Cell Biology Membrane Transport and Cytoskeleton Vocabulary

Vocabulary flashcards covering cell membrane transport mechanisms, diffusion, osmosis, osmolarity, tonicity, and cytoskeletal components based on lecture notes.

Cytoskeleton

A series of rods in the cytoplasm that support cell structures and generate cellular movements.

Microfilaments

The thinnest cytoskeletal rods made of actin protein, arranged in meshes or bundles, which brace and strengthen the cell surface and assist in cell shape changes and movements.

Microtubules

Long, slender tubes made of globular tubulin protein radiating from the centrosome, determining cell shape and acting as railroad tracks to move organelles.

Intermediate Filaments

The most stable and permanent cytoskeletal elements with intermediate diameter that form guy wires with high tensile strength to resist pulling forces on cells.

Inclusions

Lifeless chemical substances, such as stored nutrients and pigments, that usually stay in the cell temporarily.

Interstitial Fluid

Also known as extracellular fluid, the fluid bathing body cells that contains amino acids, sugars, fatty acids, vitamins, hormones, neurotransmitters, salts, and waste products.

Passive Transport

Cellular transport processes that require no energy ($\text{ATP}$) to move substances across the cell membrane, including diffusion, facilitated diffusion, osmosis, and filtration.

Active Transport

Cellular transport processes that require physiological energy ($\text{ATP}$) to move substances across the cell membrane, including active transport, endocytosis, and exocytosis.

Diffusion

The spontaneous movement of molecules or ions down a concentration gradient from regions of higher concentration toward regions of lower concentration.

Equilibrium

The state reached when molecules are evenly mixed in a solution and concentrations remain constant, while molecular motion continues.

Simple Diffusion

The diffusion of solutes (particles dissolved in water) through a differentially permeable membrane.

Lipid-Soluble Membrane Transport

The transport pathway where lipid-soluble and nonpolar substances, such as $O_2$, $CO_2$, fat-soluble vitamins, and alcohol, pass through the cell membrane by diffusion.

Pore Transport

The transport pathway where small, lipid-insoluble substances, such as water and small ions ($Na^+$ and $K^+$), pass through the cell membrane via pores.

Facilitated Diffusion

A passive process in which specific protein carrier molecules carry molecules, such as lipid-insoluble high-molecular-weight sugars, across a membrane from high to low concentration.

Insulin

A hormone that promotes the facilitated diffusion of glucose through some cell membranes.

Carrier Molecule Conformational Model

The model explaining facilitated diffusion, where a carrier protein spanning the membrane binds a specific molecule, changes shape (conformation), and expels it on the opposite side.

Osmosis

The diffusion of water through a differentially permeable membrane from a region of higher water concentration to a region of lower water concentration.

Osmolarity

The total concentration of all solute particles in a solution.

Osmotic Pressure

The pressure needed to stop osmosis due to the concentration of non-diffusible solute particles, which increases as osmolarity increases.

Tonicity

The ability of a solution to change the tone or shape of cells by altering its internal water volume, derived from ton meaning tension.