9.2 Transport Flashcards
What is simple diffusion?
The movement of molecules from an area of higher concentration to an area of lower concentration without the use of energy.
Simple diffusion occurs directly through the phospholipid bilayer.
What is facilitated diffusion?
The process of transporting molecules across a membrane via protein channels without energy.
Facilitated diffusion is specific to certain molecules that cannot easily cross the lipid bilayer.
What is osmosis?
The diffusion of water across a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration.
Osmosis is crucial for maintaining cell turgor pressure.
What does hypertonic mean?
A solution with a higher concentration of solutes compared to another solution.
In a hypertonic solution, cells may lose water and shrink.
What does hypotonic mean?
A solution with a lower concentration of solutes compared to another solution.
In a hypotonic solution, cells may gain water and swell.
What does isotonic mean?
A solution with an equal concentration of solutes compared to another solution.
In an isotonic solution, there is no net movement of water into or out of the cell.
What is active transport?
The movement of molecules against their concentration gradient, requiring energy (ATP).
Active transport is essential for maintaining concentration differences across membranes.
What is endocytosis?
The process by which cells engulf substances from their external environment.
Endocytosis includes processes like phagocytosis and pinocytosis.
What is exocytosis?
The process by which cells expel materials to the outside environment.
Exocytosis is important for secretion of hormones and neurotransmitters.
Why is the surface area: volume ratio important?
It affects the efficiency of transport processes and cellular metabolism.
A higher ratio allows for more efficient exchange of materials with the environment.
What are the key differences between types of transport?
Types of transport can be compared based on:
* Type of particles moved
* Direction relative to concentration gradient
* Requirement for transport proteins
* Requirement for energy
Active transport requires energy and moves against the gradient, while passive transport does not.
Which way will solutes diffuse across a membrane?
Solutes will diffuse from an area of higher concentration to an area of lower concentration.
This process continues until equilibrium is reached.
Which way will water 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 aims to equalize solute concentrations on both sides of the membrane.
