Ch. 7: Membrane Structure and Function - Review

Amphipathic

Molecules that have both hydrophilic (water-attracting) and hydrophobic (water-repelling) regions.

Semi-permeable

A property of membranes that allows selective passage of substances, letting some through while restricting others.

Crenation

The process where animal cells shrink due to loss of water in a hypertonic solution.

Turgid

A state in which plant cells are swollen and firm due to water intake, typically in a hypotonic solution.

Lysis

The breaking down or destruction of a cell, often occurring when a cell is in a hypotonic solution.

Plasmolysis

The process in which a plant cell loses water in a hypertonic solution, causing the cell membrane to pull away from the cell wall.

Fluid-mosaic model

A model that describes the structure of cellular membranes as a mosaic of various components that provides fluidity and flexibility.

Phospholipids

Molecules that form the bilayer of the plasma membrane, consisting of hydrophilic heads and hydrophobic tails.

Membrane proteins

Proteins that reside in or on the plasma membrane, contributing to various functions, such as transport and signaling.

Glycolipids

Lipids with carbohydrate chains attached that play roles in cell recognition and signaling.

Glycoproteins

Proteins with carbohydrate chains that are involved in cell recognition, signaling, and immune responses.

Cholesterol

A lipid that helps maintain membrane fluidity and stability by preventing fatty acid chains from packing too tightly.

Concentration gradient

The difference in concentration of a substance across a space, affecting diffusion rates.

Charge gradient

The difference in charge across a membrane, which can influence the movement of ions.

Electrochemical gradient

The combined difference in concentration and charge across a membrane that drives ion movement.

Facilitated diffusion

A type of passive transport that uses specific proteins to help molecules diffuse across the membrane.

Osmosis

The diffusion of water across a semi-permeable membrane from a region of lower solute concentration to a higher solute concentration.

Hypertonic solution

A solution that has a higher concentration of solutes outside the cell than inside, leading to crenation in animal cells.

Hypotonic solution

A solution that has a lower concentration of solutes outside the cell than inside, leading to turgidity or lysis.

Isotonic solution

A solution that has equal concentrations of solutes inside and outside the cell, resulting in no net movement of water.

Active transport

The movement of substances across a membrane against their concentration gradient, requiring energy.

Exocytosis

The process of transporting substances out of the cell using vesicles that fuse with the plasma membrane.

Endocytosis

The process by which cells take in substances by engulfing them in a vesicle; includes phagocytosis, pinocytosis, and receptor-mediated endocytosis.

Phagocytosis

A type of endocytosis in which a cell engulfs large particles or cells.

Pinocytosis

A type of endocytosis in which a cell engulfs extracellular fluid and small molecules.

Receptor-mediated endocytosis

A type of endocytosis that involves the uptake of specific substances based on their binding to receptors on the cell surface.