Cell Signaling Quiz: Communication Methods and Pathways

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Questions and Answers

Cellular communication relies on the interaction between ______ signals and specific cell surface receptors

chemical

The mobilization of diffusible intracellular second-messenger systems is a secondary event triggered by the binding of ______ messengers to cell surface receptors

chemical

Hydrophobic messengers, such as ______ hormones, can diffuse across the plasma membrane and interact with cytosolic or nuclear receptors

steroid

Cells use a number of different, often intersecting ______ signaling pathways to ensure that the cell's response to a stimulus is tightly controlled

intracellular Signup and view all the answers

Early insight into signal transduction pathways was obtained from studies of the ______ system

endocrine Signup and view all the answers

Communication among cells is fundamental to all ______ processes, ranging from the induction of embryonic development to the integration of physiological responses in the face of environmental challenges

biological Signup and view all the answers

External signals such as odorants, chemicals that reflect metabolic status, ions, hormones, growth factors, and neurotransmitters can all serve as ______ messengers linking neighboring or distant cells

chemical Signup and view all the answers

The classic definition of a hormone is a substance that is produced in one tissue or organ and released into the blood and carried to other organs (targets), where it acts to produce a specific ______.

response Signup and view all the answers

The idea of endocrine or ductless glands developed from the recogni- tion that certain organs—such as the pituitary, adrenal, and thyroid gland—can synthesize and release specific chemical messengers in response to particular ______ states.

physiological Signup and view all the answers

Receptors can be divided into four categories on the basis of their associated mechanisms of signal ______.

transduction Signup and view all the answers

Ligand-gated ion channels. Integral membrane pro- teins, these hybrid receptor/channels are involved in sig- naling between electrically excitable ______.

cells Signup and view all the answers

G protein–coupled receptors. These integral plasma membrane proteins work indirectly—through an ______—to activate or to inactivate a separate mem- brane-associated enzyme or channel.

intermediary Signup and view all the answers

Catalytic receptors. When activated by a ligand, these integral plasma membrane proteins are either enzymes themselves or part of an ______ complex.

enzymatic Signup and view all the answers

Nuclear receptors. These proteins, located in the cytosol or nucleus, are ______-activated transcription factors.

ligand Signup and view all the answers

Second-messenger systems amplify signals and integrate responses among cell types. Once a signal has been received at the cell surface, it is typically amplified and transmitted to specific sites within the cells through ______.

second messengers Signup and view all the answers

For a molecule to function as a ______, its concentration, or window of activity, must be finely regulated.

second messenger Signup and view all the answers

The cell achieves this control by rapidly producing or activating the ______ messenger and then inactivating or degrading it.

second Signup and view all the answers

To ensure that the system returns to a resting state when the stimulus is removed, ______ activities function at each step of the cascade.

counterbalancing Signup and view all the answers

The involvement of second messengers in catalytic cascades provides numerous opportunities to ______ a signal.

amplify Signup and view all the answers

For example, the binding of a ligand to its receptor can generate hundreds of ______ molecules, which can in turn alter the activity of thousands of downstream effectors.

second-messenger Signup and view all the answers

An example of such a cascade is the increased intracellular concentration of the second messenger ______.

cAMP Signup and view all the answers

Receptor occupancy activates a G protein, which in turn stimulates a membrane-bound enzyme, ______.

adenylyl cyclase Signup and view all the answers

This enzyme catalyzes the synthesis of from adenosine triphosphate (ATP), and a 5-fold increase in the intracellular concentration of is achieved in approximately 5 seconds.

cAMP Signup and view all the answers

This sudden rise in cAMP levels is rapidly counteracted by its breakdown to adenosine 5’-monophosphate by ______.

cAMP phosphodiesterase Signup and view all the answers

Gap junctions facilitate the passage of inorganic ions and small molecules, such as Ca2+ and 3',5'-cyclic adenosine monophosphate (cAMP), from the cytoplasm of one cell into the cytoplasm of an adjacent cell. Mammalian gap junctions permit the passage of molecules that are less than _ Da but restrict the movement of molecules that are greater than _ Da.

