Chapter 12: Transport Across Cell Membranes

Flashcards covering essential vocabulary and concepts related to transport across cell membranes, utilizing key terms and their definitions.

Diffusion

The spread of molecules from high concentration to low concentration.

Osmosis

The diffusion of water across a selectively permeable membrane.

Active Transport

Transport of molecules against their concentration gradient, requiring energy.

Passive Transport

Transport of molecules along their concentration gradient without the use of energy.

Channel Proteins

Proteins that create passageways in the membrane for specific molecules to cross.

Transporters

Proteins that bind specific molecules and undergo conformational changes to transport them.

Aquaporins

Channel proteins that facilitate the transport of water across cell membranes.

Membrane Potential

The voltage difference across a cell membrane.

Resting Membrane Potential

The membrane potential of a cell at rest, typically around -70 mV for neurons.

Electrochemical Gradient

The combined effect of concentration gradients and membrane potential on ion movement.

Sodium-Potassium Pump

An active transport mechanism that pumps 3 Na+ ions out and 2 K+ ions into the cell.

Ligand-Gated Channels

Channels that open or close in response to the binding of a ligand.

Voltage-Gated Channels

Channels that open or close in response to changes in membrane potential.

Chemical Gradient

The difference in the concentration of a substance across a space.

Hydrophobic Molecules

Molecules that repel water and can diffuse freely across cell membranes.

Polar Molecules

Molecules that have a partial charge and generally cannot diffuse freely across the lipid bilayer.

Ion Channels

Proteins that facilitate the passive movement of ions across a membrane.

Resting state of Na+ Channels

In their closed state but can open in response to a threshold potential.

Depolarization

A decrease in membrane potential, making the inside of the cell more positive.

Repolarization

The process of restoring the membrane potential to its resting level after depolarization.

Hyperpolarization

An increase in membrane potential, making the inside of the cell more negative.

Threshold Potential

The critical level of depolarization that must be reached for an action potential to occur.

Symporter

A transporter that moves two different molecules in the same direction across the membrane.

Antiporter

A transporter that moves two different molecules in opposite directions across the membrane.

Mechanically Gated Channels

Channels that open in response to physical stimuli such as pressure.

pH Regulation

The mechanisms cells use to maintain their internal pH.

Calcium Pump

An ATP-driven pump that moves Ca2+ ions out of the cell or into organelles.

Glucose Transporter

Transport proteins that facilitate the movement of glucose across cell membranes.

Nernst Equation

An equation used to calculate the equilibrium potential for a particular ion across a membrane.

Concentration Gradients

Differences in concentration of a substance across distances, influencing diffusion.

Facilitated Diffusion

Passive transport of molecules across a membrane via proteins without energy.

Selectively Permeable

A property of cell membranes that allows certain molecules to pass while blocking others.

Hydrophilic Molecules

Molecules that are attracted to water and often do not cross the lipid bilayer easily.

Neurotransmitters

Chemicals released by neurons to transmit signals to other cells.

Synaptic Vesicles

Small membrane-bound structures that store neurotransmitters.

Action Potential

A rapid rise and fall in membrane potential, triggering a signal in neurons.

Gated Ion Channels

Channels that can open or close in response to specific signals.

Chemical Synapse

A junction where neurotransmitters are released to transmit nerve signals.

Neuronal Communication

The process of transmitting signals within and between neurons.

Cation Channels

Ion channels that allow positively charged ions to pass through the membrane.

Anion Channels

Ion channels that allow negatively charged ions to pass through the membrane.

Na+ Gradient

The difference in sodium ion concentration across the membrane, maintained by the Na+/K+ pump.

K+ Gradient

The difference in potassium ion concentration across the membrane.

Aquaporin Conformation

The arrangement of aquaporin proteins that determines their ability to transport water.

Glucose-Na+ Symporter

A transport mechanism that utilizes the Na+ gradient to facilitate glucose uptake.

Resting State of Cells

The state of a cell when it is not depolarized and maintains a membrane potential.

Patch-Clamp Technique

A method used to study ion channels by isolating a small patch of membrane.

Transmembrane Protein

A type of membrane protein that spans the entire lipid bilayer.

Hydration Shell

The layer of water molecules that surrounds ions or polar molecules.

Ion Selectivity

The ability of ion channels to allow only certain ions to pass through.

Chemical Gradient Tracking

The process of measuring how concentration differences affect transport.

