Cell Membrane Transport Quiz

<p>Voltage-gated channels (A)</p> Signup and view all the answers

<p>Active transport pumps such as the $Na^+-K^+$ ATPase pump (D)</p> Signup and view all the answers

<p>The diffusion coefficient, reflecting the solute particle size and the viscosity of the solution. (A)</p> Signup and view all the answers

<p>The flux (J) will decrease. (A)</p> Signup and view all the answers

<p>The point at which all binding sites are occupied. (C)</p> Signup and view all the answers

<p>The rate of diffusion increases. (B)</p> Signup and view all the answers

<p>Stereospecificity. (B)</p> Signup and view all the answers

<p>The rate of transport increases steeply. (A)</p> Signup and view all the answers

<p>Glucose transport will remain unaffected. (D)</p> Signup and view all the answers

<p>∆C (C)</p> Signup and view all the answers

<p>Urea is an ineffective osmole because it freely crosses the membrane, rapidly equilibrating. (D)</p> Signup and view all the answers

<p>The concentration of impermeant solutes. (B)</p> Signup and view all the answers

<p>Hypertonic, causing the cell to shrink. (A)</p> Signup and view all the answers

<p>Primary active transport (D)</p> Signup and view all the answers

<p>24 mV (A)</p> Signup and view all the answers

<p>It involves a protein carrier or channel. (C)</p> Signup and view all the answers

<p>Leakage of potassium ions out of the cell via K2P channels. (A)</p> Signup and view all the answers

<p>The electrochemical gradient. (D)</p> Signup and view all the answers

<p>The Em moves toward the equilibrium potential of the most permeable ion. (B)</p> Signup and view all the answers

<p>The electrochemical gradient set up by primary active transport. (C)</p> Signup and view all the answers

<p>Electrochemical equilibrium (A)</p> Signup and view all the answers

<p>Bulk transport (endocytosis). (A)</p> Signup and view all the answers

<p>It normally has no effect on the concentrations. (B)</p> Signup and view all the answers

<p>Ligand-gated ion channels (A)</p> Signup and view all the answers

<p>DAG and IP3 (A)</p> Signup and view all the answers

<p>Nuclear receptors (C)</p> Signup and view all the answers

<p>Atrial Natriuretic Peptide (ANP) (B)</p> Signup and view all the answers

<p>Suppression of enzymatic activity (D)</p> Signup and view all the answers

<p>It always looks identical, depolarizes to the same potential, and repolarizes to the same resting potential. (B)</p> Signup and view all the answers

<p>It is propagated down the axon without decrement, being continuously regenerated. (C)</p> Signup and view all the answers

<p>Only a stimulus over a specific threshold can produce an action potential. (B)</p> Signup and view all the answers

<p>The inactivation gates of the sodium channels are closed. (A)</p> Signup and view all the answers

<p>Another action potential can be elicited only with a larger-than-normal stimulus. (A)</p> Signup and view all the answers

<p>By spreading from active regions to adjacent inactive regions, depolarizing the membrane. (A)</p> Signup and view all the answers

<p>At the initial segment of the axon (axon hillock). (B)</p> Signup and view all the answers

<p>Membrane resistance, internal resistance and capacitance. (A)</p> Signup and view all the answers

The membrane potential at which the chemical gradient driving an ion across the membrane is exactly balanced by the electrical gradient.

The difference between the resting membrane potential (RMP) and the equilibrium potential for a specific ion.

The cell membrane allows some ions to pass through more easily than others.

The overall membrane potential is influenced by the equilibrium potential of the most permeable ion.

The movement of potassium ions (K+) out of the cell due to the concentration gradient creates a negative charge inside the cell.

The ability of a channel to allow ions to flow through it. It depends on the probability that the channel is open. A higher probability of being open means higher conductance or permeability.

The amount of substance that passes through a unit area per unit time.

The coefficient that describes the ease with which a substance can move through a membrane.

These channels open and close in response to changes in voltage across the membrane.

These channels are activated by specific molecules binding to them, such as hormones or neurotransmitters.

The ratio of a substance's concentration in the membrane to its concentration in the surrounding solution.

These channels respond to changes in internal signaling molecules, like cAMP or calcium.

The rate at which a substance diffuses through a solution.

These channels are activated by mechanical forces, like stretching or pressure on the membrane.

The thickness of the membrane through which diffusion occurs.

The difference in concentration of a substance between two compartments.

The point at which all binding sites on carrier proteins are occupied, resulting in a plateau in transport rate.

The specific ability of carrier proteins to bind and transport only certain molecules, usually with specific shapes or structures.

Urea is a molecule that can freely cross cell membranes, meaning it doesn't contribute to osmotic pressure changes.

The osmotic pressure of a solution is determined by the concentration of solutes that cannot cross the cell membrane (impermeable solutes), as these solutes create an uneven water distribution.

Isotonic solutions have the same concentration of impermeable solutes as the cell, resulting in no change in cell volume.

Hypotonic solutions have a lower concentration of impermeable solutes than the cell, causing water to move into the cell and potentially cause it to swell or burst.

Hypertonic solutions have a higher concentration of impermeable solutes than the cell, causing water to move out of the cell and potentially cause it to shrink.

Simple diffusion is the movement of molecules across a membrane from a region of high concentration to a region of low concentration, without the help of any membrane proteins. This process is passive and follows the concentration gradient.

Facilitated diffusion uses a membrane protein to help molecules move across the membrane, following the concentration gradient. This process is also passive.

Active transport uses energy (ATP) to move molecules across a membrane against their concentration gradient, from a region of low concentration to a region of high concentration.

Receptor class that directly changes membrane permeability by opening or closing ion channels. Examples include GABA, acetylcholine (muscle), ATP, glutamate, and NMDA receptors.

Receptor class that uses G proteins to activate intracellular signaling pathways. Examples include acetylcholine, peptides, cytokines, odorants, and lipids.

A signaling molecule that binds to a receptor and initiates a cellular response. Examples include neurotransmitters, hormones, and growth factors.

A signaling molecule produced inside the cell in response to the first messenger. Examples include cAMP, DAG, IP3, and Ca++. They amplify the signal and influence downstream events.

A signaling pathway that involves receptor tyrosine kinases (RTKs) and leads to phosphorylation of intracellular proteins. Examples include insulin, EGF, and erythropoietin receptors.

All action potentials for a given cell look identical, reach the same peak potential during depolarization, and return to the same resting potential after repolarization.

The action potential travels down the entire length of the axon without losing its size or shape. This is because the action potential is regenerated as it moves along the axon.

An action potential can only be generated if the stimulus reaches a certain threshold level. Stimuli below this threshold will not trigger an action potential.

This period occurs immediately after an action potential and prevents another action potential from being generated, no matter how strong the stimulus. It is caused by the inactivation of sodium channels during depolarization.

This period follows the absolute refractory period. During this time, a stronger than usual stimulus is required to generate an action potential. This is due to the increased potassium conductance, making it harder for the membrane to depolarize.

The speed at which an action potential travels along a nerve fiber is called conduction velocity. It is determined by factors like the diameter of the axon, the presence of myelination, and the temperature.

The resistance of the membrane to the flow of ions. A higher membrane resistance means less current leaks out of the axon, allowing the signal to travel further.

The resistance of the cytoplasm to the flow of ions. A lower internal resistance allows for faster conduction.