Simple and Facilitated Diffusion Guided Notes - DIGITAL

Selectively Permeable

Refers to the ability of the phospholipid bilayer to allow certain molecules to pass through while blocking others.

Permeable Molecule Types

Order of permeability: 1. Small, nonpolar molecules 2. Mostly permeable: small, uncharged polar molecules 3. Mostly impermeable: large, uncharged polar molecules 4. Impermeable: ions and polar molecules with a charge.

Transmembrane Integral Protein

Proteins that span the width of the phospholipid bilayer and aid in the transport of materials across the membrane.

Amphipathic

Describes integral proteins that have both hydrophobic and hydrophilic regions.

Concentration Gradient

A difference in concentration of a substance across a space, visualized like a hill with a bigger gradient representing a steeper hill.

Down the Concentration Gradient

Movement from an area of high concentration to an area of low concentration.

Active Transport

Transport that requires an additional input of energy (ATP) to move substances against their concentration gradient.

Passive Transport

Transport that does not require an additional input of energy (ATP), moving substances down their concentration gradient.

Types of Passive Transport

Includes simple diffusion, facilitated diffusion, and osmosis.

Types of Active Transport

Includes pump proteins and bulk transport methods like exocytosis and endocytosis.

Diffusion

The movement of a substance down a concentration gradient, powered by existing molecular movement.

Factors Affecting Diffusion Rate

Includes concentration gradient, distance, temperature, size of molecules, and polarity.

Dynamic Equilibrium

A state of constant movement in equal amounts and opposite directions, resulting in equal concentration on both sides of a membrane.

Simple Diffusion

The movement of a substance down a concentration gradient across a phospholipid bilayer without requiring energy.

Facilitated Diffusion

The movement of molecules down a concentration gradient with the assistance of transport proteins, requiring no energy input.

Transmembrane Integral Protein in Facilitated Diffusion

Required to assist in the movement of molecules across the membrane.

Channel Proteins

Transmembrane proteins that allow specific molecules or ions to pass through the membrane by opening and closing.

Carrier Proteins

Transmembrane proteins that undergo conformational changes to transport molecules from one side of the membrane to the other.

Ligand-gated Channels

Channel proteins that open or close in response to a molecule (ligand) binding.

Voltage-gated Channels

Channel proteins that open or close in response to changes in electrical charge across the membrane.