POB Lesson 6 Vocab

Phospholipid

macromolecule that is nonpolar and insoluble in water

Glycocalyx

The carbohydrates on the cell’s exterior surface

Amphipathic

A molecule that has a hydrophobic and hydrophilic part (ex. lipids)

Saturated

long-chain hydrocarbon with single covalent bonds in the carbon chain; the number of hydrogen atoms attached to the carbon skeleton is maximized

Unsaturated

long-chain hydrocarbon that has one or more double bonds in the hydrocarbon chain

Phospholipid bilayer

A membrane made out of phospholipids, where the hydrophilic head groups face the aqueous solution while the hydrophobic tails stay in the middle of the bilayer

Selective permeability

membrane characteristics that allows some substances through

Fluid-mosaic model

describes the plasma membrane's structure as a mosaic of components including phospholipids, cholesterol, proteins, glycoproteins, and glycolipids (sugar chains attached to proteins or lipids, respectively), resulting in a fluid character (fluidity)

Cholesterol

The most common steroid; helps keep membrane stable, flexible, fluid across different temperatures

Glycolipid

combination of carbohydrates and lipids

Glycoprotein

combination of carbohydrates and proteins

Integral membrane protein

protein integrated into the membrane structure that interacts extensively with the membrane lipids' hydrocarbon chains and often spans the membrane

Transmembrane protein

A type of integral membrane protein that spans the entirety of the cell membrane; many facilitate the movement of molecules and ions across the membrane

Transmembrane domain

Hydrophobic membrane-spanning region part of a cell-surface receptor

Lipid-anchored protein

Proteins covalently attached to lipids embedded into biological membranes

Peripheral membrane protein

Type of protein that attaches temporarily to the surface of a biological membrane or to other membrane proteins without embedding into the hydrophobic core of the lipid bilayer

Receptor proteins

A specialized protein that binds to specific chemical signals to start a response inside a cell

Cell identity marker

Specific molecule, usually protein, glycoprotein, or carbohydrate, that characterizes or “marks” a cell

Enzymes

catalyst in a biochemical reaction that is usually a complex or conjugated protein

Cell adhesion protein

surface proteins that help cells stick to other cells or to the extracellular matrix

Cytoskeletal attachment protein

a specialized molecule that links a cell’s internal protein fibers to cell membranes, organelles, or other cells

Transport protein

A specialized protein embedded in a cell membrane that helps move ions, small molecules, and nutrients into and out of the cell

Channel protein

A special type of transmembrane protein that forms an open, water-filled pore through a cell membrane to let specific polar molecules and ions pass

Ion channel

pore-forming proteins in cell membranes that allow charged ions to pass through passively

Passive transport

The movement of substances across a cell membrane from an area of high concentration to an area of low concentration without using cellular energy

Carrier protein

a specialized cell membrane protein that moves specific molecules or ions across a cell membrane by binding to them and changing its shape

Facilitated diffusion

a type of passive transport where molecules move across a cell membrane from an area of higher concentration to an area of lower concentration with the help of specialized proteins

Active transport

the movement of molecules or ions across a cell membrane from a region of lower concentration to a region of higher concentration

Na+K+ATPase

A type of “pump” that carries sodium and potassium ions; also known as an antiporter carrier protein

Antiporter

transporter that carries two ions or small molecules in different directions

Symporter

transporter that carries two different ions or small molecules, both in the same direction

Osmosis

transport of water through a semipermeable membrane according to the water's concentration gradient across the membrane that results from the presence of solute that cannot pass through the membrane

Isotonic

situation in which the extracellular fluid has the same osmolarity as the fluid inside the cell, resulting in no net water movement into or out of the cell

Hypertonic

situation in which extracellular fluid has a higher osmolarity than the fluid inside the cell, resulting in water moving out of the cell

Hypotonic

situation in which extracellular fluid has a lower osmolarity than the fluid inside the cell, resulting in water moving into the cell

Endocytosis

type of active transport that moves substances, including fluids and particles, into a cell

Pinocytosis

a variation of endocytosis that imports macromolecules that the cell needs from the extracellular fluid

Receptor-mediated endocytosis

variation of endocytosis that involves using specific binding proteins in the plasma membrane for specific molecules or particles, and clathrin-coated pits that become clathrin-coated vesicles

Target protein

a specific protein molecule that a drug, hormone, or other chemical messenger binds to in order to produce a cellular or therapeutic effect

Clathrin

protein that coats the plasma membrane's inward-facing surface and assists in forming specialized structures, like coated pits, for phagocytosis

Phagocytosis

The process by which a cell takes in large particles, such as other cells or relatively large particles