Cell Membrane and Transport Mechanisms

This set of flashcards covers vocabulary regarding cell membrane structure, passive and active transport mechanisms, and osmotic solutions based on the lecture notes.

Selective permeability

A property of the cell membrane that allows it to control the movement of materials in and out of the cell to maintain homeostasis.

Passive transport

The movement of substances across the cell membrane without energy from an area of high to low concentration; examples include diffusion, osmosis, and facilitated diffusion.

Active transport

The movement of substances across the cell membrane against the concentration gradient (low to high) requiring energy in the form of $ATP$; examples include endocytosis, exocytosis, and protein pumps.

Endocytosis

A process where the cell membrane wraps around a particle to bring it into the cell, such as an amoeba engulfing food or a white blood cell destroying bacteria.

Facilitated diffusion

The movement of molecules from high to low concentration through specific membrane proteins, such as carrier or channel proteins, without using energy.

Membrane proteins

Proteins extending across the cell membrane that assist the cell in communicating and interacting with its surroundings, transport, signaling, and structural support.

Osmosis

The movement of water molecules across a selectively permeable membrane from an area of low solute concentration to high solute concentration until concentrations are equal.

Hypertonic solution

A solution where the concentration of solutes outside the cell is higher than inside, causing water to move out of the cell and making it shrink or shrivel.

Hypotonic solution

A solution where the concentration of solutes outside the cell is lower than inside, causing water to move into the cell and making it swell or burst.

Isotonic solution

A solution where the concentrations are equal on both sides of the membrane, resulting in no net movement of water while the cell stays the same size.

Hydrophilic head

The part of the phospholipid bilayer that is water loving.

Hydrophobic tail

The part of the phospholipid bilayer that is water fearing.

Carbohydrates

Molecules in the cell membrane that allow for cell recognition.

Cholesterol

A component of the cell membrane that keeps the membrane flexible.

Sodium-potassium pump

A type of active transport that requires $ATP$ to move sodium ions out of the cell and potassium ions into the cell against their concentration gradients.

Diffusion

The process by which small, nonpolar gases like oxygen ($O_2$) and carbon dioxide ($CO_2$) move across the cell membrane until equilibrium is reached.

Exocytosis

The process of getting rid of cell waste by discharging it from sacs at the cell surface.

Dynamic equilibrium

A state where solute and solvent are evenly distributed and molecules continue to move across the membrane in both directions, but there is no net movement.

Carrier and channel proteins

Specialized proteins required to help move large molecules like glucose across the membrane during facilitated diffusion.