Comparative Feedback Loops and Membrane Transport

Flashcards covering key concepts from lectures on feedback loops and membrane transport mechanisms.

Negative Feedback Loop

Opposes change and maintains homeostasis by reducing output.

Positive Feedback Loop

Amplifies change and moves further away from the original state, typically requiring an external factor to stop the process.

Membrane Transport Proteins

Proteins that facilitate the movement of ions and molecules across biological membranes.

Channel Proteins

Membrane transport proteins that form open paths for ions and molecules, allowing passive transport.

Cotransporter

A transport protein that moves multiple molecules/ions across a membrane; can be a symporter or antiporter.

Pump

A transport mechanism that requires energy, typically from ATP hydrolysis, to move ions against their concentration gradient.

Leak Channel

A type of channel that is always open, allowing ions to pass in and out of the cell freely.

Equilibrium Potential

The membrane potential at which the concentration gradient for a given ion is balanced by the electrical gradient.

Nernst Equation

A formula used to calculate the equilibrium potential for an ion based on its concentration inside and outside the cell.

Resting Membrane Potential

The electrical potential difference across the plasma membrane of a cell at rest, primarily influenced by ion concentrations.

Goldman Equation (GHK Equation)

An equation used to calculate the membrane potential considering multiple ions, weighted by their permeability.