Microbiology Review Flashcards

Questions and Answers

What is the primary difference between an antigen and an antibody?

An antigen is a type of white blood cell, while an antibody is a toxin.

An antigen stimulates an immune response, while an antibody is produced in response to an antigen. (correct)

An antibody binds to bacteria, while an antigen binds to viruses.

Antigens are produced by the body, but antibodies are not.

What is immunity?

The ability of an organism to resist a particular infection or toxin by the action of specific antibodies or sensitized white blood cells.

Differentiate between agglutination, opsonization, and neutralization.

Agglutination enhances phagocytosis; opsonization coats antigens with antibodies to enhance phagocytosis; neutralization blocks adhesion of bacteria and viruses.

Which of the following are the 4 main types of T cells?

Cytotoxic T cells Signup and view all the answers

Why does the immune system not react to the body's own cells?

The body recognizes its own cells and does not produce antigens against them. Signup and view all the answers

What is the function of MHC (Major Histocompatibility Complex) molecules?

To bind peptide fragments from pathogens and display them for recognition by T-cells. Signup and view all the answers

How do plasma cells and memory B cells differ?

Plasma cells produce the first wave of antibodies; memory B cells remember the infection for quicker response later. Signup and view all the answers

Explain the Clonal Selection Theory as it applies to B cells.

It describes how B cells respond quickly to a pathogen upon re-exposure and differentiate into plasma or memory B cells. Signup and view all the answers

How is a T cell activated by a macrophage?

A T cell requires an antigen-presenting cell like a macrophage, which displays the antigen on its MHC proteins. Signup and view all the answers

Describe the primary and secondary immune response of IgG to a vaccine.

Primary response occurs after vaccination with a lag for antibody production; secondary response is faster due to memory B cells. Signup and view all the answers

Differentiate between antibody-mediated immunity (humoral immunity) and cell-mediated immunity.

Humoral immunity involves B cells producing antibodies in response to antigens; cell-mediated immunity involves T cells attacking infected cells. Signup and view all the answers

Study Notes

Antigens and Antibodies

Antigens stimulate an immune response.
Antibodies are proteins created in response to antigens.
Antibodies specifically recognize and bind to their corresponding antigens.

Immunity

Refers to an organism's ability to resist specific infections or toxins.
Involves actions by particular antibodies or sensitized white blood cells.

Protective Mechanisms of Antibodies

Agglutination: Antibodies bind to multiple antigens, enhancing phagocytosis and reducing infectious units.
Opsonization: Antibodies coat antigens, facilitating their recognition and uptake by phagocytes.
Neutralization: Antibodies block pathogens from adhering to host cells and prevent toxin activity.

Types of T Cells

Helper T cells: Assist other immune cells.
Cytotoxic T cells: Target and kill infected cells.
Memory T cells: Provide a rapid response upon re-exposure to an antigen.
Suppressor T cells: Regulate the immune response to prevent overactivity.

Immune Tolerance

The immune system distinguishes between self and foreign cells using specific antigens.
Self-recognition prevents the immune attack on the body’s own cells.

Major Histocompatibility Complex (MHC)

MHC molecules display peptide fragments from pathogens on infected cells.
Essential for T cell recognition and activation within the adaptive immune system.

B Cells: Plasma vs. Memory

Plasma cells are differentiated B cells producing initial antibodies against infection.
Memory B cells are created by further differentiation for prolonged immunity to previously encountered pathogens.

Clonal Selection Theory

Explains the rapid immune response to subsequent exposures to a pathogen.
B cells can clone themselves and differentiate into plasma or memory cells for effective response.

T Cell Activation Process

Requires antigen-presenting cells like macrophages or B cells displaying antigens on MHC proteins.
Helper T cells are activated upon recognizing specific antigens; memory T cells enable quick responses to re-exposure.

Immune Responses to Vaccination

Primary response: Initial exposure to a vaccine leads to no immediate antibody production while B cells are activated.
Secondary response: Occurs upon later exposure when memory B cells facilitate a quicker and more robust antibody response.

Types of Immunity

Humoral Immunity (Antibody-mediated): Involves B cells producing antibodies after encountering an antigen, assisted by helper T cells.
Cell-mediated Immunity: Targets pathogens that invade host cells, acting through T cells and other immune mechanisms.

Description

Test your knowledge on key microbiology concepts with these flashcards. This quiz covers essential terms such as antigens, antibodies, and the basics of immunity. Perfect for reinforcing your understanding of the immune system.