Cellular Communication Mechanisms Quiz

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What is the role of potassium in determining the resting membrane potential?

It is not involved in establishing the resting membrane potential.

It plays a significant role in maintaining the resting membrane potential. (correct)

It has a negligible effect on the resting membrane potential.

It contributes equally with calcium to the resting membrane potential.

Why is the resting membrane potential closest to the equilibrium potential for potassium (EK = -90 mV)?

Potassium leak channels allow potassium efflux at rest. (correct)

Potassium has the highest concentration inside the cell.

The cell membrane is impermeable to potassium.

Potassium has a high equilibrium potential compared to other ions.

Which ions have equilibrium potentials far from the resting membrane potential?

Potassium and chloride

Sodium and calcium (correct)

Sodium and potassium

Calcium and chloride

What does the Goldman-Hodgkin-Katz (GHK) equation determine?

The membrane permeability to specific ions Signup and view all the answers

Which cells have a resting membrane potential of around -70 mV?

Sensory neurons Signup and view all the answers

How do sodium leak channels affect the resting membrane potential?

They allow a small influx of sodium ions, helping maintain RMP. Signup and view all the answers

What are the ions relevant for understanding the cell's electrical properties and action potential?

K+, Na+, Ca2+, Cl– Signup and view all the answers

What do ions need in order to move across the cell membrane?

Pathways provided by ion channels Signup and view all the answers

What determines the net flux of an ion through the membrane, as per the text?

Concentration gradient, membrane potential, ion membrane conductance Signup and view all the answers

In Ohm's law equation (IX = gX(Vm - EX)), what does (Vm - EX) represent?

Driving force for the movement of ion X+ Signup and view all the answers

What happens when there is an inward current across the cell membrane?

There is an influx of positive charges Signup and view all the answers

What is the role of gX in determining the net flux of an ion according to Ohm's law?

Membrane conductance specific for X+ Signup and view all the answers

What determines the receptor a ligand binds to?

Chemical nature of the ligand Signup and view all the answers

How do ligands affect receptor affinity for inhibitory proteins?

Decrease receptor affinity Signup and view all the answers

Intracellular receptors modify cell behavior through changes in:

Gene expression Signup and view all the answers

Which subunit of G proteins determines receptor coupling to signaling modules?

Alpha subunit Signup and view all the answers

What type of signaling involves the activation of membrane-bound adenylyl cyclases and synthesis of cAMP?

Gs-coupled signaling pathway Signup and view all the answers

Which ligand-binding modulates signal transduction pathways?

Selectivity Signup and view all the answers

Which type of communication allows the transfer of small molecules and electrical signals from cell to cell?

Gap junctions Signup and view all the answers

What defines autocrine signaling?

Chemical signal acts on the same cell that released it Signup and view all the answers

Which mode of cell communication uses hormones released into the blood to act on specific receptors in the body?

Endocrine system Signup and view all the answers

What plays an important role in the conduction of action potentials of cardiac muscle?

Gap junctions Signup and view all the answers

Which signaling occurs when a chemical signal is released and acts on neighboring cells near the site of release?

Paracrine signaling Signup and view all the answers

Which term describes the situation where all binding sites for a specific ligand have been occupied?

Saturation Signup and view all the answers

In what way does the nervous system communicate with cells and specific cell receptors?

Using both chemical signals and electrical signals Signup and view all the answers

What type of ligands bind to the receptor and prevent any response from occurring?

Antagonists Signup and view all the answers

What occurs when a high concentration of a signaling molecule results in a decrease in the number of receptors in the membrane?

Down-regulation Signup and view all the answers

Which process involves a chemical modulator binding to a receptor, blocking its activation by the ligand?

Receptor desensitization Signup and view all the answers

What is the term used for ligands that bind to and activate receptors, causing a response?

Agonists Signup and view all the answers

In what situation does up-regulation of receptors typically occur?

Low ligand levels Signup and view all the answers