1200, 2000 Signup and view all the answers

The permeability of gap junctions can be rapidly regulated by changes in cytosolic concentrations of Ca2+, cAMP, and H+ as well as by the voltage across the cell membrane or membrane potential (Vm). This type of modulation is physiologically important for cell-to-cell _____

communication Signup and view all the answers

Adhering junctions form as the result of the Ca2+-dependent interactions of the extracellular domains of transmembrane proteins called _____

cadherins Signup and view all the answers

The clustering of cadherins at the site of interaction with an adjacent cell causes secondary clustering of intracellular proteins known as _____, which in turn serve as sites of attachment for the intracellular actin cytoskeleton.

catenins Signup and view all the answers

Disruption of adhering junctions by certain growth factors causes ___ to dissociate from cadherin. The resulting rise in free _ levels promotes the translocation of _ to the nucleus. There, ___ regulates the transcription of multiple genes, including ones that promote cell proliferation and migration.

β-catenin, β-catenin, β-catenin, β-catenin Signup and view all the answers

Tight junctions comprise transmembrane proteins that link with their counterparts on adjacent cells as well as intracellular proteins that stabilize the complex and also have a signaling role. The transmembrane proteins—including claudins, occludin, and junctional adhesion molecule—and their extracellular domains create the diffusion barrier of the tight junction. One of the integral cytoplasmic proteins in tight junctions, zonula occludin 1 (ZO-1), colocalizes with a serine/threonine kinase known as _____, which is found in certain renal tubule epithelial cells that reabsorb Na+ and Cl- from the tubule lumen.

WNK1 Signup and view all the answers

Membrane-associated ligands provide spatial clues in migrating cells. For example, an ephrin ligand expressed on the surface of one cell can interact with an Eph receptor on a nearby cell. The resulting activation of the Eph receptor can in turn provide signals for regulating such developmental events as axonal guidance in the nervous system and endothelial cell guidance in the vasculature. This mechanism of direct cell communication involves the interaction of a receptor in the plasma membrane with a ligand that is itself a membrane protein on an adjacent cell, known as _____

membrane-associated ligands Signup and view all the answers

Which one of these is the equation for a line in slope-intercept form?

$y = mx + b$ Signup and view all the answers

Which one of these is the equation for a quadratic function?

$y = ax^2 + bx + c$ Signup and view all the answers

Which one of these is the equation for an inverse function?

$y = \frac{1},{x}$ Signup and view all the answers

Which one of these is the equation for a square root function?

$y = \sqrt{x}$ Signup and view all the answers

Which of the following is a characteristic of membrane-bound enzymes?

They are activated by ligands Signup and view all the answers

Which of the following is true about catalytic receptors?

They are enzymes themselves Signup and view all the answers

What is the secondary event triggered by the binding of messengers to cell surface receptors?

Mobilization of diffusible intracellular second-messenger systems Signup and view all the answers

What is the primary function of catalytic receptors?

Activation of membrane-bound enzymes Signup and view all the answers

What are the integral plasma membrane proteins involved in catalytic receptors?

Membrane-bound enzymes Signup and view all the answers

What triggers the activation of catalytic receptors?

The binding of messengers to cell surface receptors Signup and view all the answers

What is the primary function of membrane-bound enzymes?

Formation of a complex Signup and view all the answers

Which type of messengers can diffuse across the plasma membrane and interact with cytosolic or nuclear receptors?

Hydrophobic messengers Signup and view all the answers

What do most chemical messengers interact with to trigger a cascade of secondary events?

Cell surface receptors Signup and view all the answers

What type of signaling pathways do cells use to ensure a tightly controlled response to a stimulus?

Intersecting signaling pathways Signup and view all the answers

What type of messengers can serve as chemical messengers linking neighboring or distant cells?

All of the above Signup and view all the answers

What are the secondary events triggered by the binding of chemical messengers to cell surface receptors?

All of the above Signup and view all the answers

What type of proteins stabilize tight junctions and have a signaling role?

ZO-1 Signup and view all the answers

What type of receptors work indirectly to activate or inactivate a separate membrane-associated enzyme or channel?

G protein-coupled receptors Signup and view all the answers

Which of the following equations represents a linear function?

$f(x) = -4(x + 3)2 + 2$ Signup and view all the answers

Which of the following is the equation of a parabola?

$f(x) = 5x^2 + 3x - 2$ Signup and view all the answers

Which of the following equations represents an exponential function?

$f(x) = 2^x$ Signup and view all the answers

Which of the following equations represents an inverse function?

$f(x) = \frac{1},{x}$ Signup and view all the answers

Which of the following equations represents a quadratic function?

