Mastering Microbiology Chapter 17 HW

Questions and Answers

Mucous membranes are a part of?

innate defense.

According to the animation, B cells interact directly with?

helper T cells.

Which of the following defense systems would be involved in eliminating virally-infected cells?

T lymphocytes (correct)

Phagocytes

B lymphocytes

Natural killer cells

According to the animation, antibodies directly interact with which innate defenses?

Phagocytosis and the complement system. Signup and view all the answers

Which cells directly attack abnormal cells in the body?

Cytotoxic T cells. Signup and view all the answers

What is the role of helper T cells in the adaptive immune response?

Helper T cells activate B cells and cytotoxic T lymphocytes to kill infected host cells. Signup and view all the answers

What is meant by the clonal expansion of a B cell?

An activated B cell divides into cells that give rise to memory B cells and plasma cells. Signup and view all the answers

What component of the immune system will protect someone from getting the same cold again after exposure to the same Rhinovirus?

Memory B cells. Signup and view all the answers

Correctly order the steps involved in cellular immunity: 1.) The Tc recognizes the infected host cell; 2.) The Tc interacts with epitope presented by MHC-I on the dendritic cell; 3.) The Tc secretes perforin and granzyme, causing apoptosis; 4.) The helper T cell activates the Tc cell.

2, 4, 1, 3 Signup and view all the answers

Which of the following is NOT a step used by cytotoxic T cells to kill infected host cells?

Recognition of infected host cell using its CD4 glycoprotein Signup and view all the answers

Place the following steps of phagocytosis in the order that they occur: 1) Endosome fuses with lysozome; 2) Dendritic cell engulfs Rhinovirus; 3) Epitopes are attached to MHC-II; 4) Digestion of the Rhinovirus; 5) MHC-II plus the attached epitope move to the outside of the dendritic cell.

2, 1, 4, 3, 5 Signup and view all the answers

Which pair of molecules do NOT directly interact with one another?

BCR and TCR Signup and view all the answers

Which of the following is NOT a step that ultimately leads to antibody production?

Activation of cytotoxic T cells by helper T cells Signup and view all the answers

What component of the immune response still responds to antigen despite a low helper T cell count in someone with AIDS?

Clonal selection of B cells. Signup and view all the answers

Adaptive defenses include both humoral and cellular immunity.

True Signup and view all the answers

Antigen processing and presentation is a way for a cell to give information about its activities.

true Signup and view all the answers

Why would a body cell that is not a phagocyte need to present antigens?

Non-phagocytic body cells can become infected with a virus. Signup and view all the answers

How do phagocytes communicate to other cells what they have captured?

They present antigens from engulfed foreign cells. Signup and view all the answers

Which receptor on the helper T-cell recognizes the specific antigen from an antigen-presenting cell?

TCR. Signup and view all the answers

Which proteins on the antigen-presenting cell are recognized by the helper T-cell?

MHC proteins. Signup and view all the answers

When do helper T-cells develop into TH1 or TH2 cells?

After proliferation into a clonal population. Signup and view all the answers

Natural killer cells are activated by?

TH1 cells. Signup and view all the answers

What is apoptosis?

The process of programmed cell death. Signup and view all the answers

What is the function of the CD8 receptor?

Bind to MHC molecules. Signup and view all the answers

What is the fate of activated cytotoxic T-cells?

They proliferate into a clone of cells specific to the same antigen; some of these cells then differentiate into long-lived memory T-cells, while others mature to attack infected cells. Signup and view all the answers

Which molecule triggers apoptosis?

Granzyme. Signup and view all the answers

Which event happens first during cytotoxic T-cell activation?

CD8 binds to MHC molecules of infected cells. Signup and view all the answers

The primary immune response involves?

a slow rise in the concentration of antibodies, followed by a gradual decline. Signup and view all the answers

According to the animation, for approximately how many days is IgG present in the serum?

Ten days. Signup and view all the answers

Study Notes

Innate Defense

Mucous membranes are integral components of the innate defense system.

B and T Cells Interaction

B cells interact directly with helper T cells to coordinate immune responses.
T lymphocytes are responsible for eliminating virally-infected cells.

Antibodies and Innate Defenses

Antibodies facilitate phagocytosis and activate the complement system during immune responses.

Cytotoxic Activity

Cytotoxic T cells are specialized for directly attacking abnormal cells.
Helper T cells play a crucial role in activating B cells and cytotoxic T lymphocytes.

Clonal Expansion

Clonal expansion refers to the process where an activated B cell divides, producing memory B cells and plasma cells.

Immunological Memory

Memory B cells protect individuals from recurrent infections by the same pathogen, such as Rhinovirus.

Cellular Immunity Steps

The sequence of cellular immunity involves recognizing infected host cells, interaction with antigens, and the secretion of substances leading to apoptosis.

Phagocytosis Process

The steps of phagocytosis include the engulfment of pathogens, fusion with lysosomes, digestion, and presentation of epitopes on MHC-II.

Antibody Production

Antibody production does not involve the activation of cytotoxic T cells by helper T cells.

Function of Helper T Cells

Despite low counts of helper T cells, some immune responses like the clonal selection of B cells can still occur.

Adaptive Immunity

Adaptive defenses encompass both humoral immunity (antibody-mediated) and cellular immunity (T cell-mediated).

Antigen Presentation

Antigen processing allows cells to communicate their activity status to the immune system; non-phagocytic cells can present antigens when infected.

Phagocyte Communication

Phagocytes communicate captured foreign materials to other immune cells by presenting antigens.

Antigen Recognition

Helper T cells recognize specific antigens via TCR (T Cell Receptor), engaging with MHC proteins on antigen-presenting cells.

TH1 and TH2 Cells

Helper T cells differentiate into TH1 or TH2 cells after proliferating into a clonal population.

Natural Killer Cells Activation

Natural killer (NK) cells are activated by signals from TH1 cells.

Apoptosis

Apoptosis is the programmed process of cell death essential for eliminating damaged or infected cells.

CD8 Receptor Function

The CD8 receptor binds to MHC molecules on infected cells, facilitating T cell activation.

Fate of Cytotoxic T Cells

Activated cytotoxic T cells proliferate into clones specific to their antigen, some becoming long-lived memory T cells while others attack infected cells.

Apoptosis Trigger

Granzyme is the molecule responsible for inducing apoptosis in target cells.

Cytotoxic T Cell Activation

The initial event in cytotoxic T cell activation is the binding of CD8 to MHC molecules on infected cells.

Primary Immune Response

The primary immune response is characterized by a slow rise and subsequent decline in antibody concentrations.

Duration of IgG in Serum

IgG antibodies remain present in the serum for approximately ten days following their response.

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Test your knowledge with these flashcards from Chapter 17 of Mastering Microbiology. This quiz covers essential concepts such as innate defense mechanisms, B cell interactions, and the roles of T lymphocytes in immune response. Perfect for reinforcing your understanding of microbiology.