Cell Biology and Membrane Transport Vocabulary

Flashcards covering cell structure, cell membrane composition, membrane proteins, passive transport, active transport, and vesicle transport mechanisms from Anatomy and Physiology.

Cell

The basic unit of life, responsible for molecule synthesis, communication, cell metabolism and energy release, and reproduction and inheritance through DNA.

Phospholipids

Amphipathic molecules composed of hydrophilic phosphate heads and hydrophobic fatty acid tails that form the major structural component of the cell membrane bilayer.

Hydrophilic Head

The polar region of a phospholipid molecule containing a phosphate group and glycerol that is attracted to water.

Hydrophobic Tails

The nonpolar region of a phospholipid molecule containing saturated and unsaturated fatty acids that is repelled by water.

Intracellular Fluid (ICF)

The fluid located inside the cell, which is also called cytosol.

Extracellular Fluid (ECF)

The fluid located outside of the cell.

Transmembrane Proteins

Integral membrane proteins that span the entire width of the cell membrane.

Peripheral Proteins

Proteins that do not span the cell membrane, but are attached to either its interior or exterior surface.

Glycoproteins

Proteins with carbohydrate molecules attached that aid in cell-cell recognition.

Glycocalyx

A structure formed by numerous glycoproteins in some cells that can function as hormone receptors, facilitate binding to other cells, and help break down nutrients.

Passive Transport

Movement of molecules across a membrane that does not require energy and depends on a concentration gradient.

Simple Diffusion

A type of passive transport where small, nonpolar molecules move from higher to lower concentration directly through the membrane without using proteins.

Facilitated Diffusion

A type of passive transport where molecules, such as polar or ionic molecules, move down their concentration gradient with the assistance of transmembrane proteins.

Osmosis

The movement of water across a semipermeable membrane from an area of lower solute concentration (higher water concentration) to an area of higher solute concentration (lower water concentration).

Isosmotic Solutions

Solutions that have equal concentrations of solute.

Hyperosmotic Solution

A solution that contains more solute when compared to another solution.

Hypoosmotic Solution

A solution that contains less solute when compared to another solution.

Tonicity

A property describing the osmolarity of the extracellular fluid (ECF) compared to the cytosol of the cell.

Isotonic Solution

A solution that has an equal water concentration across the cell membrane, allowing the cell to function normally.

Hypertonic Solution

A solution containing more solutes in the external environment, which causes water to leave the cell and the cell to shrink.

Hypotonic Solution

A solution containing fewer solutes in the external environment, which causes water to enter the cell, making it swell and potentially burst.

Active Transport

Movement of molecules across a cell membrane against their concentration gradient (from lower to higher concentration) requiring energy.

Primary Active Transport

A type of active transport that directly utilizes ATP as its energy source.

Secondary Active Transport

A type of active transport that utilizes an electrochemical gradient as its energy source.

Symporters

Transport proteins that move two molecules in the same direction across the cell membrane.

Antiporters

Transport proteins that move two molecules in opposite directions across the cell membrane.

Sodium-Potassium Pump

A primary active transport protein that uses ATP to move $3$ sodium ions out of the cell and $2$ potassium ions into the cell against their concentration gradients.

Endocytosis

A form of active transport in which the cell membrane engulfs materials and pinches off to form a vesicle inside the cell.

Phagocytosis

A form of endocytosis where the cell membrane extends outward to engulf large particles or molecules.

Pinocytosis

A form of endocytosis involving membrane invagination to bring in small amounts of fluid containing dissolved substances.

Receptor-Mediated Endocytosis

A selective form of endocytosis where a specific ligand binds to a membrane receptor to initiate cellular entry.

Exocytosis

An active transport process of cell secretion or exporting material, where a vesicle fuses with the cell membrane to release its contents outside the cell.