$f(x) = 5x^2 + 3x - 2$ Signup and view all the answers

Which of the following is NOT considered a chemical messenger in cellular communication?

Light Signup and view all the answers

Hydrophobic messengers, such as steroid hormones, can diffuse across the plasma membrane and interact with ______ receptors.

Nuclear Signup and view all the answers

What type of signaling pathways do cells use to ensure a tightly controlled response to a stimulus?

Intersecting Signup and view all the answers

Which of the following equations represents an exponential function?

$f(x) = 2^x$ Signup and view all the answers

What is the primary function of membrane-bound enzymes?

Signal transduction Signup and view all the answers

Receptors can be divided into four categories on the basis of their associated mechanisms of signal ______.

Transduction Signup and view all the answers

What is the secondary event triggered by the binding of messengers to cell surface receptors?

Mobilization of second-messenger systems Signup and view all the answers

Which of the following is NOT one of the four categories of receptors based on their associated mechanisms of signal transduction?

Ligand-gated ion channels Signup and view all the answers

What is the primary function of G protein–coupled receptors?

To directly activate or inactivate membrane-associated enzymes or channels Signup and view all the answers

Which of the following is NOT a step in the signaling events initiated by plasma membrane receptors?

Modulation of the effector Signup and view all the answers

What type of messengers can diffuse across the plasma membrane and interact with cytosolic or nuclear receptors?

Hydrophobic messengers Signup and view all the answers

What are the secondary events triggered by the binding of chemical messengers to cell surface receptors?

Generation of second messengers Signup and view all the answers

Which of the following is NOT a characteristic of membrane-bound enzymes?

They are involved in signaling between electrically excitable cells Signup and view all the answers

Receptor occupancy activates a G protein, which in turn stimulates a membrane-bound enzyme, ______.

Catalytic receptor Signup and view all the answers

Which of the following is a characteristic of second messengers?

They are rapidly produced or activated and then inactivated or degraded Signup and view all the answers

What is the role of second messengers in signal transduction?

Amplify signals and integrate responses among cell types Signup and view all the answers

Which of the following is an example of a second messenger cascade?

Increased intracellular concentration of cAMP Signup and view all the answers

What is the function of G protein in signal transduction?

To activate a membrane-bound enzyme Signup and view all the answers

Which of the following is true about ligands that activate the same signaling pathways in cells?

They usually produce the same effect Signup and view all the answers

What is the role of second-messenger systems in a multicellular organism?

To coordinate the response to a stressful situation Signup and view all the answers

What triggers the activation of catalytic receptors?

Ligand binding Signup and view all the answers

What is the function of counterbalancing activities in second-messenger systems?

To ensure the system returns to a resting state Signup and view all the answers

What allows ligands to produce distinct responses in different cells?

Distinct receptors and signal transduction pathways Signup and view all the answers

Which of the following is true about gap junctions?

They can be regulated by changes in cytosolic concentrations of Ca2+, cAMP, and H+ Signup and view all the answers

What is the function of adhering junctions?

Maintenance of normal cell architecture and organization of groups of cells into tissues Signup and view all the answers

Which of the following is true about tight junctions?

They can determine the permeability of the tight junctions to Cl- Signup and view all the answers

Which of the following is true about membrane-associated ligands?

They can interact with an adjacent cell's receptor Signup and view all the answers

What is the primary function of catalytic receptors?

Act as enzymes Signup and view all the answers

Which of the following is true about hydrophobic messengers?

They can diffuse across the plasma membrane and interact with cytosolic or nuclear receptors Signup and view all the answers

What are the secondary events triggered by the binding of chemical messengers to cell surface receptors?

Activation of intracellular proteins Signup and view all the answers

Which of the following is NOT a type of chemical messenger in cellular communication?

Light Signup and view all the answers

What is the primary function of membrane-bound enzymes?

To catalyze chemical reactions at the plasma membrane Signup and view all the answers

Which of the following is the equation of a parabola?

$y = ax^2 + bx + c$ Signup and view all the answers

What triggers the activation of catalytic receptors?

Ligands Signup and view all the answers

What is the function of G protein in signal transduction?

To trigger a cascade of secondary events Signup and view all the answers

Which of the following equations represents an exponential function?

$y = e^x$ Signup and view all the answers

What is the secondary event triggered by the binding of messengers to cell surface receptors?

