Textbook Question
Mark the following statements as true or false. If a statement is false, correct is to make a true statement.
Subunit vaccines consist of pathogens that are alive but unable to cause disease.
922
views
21. The Immune System
Classes of Antibodies
Problem 4
Textbook Question
The specificity of an antibody is determined by the
(a) Fixed segment
(b) Antigenic determinants
(c) Variable region
(d) Size of the antibody
(e) Antibody class
Verified step by step guidance1
Understand that an antibody is a Y-shaped protein used by the immune system to identify and neutralize foreign objects like bacteria and viruses.
Recall that antibodies have different regions: the fixed (constant) region and the variable region. The fixed region determines the class of the antibody, while the variable region is responsible for binding to specific antigens.
Recognize that antigenic determinants, also called epitopes, are specific parts of an antigen that antibodies bind to, but they do not determine the antibody's specificity; rather, they are the target of the antibody.
Identify that the specificity of an antibody is determined by the structure of its variable region, which varies between different antibodies to recognize different antigens.
Conclude that among the given options, the variable region (option c) is the correct answer because it determines the unique antigen-binding specificity of the antibody.
Verified video answer for a similar problem:This video solution was recommended by our tutors as helpful for the problem above
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Antibody Structure
Antibodies are Y-shaped proteins composed of variable and constant regions. The variable region, located at the tips of the Y, is responsible for binding to specific antigens, while the constant region determines the antibody's class and effector functions.
Recommended video:
5:40
Antibody Structure
Variable Region
The variable region of an antibody contains unique amino acid sequences that create a specific binding site for an antigen. This region's diversity allows antibodies to recognize a vast array of antigens with high specificity.
Recommended video:
Guided course
04:21The 9 Abdominopelvic Regions
Antigenic Determinants (Epitopes)
Antigenic determinants, or epitopes, are specific parts of an antigen recognized and bound by an antibody's variable region. The interaction between the variable region and these epitopes determines the antibody's specificity.
Recommended video:
3:59Antigens
Related Videos
Related Practice
![](https://media.pearsoncmg.com/bc/bc_0media_ap/ala/mechanisms-of-antibody-action/usolver/preview.html#/file/"../files/5b07ec4891f1055047653bdf.usolver")