Untitled Flashcards Set

Facilitated diffusion

Movement of molecules across the cell membrane through protein channels, from high to low concentration, without energy.

Diffusion

Passive movement of particles from an area of high concentration to an area of low concentration.

Osmosis

Diffusion of water molecules across a selectively permeable membrane from a region of lower solute concentration to higher solute concentration.

Equilibrium

State where the concentration of molecules is equal throughout a space, with no net movement in any direction.

Selectively permeable membrane

A membrane that allows some substances to pass through while blocking others.

Hypotonic

A solution with a lower concentration of solutes compared to another solution, causing cells to swell as water enters.

Hypertonic

A solution with a higher concentration of solutes compared to another solution, causing cells to shrink as water exits.

Isotonic

A solution with an equal concentration of solutes as another solution, causing no net water movement into or out of cells.

Cholesterol

A lipid molecule within the cell membrane that helps maintain its fluidity and stability.

Phospholipid bilayer

The fundamental structure of the cell membrane, consisting of two layers of phospholipids with hydrophilic heads and hydrophobic tails.

Fatty Acid Tails

The hydrophobic (water-repelling) part of phospholipids that face inward in the bilayer.

Phosphate Heads

The hydrophilic (water-attracting) part of phospholipids that face outward towards water in the bilayer.

Peripheral Protein

Proteins attached to the exterior or interior surfaces of the cell membrane.

Vesicle

Small, membrane-bound sacs that transport substances within or outside the cell.

Integral protein

Proteins embedded within the cell membrane that can span the entire membrane.

Glycoprotein

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

Glycolipid

Lipids with carbohydrate chains attached that are involved in cell recognition and membrane stability.

Passive Transport

Movement of substances across the cell membrane without the use of energy, down their concentration gradient.

Active transport

Movement of substances across the cell membrane using energy, often against their concentration gradient.

Exocytosis

The process by which cells expel materials in vesicles to the outside environment.

Endocytosis

The process by which cells take in materials by engulfing them in vesicles.