Lab 2: Membrane Transport Vocabulary Flashcards

Vocabulary flashcards covering cellular membrane transport mechanisms, passive and active transport, tonicity, and osmosis based on the Lab 2 lecture notes.

Extracellular fluid (ECF)

The environment surrounding the cell.

Intracellular fluid (ICF)

The cytoplasm and organelles located inside the cell.

Passive transport mechanisms

Transport processes in which molecules move from areas of higher concentration to areas of lower concentration without the use of cellular energy ($\text{ATP}$).

Diffusion

The net movement of molecules from an area of higher concentration to an area of lower concentration.

Simple diffusion

The movement of particles from high to low concentration across a membrane without a protein until equilibrium is reached.

Osmosis

The net movement of water molecules from an area of higher concentration to an area of lower concentration through a semi-permeable (or selectively permeable) membrane.

Channel-mediated passive transport

Passive transport in which molecules diffuse through a cell membrane by passing through special openings called membrane channels down their concentration gradient.

Carrier-mediated passive transport

Passive transport in which molecules temporarily bind to a membrane protein that changes shape and moves the molecule across the membrane down its concentration gradient.

Active transport mechanisms

Transport mechanisms requiring cellular energy in the form of $\text{ATP}$ to move molecules against their concentration gradient (from lower to higher concentration) or to move large molecules.

Membrane pump systems

Active transport systems that move molecules against their concentration gradients using $\text{ATP}$ to achieve transport results.

$\text{Na}^+/\text{K}^+$ pump

A membrane pump system that actively pumps $3\,\text{Na}^+$ out of the cell for every $2\,\text{K}^+$ that enters using $\text{ATP}$.

Vesicular transport

A type of membrane transport that moves large molecules into or out of the cell using membrane-bound containers called vesicles.

Endocytosis

A type of vesicular transport where the cell membrane surrounds and engulfs particles, taking them into the cytoplasm.

Pinocytosis

A specific form of endocytosis in which liquid particles are engulfed by the cell membrane.

Phagocytosis

A specific form of endocytosis in which large solid particles or microorganisms are engulfed by the cell membrane.

Exocytosis

A type of vesicular transport in which vesicles fuse with the cell membrane to release large molecules (such as newly formed proteins or neurotransmitters) into the ECF.

Tonicity

The measure of the effective osmotic pressure gradient that determines the direction and extent of water movement across a semi-permeable membrane.

Dialysis membrane

A thin cellophane-like tubing containing tiny pores that allow water molecules to pass through, used as a simple model of a selectively permeable plasma membrane.

Osmotic pressure

The force pulling water toward an area containing solutes such as sugar or salt.

Hypertonic

A description of a solution that contains a higher concentration of solutes compared to another solution.

Hypotonic

A description of a solution that contains a lower concentration of solutes compared to another solution.

Isotonic

A system in which solute concentrations are equal on both sides of a membrane, resulting in no net movement of water and no change in volume.