Mobilization of second-messenger systems Signup and view all the answers

Which of the following is NOT a characteristic of second messengers?

They integrate responses among cell types Signup and view all the answers

What is the primary function of second messengers in signal transduction?

To amplify signals Signup and view all the answers

Which of the following equations represents a quadratic function?

$f(x) = x^2 + 5x - 2$ Signup and view all the answers

What type of signaling pathways do cells use to ensure a tightly controlled response to a stimulus?

Second-messenger systems Signup and view all the answers

What are the integral plasma membrane proteins involved in catalytic receptors?

G-proteins Signup and view all the answers

What is the function of adhering junctions?

To provide mechanical strength and stability to tissues Signup and view all the answers

What is the role of second messengers in signal transduction?

To amplify signals Signup and view all the answers

Which of the following equations represents an exponential function?

$f(x) = e^x$ Signup and view all the answers

What allows ligands to produce distinct responses in different cells?

Specialized functions of the cells Signup and view all the answers

Which of the following is NOT a step in the signaling events initiated by plasma membrane receptors?

Response of the cell to the initial stimulus Signup and view all the answers

What do most chemical messengers interact with to trigger a cascade of secondary events?

Plasma membrane receptors Signup and view all the answers

G protein–coupled receptors. These integral plasma membrane proteins work indirectly—through an ______—to activate or to inactivate a separate mem- brane-associated enzyme or channel.

G protein Signup and view all the answers

Gap junctions facilitate the passage of inorganic ions and small molecules, such as Ca2+ and 3',5'-cyclic adenosine monophosphate (cAMP), from the cytoplasm of one cell into the cytoplasm of an adjacent cell. Mammalian gap junctions permit the passage of molecules that are less than _ Da but restrict the movement of molecules that are greater than _ Da.

1000 Da, 2000 Da Signup and view all the answers

What are the secondary events triggered by the binding of chemical messengers to cell surface receptors?

Modulation of the effector Signup and view all the answers

Which one of these is the equation for a quadratic function?

$f(x) = -4(x + 3)2 + 2$ Signup and view all the answers

Which of the following is NOT one of the four categories of receptors based on their associated mechanisms of signal transduction?

Nuclear receptors Signup and view all the answers

What type of messengers can diffuse across the plasma membrane and interact with cytosolic or nuclear receptors?

Lipophilic messengers Signup and view all the answers

Which of the following is true about adhering junctions?

Adhering junctions are formed by the interactions of intracellular proteins known as catenins. Signup and view all the answers

What is the primary function of gap junctions?

Facilitate the passage of ions and small molecules between adjacent cells. Signup and view all the answers

Which of the following is a characteristic of tight junctions?

Tight junctions create a diffusion barrier between adjacent cells. Signup and view all the answers

What is the function of membrane-associated ligands?

Provide spatial clues in migrating cells. Signup and view all the answers

Which of the following is NOT a mechanism by which cells can directly communicate?

Tight junctions Signup and view all the answers

How are gap junctions regulated?

By changes in cytosolic concentrations of Ca2+, cAMP, H+, and voltage Signup and view all the answers

What is the role of adhering junctions in organ development and remodeling?

They can serve a signaling role. Signup and view all the answers

Study Notes

Cellular Communication Basics

Cellular communication is facilitated by interactions between external signals and specific cell surface receptors.
The binding of messengers to receptors initiates the mobilization of intracellular second-messenger systems.
Hydrophobic messengers, like steroid hormones, can easily cross the plasma membrane and engage cytosolic or nuclear receptors.

Signaling Pathways

Cells utilize various interconnected signaling pathways to meticulously control responses to external stimuli.
Early research in signal transduction was primarily conducted using the nervous system as a model.

Importance of Communication

Cellular communication is vital for a multitude of processes, including embryonic development and physiological responses to environmental changes.
External signals such as odorants, hormones, and neurotransmitters serve as messengers for intercellular communication.

Hormones and Endocrine Function

Hormones are defined as substances produced in one tissue, released into the bloodstream, and transported to target organs to elicit specific responses.
Endocrine glands like the pituitary and thyroid release chemical messengers in response to specific physiological states.

Receptor Mechanisms

Receptors are categorized based on their signaling mechanisms into:
- Ligand-gated ion channels that mediate signaling in electrically excitable cells.
- G protein-coupled receptors that activate/inactivate enzymes or channels indirectly through G proteins.
- Catalytic receptors, which function as enzymes or part of an enzyme complex upon ligand binding.
- Nuclear receptors, which act as transcription factors activated by ligands.

