Cell Membrane Flashcards

Cell Membrane

• The cell membrane regulates the entry and exit of substances, maintaining cellular integrity.

Phospholipids

• Composed of a phosphate group, glycerol, and two fatty acid chains, phospholipids form the structural basis of the cell membrane.

Fluid Mosaic Model

• This model illustrates the dynamic and varied arrangement of molecules within the cell membrane, resembling a mosaic.

Selective Permeability

• The cell membrane's selective permeability allows certain substances to pass while blocking others, facilitating controlled transport.

Receptor

• Receptors are proteins that detect signaling molecules, triggering transport mechanisms for substances entering or leaving the cell.

Passive Transport

• Movement of molecules via passive transport occurs from areas of high concentration to low concentration without energy expenditure.

Simple Diffusion

• Simple diffusion allows substances (excluding water) to move freely across the membrane from high concentration to low concentration without assistance.

Concentration Gradient

• A concentration gradient refers to the variation in the concentration of a substance between two regions, influencing diffusion.

Osmosis

• Osmosis specifically refers to the diffusion of water molecules from an area of higher concentration to one of lower concentration.

Isotonic

• In an isotonic state, water concentration is balanced inside and outside of the cell, as is the solute concentration, preventing net movement.

Hypertonic

• In a hypertonic environment, water exits the cell as the outside solution has a higher solute concentration, potentially leading to cell shrinkage.

Hypotonic

• In a hypotonic situation, water enters the cell due to a higher solute concentration inside, which may cause the cell to swell and potentially burst.

Facilitated Diffusion

• Facilitated diffusion involves the passive transport of larger molecules like sugar with the assistance of transport proteins across the cell membrane.

Active Transport

• Active transport moves substances against their concentration gradient from low to high concentration, requiring energy.

Endocytosis

• Endocytosis is the process by which cells engulf food or fluid, a form of active transport allowing for bulk intake.

Exocytosis

• Exocytosis is the mechanism by which cells expel waste or proteins, utilizing active transport to release materials from the cell.