Immune Response and Cell Signaling

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Questions and Answers

What type of hormones rely on intracellular receptor proteins to function?

Peptide hormones

Eicosanoids

Water-soluble hormones

Steroid hormones (correct)

Where does the hormone-receptor complex bind to stimulate transcription?

Target gene in the nucleus (correct)

Plasma membrane

Cytoplasm

Endoplasmic reticulum

What happens to mRNA after it is generated by the hormone-receptor complex?

It breaks down immediately.

It is translated into a specific protein. (correct)

It circulates in the bloodstream.

It is stored in the cytoplasm indefinitely.

Which of the following are examples of thyroid hormones?

Thyroxine and triiodothyronine Signup and view all the answers

In the cellular signaling process, where does the hormone first bind after passing through the plasma membrane?

Receptor protein in the cytoplasm Signup and view all the answers

What is the main role of B cells in the immune response?

To present antigens to T helper cells Signup and view all the answers

Which type of signaling involves a cell responding to molecules it secretes itself?

Autocrine signaling Signup and view all the answers

What is the function of interleukin-1 (IL-1) in monocytes?

To bind to receptors on the same cell Signup and view all the answers

What occurs after a T cell receptor recognizes a foreign antigen?

The T cell activates and signals other immune cells Signup and view all the answers

What is the end result of B cell maturation?

The release of antibodies into the blood Signup and view all the answers

Which type of signaling involves molecules acting on neighboring cells?

Paracrine signaling Signup and view all the answers

What distinguishes synaptic signaling from other types?

It requires a physical connection between cells Signup and view all the answers

Which cell type primarily performs phagocytosis?

Macrophages Signup and view all the answers

What is crucial for a cell's ability to respond to signals?

The collection of different receptors Signup and view all the answers

How do extracellular signals affect a cell?

By altering the activity of cell proteins Signup and view all the answers

What happens if a cell does not receive any signals?

The cell must die Signup and view all the answers

What role does a receptor protein play in signaling?

It binds to the signal molecule Signup and view all the answers

What is a second messenger in the context of cellular signaling?

An intracellular signaling pathway mediator Signup and view all the answers

How do signaling cascades function in a cell?

They convert signals into a suitable molecular form Signup and view all the answers

What is a possible consequence of altering target proteins in a signaling pathway?

A change in the behavior of the cell Signup and view all the answers

What must happen for a signaling response to be produced in a cell?

The signal must be transmitted to the point of response Signup and view all the answers

What is the main role of most steroid receptors in cellular signaling?

Regulate transcription and gene expression Signup and view all the answers

How do extracellular signal molecules affect cell responses?

They can lead to fast or slow responses depending on the signal. Signup and view all the answers

Where are intracellular receptors typically located before a ligand binds?

In the cytoplasm Signup and view all the answers

Which type of signaling involves altered protein synthesis and changes in gene expression?

Slow responses related to cell growth and division Signup and view all the answers

What characteristic do all extracellular signal molecules share?

They can vary widely, including proteins, nucleotides, and gases. Signup and view all the answers

What happens to intracellular receptors upon ligand binding?

They enter the nucleus. Signup and view all the answers

Which of the following is true about hydrophobic signal molecules?

They are lipid-soluble and can pass through cell membranes. Signup and view all the answers

What distinguishes the function of cytosolic receptors from nuclear receptors?

Cytosolic receptors often act faster and may not involve gene expression. Signup and view all the answers

What is one of the functional domains of a steroid receptor?

Ligand-binding domain Signup and view all the answers

What role does the DNA binding domain of a steroid receptor play?

To activate gene expression after binding to DNA Signup and view all the answers

What is a characteristic of the Steroid Receptor Superfamily?

They function as either activators or repressors of transcription Signup and view all the answers

What triggers smooth muscle relaxation in a blood-vessel wall?

Nitric oxide Signup and view all the answers

How does nitric oxide signal within the target cell?

By diffusing into cells and binding directly to an enzyme Signup and view all the answers

What molecule does guanylyl cyclase catalyze the production of in response to nitric oxide?

cGMP Signup and view all the answers

What is the initial signal that leads to nitric oxide production in this signaling pathway?

Acetylcholine is released from nerve cells Signup and view all the answers

What effect does cGMP have in smooth muscle cells following nitric oxide signaling?

It leads to muscle relaxation Signup and view all the answers

Study Notes

Immune Response

Macrophages engulf bacteria through phagocytosis.
Macrophages present bacterial antigens to T lymphocytes.
T lymphocytes activate and release cytokines.
Cytokines signal B lymphocytes to mature.
Mature B lymphocytes differentiate into plasma cells.
Plasma cells secrete antibodies that bind to specific antigens.

### Cell Signaling

Cells communicate through signaling molecules.
Autocrine signaling: cells respond to signaling molecules they produce.
Paracrine signaling: cells respond to signaling molecules produced by neighboring cells.
Synapse signaling: cells communicate through neurotransmitters.
Cell receptors are programmed to respond to specific signal molecules.
Signal molecules activate a series of intracellular signaling proteins.
Intracellular signaling pathways alter target proteins, changing cell behavior.
Signals can trigger changes in protein function or gene expression.

### Types of Signals

Signals molecules can be proteins, peptides, amino acids, nucleotides, steroids, fatty acid derivatives, and dissolved gases.
Signal molecules bind to cell-surface receptors or intracellular receptors.

Intracellular Receptors

Intracellular receptors are cytoplasmic or nuclear proteins.
Signal molecules are lipid-soluble molecules.
Steroid receptors have three functional domains: a hormone-binding domain, a DNA-binding domain, and a coactivator-binding domain.
Steroid receptors bind to specific DNA sequences and regulate gene expression.

### Cell Signaling by Hydrophobic Signals

Nitric oxide (NO) triggers smooth muscle relaxation in blood vessels.
NO diffuses across cell membranes and binds to intracellular enzymes, affecting target enzymes.
NO signaling causes blood vessels dilate.

### Steroid Hormones

Steroid hormones bind to intracellular receptors, forming a hormone-receptor complex.
The hormone-receptor complex translocates to the nucleus.
The complex binds to specific DNA sequences and regulates gene expression.

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Description

Explore the mechanisms of the immune response and the various types of cell signaling in this quiz. Understand how macrophages, T lymphocytes, and B lymphocytes coordinate to defend the body, as well as how cells communicate through different signaling methods. Test your knowledge on the intricate processes involved in these biological interactions.