Signal Transduction

The process by which a cell responds to signals through receptor binding.

Glucose Uptake Mechanism

The pathways and transporters that cells use to absorb glucose.

Endocytosis

The process of engulfing substances into a cell via the membrane.

Exocytosis

The process of vesicles fusing with the plasma membrane to release substances outside the cell.

Membrane Fluidity

The viscosity of the lipid bilayer, affecting the movement and function of proteins.

Cellular Integrity

The maintenance of cell structure and function through membrane dynamics.

Electrogenic Pumps

Active transport pumps that create a charge differential across the membrane.

Neuronal Resting Potential Determinants

Factors that establish and maintain resting membrane potential.

Bacterial Growth Regulatory Mechanism

The processes used by bacteria to thrive, often involving transport proteins.

Hormonal Regulation of Transport

The influence of hormones on transport mechanisms in cells.

Glucose Transport Alteration Mechanism

Factors that influence the capacity for glucose transport in cells.

Transport Protein Specificity

The ability of transport proteins to discriminate between different molecules.

Ligand Activation of Ion Channels

The process by which neurotransmitters trigger ion channel opening.

Potassium Channel Characteristics

The properties specific to potassium channels, including selectivity and gating.

Voltage Gates in Neuronal Action

The role of voltage-gated channels in generating and propagating action potentials.

Ion Exchange Mechanism

The process of ions being exchanged across membranes via transporters.

Maintenance of Osmotic Balance

The processes that ensure cells maintain the proper balance of water and solutes.

Homeostatic Regulation Across Membranes

The mechanisms that regulate stable internal conditions in response to external changes.

Neuronal Synapse Functionality

The effectiveness of synapses in transferring signals between neurons.

Chemical Sensor Mechanism

The processes by which cells detect chemical signals from the environment.

Action Potential Propagation

The transmission of electrical signals along the axon of a neuron.

Electrical Synapse Characteristics

A type of synapse that allows direct electrical communication between neurons.

Facilitated Transport Mechanisms

Transport processes that assist in the movement of substances across membranes.

Genetic Control of Ion Channel Expression

How gene expression regulates the formation of ion channels.

Ion Channel Dysfunction Effects

Consequences of malfunctioning ion channels on cellular and physiological processes.

Neuroactive Substance Role

The function of various substances in influencing neural activity.

Neurotransmitter Release Mechanisms

Processes involved in the release of neurotransmitters at synapses.

Calcium's Role in Neurotransmitter Release

How calcium influx triggers the release of neurotransmitters from synaptic vesicles.

Homeostatic Mechanisms in Neuroscience

Regulatory processes that maintain stability in the nervous system.

Hodgkin-Huxley Model

A theory that describes how action potentials in neurons are initiated and propagated.

Ion Fluctuations in Neuronal Activity

Variations in ion concentrations that affect neuronal signaling.

Neural Transmission Types

The different methods through which nerve signals can be communicated.

Mechanisms of Pain Transmission

How signals of pain are relayed through the nervous system.

Mechanisms of Neurotransmitter Action

The pathways through which neurotransmitters exert their effects on target cells.

Role of Na+ in Neural Activity

The function of sodium ions in generating action potentials.

Role of K+ in Neuronal Resting State

The significance of potassium ions in maintaining resting membrane potential.

Neuronal Response to Stimuli

How neurons react to various stimuli based on their membrane potential.

Role of Calcium in Cell Signaling

The importance of calcium ions in mediating signal transduction within cells.

Neurotransmitter Diversity

The variety of neurotransmitters and their functions in the nervous system.

Pathways of Ion Channel Regulation

The mechanisms that control the activity and function of ion channels.

Neuronal Development Factors

Influences on the growth and development of the nervous system.

Neuronal Structure and Function Connection

The relationship between the structure of neurons and their functional capabilities.

Synaptic Plasticity Mechanisms

The processes that enable the strengthening or weakening of synapses.

Ion Channel Behavior During Anoxia

How ion channels respond to conditions of low oxygen availability.

Influence of Environmental Factors on Neurons

How external factors affect neuronal health and activity.

Ethical Considerations in Neuroscience Research

The moral implications of conducting research in neuroscience.

Research Techniques in Neurobiology

Methodologies used in studying neural systems.

Transgenic Models in Neuroscience

Genetically modified organisms used to study neuronal functions.