9..2 Flashcards
Define simple diffusion
The movement of molecules from an area of higher concentration to an area of lower concentration without the need for energy.
What is facilitated diffusion?
The process of moving molecules across a membrane through protein channels from an area of higher concentration to an area of lower concentration without energy.
Define osmosis
The diffusion of water molecules through a selectively permeable membrane from an area of lower solute concentration to an area of high.
What does hypertonic mean?
A solution with a higher concentration of solutes.
What does hypotonic mean?
A solution with a lower concentration of solutes.
What does isotonic mean?
A solution with an equal concentration of solutes.
Define active transport
The movement of molecules across a membrane against their concentration gradient, requiring energy.
What is endocytosis?
The process by which cells internalize substances by engulfing them in a vesicle.
What is exocytosis?
The process by which cells expel materials in vesicles.
List the properties and structure of phospholipids
Composed of a hydrophilic head
Composed of two hydrophobic tails
Form bilayers in environments
Provide barriers in cellular membranes
Identify parts of the cell membrane and their functions
Phospholipids: form the bilayer
Proteins: assist in transport and communication
Cholesterol: maintains membrane fluidity
Carbohydrates: involved in cell recognition
Explain the importance of surface area: volume ratio
A higher surface area to volume ratio allows for more efficient transport of materials into and out of the cell.
Compare and contrast different types of transport
Transport can be categorized as:
Simple diffusion: moves down the concentration gradient, requires no energy
Active transport: moves against the concentration gradient, requires energy
Facilitated diffusion: requires transport proteins, moves down the concentration gradient.
Predict which way solutes will diffuse across a membrane
Solutes will diffuse from an area of higher concentration to an area of lower concentration until equilibrium is reached.
Predict which way water will diffuse across a membrane via osmosis
Water will diffuse from an area of lower solute concentration to an area of higher solute concentration.
This movement continues until solute concentrations are equal on both sides of the membrane.