Second Messenger Systems

Second messenger systems amplify received signals and integrate cellular responses.
Upon activation, signals are amplified through second messengers, resulting in widespread effects on downstream targets.
Activation of second messengers can lead to significant increases in cellular concentrations of cyclic adenosine monophosphate (cAMP) within seconds.

Cellular Responses and Control

Control mechanisms ensure that messengers are finely regulated to maintain homeostasis.
The inactivation or degradation of second messengers follows their activation to restore cellular resting states.
Each signaling cascade includes counterbalancing activities that help reset the system post-stimulation.

Intercellular Communication Structures

Gap junctions allow the passage of ions and small molecules (less than 1 kDa) between adjacent cells, modulating their permeability based on various factors.
Adhering junctions form through Ca2+-dependent interactions between cadherin proteins, linking the actin cytoskeleton inside the cells.

Tight Junctions

Composed of transmembrane proteins such as claudins and occludin, tight junctions create barriers between cells while also providing signaling roles.
Proteins like zonula occludens-1 (ZO-1) are key components that stabilize tight junctions.

Membrane-Associated Ligands

Interaction between membrane-associated ligands and receptors facilitates critical communication for processes such as axonal guidance during neural development.

Key Functions of Enzymes and Receptors

Membrane-bound enzymes play crucial roles in signal transduction by facilitating biochemical reactions.
Catalytic receptors are integral to activating enzymatic activities, often instigating cascades of secondary messengers.

Overall Insights

Ligands can initiate distinct cellular responses, demonstrating the nuanced nature of cellular signaling.
Understanding different messenger types and their pathways is fundamental for grasping how cells communicate and respond to their environment.

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"Quiz: Cell Signaling Pathways and Communication Methods" - Test your knowledge on the integration of multiple signaling pathways in cells and the termination of responses through feedback mechanisms. Explore how cells communicate through gap junctions and the coupling of neighboring cells.

Cell Signaling Pathways and Communication Methods Quiz

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Questions and Answers

Cellular communication relies on the interaction between ______ signals and specific cell surface receptors

The mobilization of diffusible intracellular second-messenger systems is a secondary event triggered by the binding of ______ messengers to cell surface receptors

Hydrophobic messengers, such as ______ hormones, can diffuse across the plasma membrane and interact with cytosolic or nuclear receptors

Cells use a number of different, often intersecting ______ signaling pathways to ensure that the cell's response to a stimulus is tightly controlled

Early insight into signal transduction pathways was obtained from studies of the ______ system

Communication among cells is fundamental to all ______ processes, ranging from the induction of embryonic development to the integration of physiological responses in the face of environmental challenges

External signals such as odorants, chemicals that reflect metabolic status, ions, hormones, growth factors, and neurotransmitters can all serve as ______ messengers linking neighboring or distant cells

The classic definition of a hormone is a substance that is produced in one tissue or organ and released into the blood and carried to other organs (targets), where it acts to produce a specific ______.

The idea of endocrine or ductless glands developed from the recogni- tion that certain organs—such as the pituitary, adrenal, and thyroid gland—can synthesize and release specific chemical messengers in response to particular ______ states.

Receptors can be divided into four categories on the basis of their associated mechanisms of signal ______.

Ligand-gated ion channels. Integral membrane pro- teins, these hybrid receptor/channels are involved in sig- naling between electrically excitable ______.

G protein–coupled receptors. These integral plasma membrane proteins work indirectly—through an ______—to activate or to inactivate a separate mem- brane-associated enzyme or channel.

Catalytic receptors. When activated by a ligand, these integral plasma membrane proteins are either enzymes themselves or part of an ______ complex.

Nuclear receptors. These proteins, located in the cytosol or nucleus, are ______-activated transcription factors.

Second-messenger systems amplify signals and integrate responses among cell types. Once a signal has been received at the cell surface, it is typically amplified and transmitted to specific sites within the cells through ______.

For a molecule to function as a ______, its concentration, or window of activity, must be finely regulated.

The cell achieves this control by rapidly producing or activating the ______ messenger and then inactivating or degrading it.

To ensure that the system returns to a resting state when the stimulus is removed, ______ activities function at each step of the cascade.

