present; cytotoxic T cells respond subsequent times.
c. B cells secrete antibodies against a pathogen; cytotoxic T cells kill pathogen-infected host cells.
d. B cells carry out the cell-mediated response; cytotoxic T cells carry out the humoral response.
Textbook Question
Which of the following statements is not true?
a. An antibody has more than one antigen-binding site.
b. A lymphocyte has receptors for multiple different antigens.
c. An antigen can have different epitopes.
d. A liver or muscle cell makes one class of MHC molecule.
Textbook Question
Which of the following should be the same in identical twins?
a. The set of antibodies produced
b. The set of MHC molecules produced
c. The set of T cell antigen receptors produced
d. The set of immune cells eliminated as self-reactive