The involvement of second messengers in catalytic cascades provides numerous opportunities to ______ a signal.

For example, the binding of a ligand to its receptor can generate hundreds of ______ molecules, which can in turn alter the activity of thousands of downstream effectors.

An example of such a cascade is the increased intracellular concentration of the second messenger ______.

Receptor occupancy activates a G protein, which in turn stimulates a membrane-bound enzyme, ______.

This enzyme catalyzes the synthesis of ______ from adenosine triphosphate (ATP), and a 5-fold increase in the intracellular concentration of ______ is achieved in approximately 5 seconds.

This sudden rise in cAMP levels is rapidly counteracted by its breakdown to adenosine 5’-monophosphate by ______.

The permeability of gap junctions can be rapidly regulated by changes in cytosolic concentrations of Ca2+, cAMP, and H+ as well as by the voltage across the cell membrane or membrane potential (Vm). This type of modulation is physiologically important for cell-to-cell _____

Adhering junctions form as the result of the Ca2+-dependent interactions of the extracellular domains of transmembrane proteins called _____

The clustering of cadherins at the site of interaction with an adjacent cell causes secondary clustering of intracellular proteins known as _____, which in turn serve as sites of attachment for the intracellular actin cytoskeleton.

Which one of these is the equation for a line in slope-intercept form?

Which one of these is the equation for a quadratic function?

Which one of these is the equation for an inverse function?

Which one of these is the equation for a square root function?

Which of the following is a characteristic of membrane-bound enzymes?

Which of the following is true about catalytic receptors?

What is the secondary event triggered by the binding of messengers to cell surface receptors?

What is the primary function of catalytic receptors?

What are the integral plasma membrane proteins involved in catalytic receptors?

What triggers the activation of catalytic receptors?

What is the primary function of membrane-bound enzymes?

Which type of messengers can diffuse across the plasma membrane and interact with cytosolic or nuclear receptors?

What do most chemical messengers interact with to trigger a cascade of secondary events?

What type of signaling pathways do cells use to ensure a tightly controlled response to a stimulus?

What type of messengers can serve as chemical messengers linking neighboring or distant cells?

What are the secondary events triggered by the binding of chemical messengers to cell surface receptors?

What type of proteins stabilize tight junctions and have a signaling role?

What type of receptors work indirectly to activate or inactivate a separate membrane-associated enzyme or channel?

Which of the following equations represents a linear function?

Which of the following is the equation of a parabola?

Which of the following equations represents an exponential function?

Which of the following equations represents an inverse function?

Which of the following equations represents a quadratic function?

Which of the following is NOT considered a chemical messenger in cellular communication?

Hydrophobic messengers, such as steroid hormones, can diffuse across the plasma membrane and interact with ______ receptors.

What type of signaling pathways do cells use to ensure a tightly controlled response to a stimulus?

Which of the following equations represents an exponential function?

What is the primary function of membrane-bound enzymes?

Receptors can be divided into four categories on the basis of their associated mechanisms of signal ______.

What is the secondary event triggered by the binding of messengers to cell surface receptors?

Which of the following is NOT one of the four categories of receptors based on their associated mechanisms of signal transduction?

What is the primary function of G protein–coupled receptors?

Which of the following is NOT a step in the signaling events initiated by plasma membrane receptors?

What type of messengers can diffuse across the plasma membrane and interact with cytosolic or nuclear receptors?

What are the secondary events triggered by the binding of chemical messengers to cell surface receptors?

Which of the following is NOT a characteristic of membrane-bound enzymes?

Receptor occupancy activates a G protein, which in turn stimulates a membrane-bound enzyme, ______.

Which of the following is a characteristic of second messengers?

What is the role of second messengers in signal transduction?

Which of the following is an example of a second messenger cascade?

What is the function of G protein in signal transduction?

Which of the following is true about ligands that activate the same signaling pathways in cells?

What is the role of second-messenger systems in a multicellular organism?

What triggers the activation of catalytic receptors?

What is the function of counterbalancing activities in second-messenger systems?

What allows ligands to produce distinct responses in different cells?

Which of the following is true about gap junctions?

What is the function of adhering junctions?

Which of the following is true about tight junctions?

This enzyme catalyzes the synthesis of from adenosine triphosphate (ATP), and a 5-fold increase in the intracellular concentration of is achieved in approximately 5 seconds.

Signal Transduction Pathways & Genomic Effects