Movement in and out of cells Flashcards
What is Diffusion?
Diffusion is the net movement of molecules from a region of high concentration to a region of lower concentration down a concentration gradient
What is the movement of molecules by diffusion across a cell membrane called?
Passive movement
What 5 factors affects diffusion and why?
The distance a molecules have to travel - Cell membranes are very thin.
Concentration gradient - The higher the difference in concentration, the higher the diffusion rate.
Surface area - Folds in cell membranes allow higher diffusion rates.
Temperature - Hotter molecules faster, so they also diffuse faster.
Size of molecules - Smaller molecules diffuse faster than big ones.
What is a solution made of?
A solution is made of two parts: Solute and solvent.
What is the solute?
The solute is the substance dissolved in a solvent.
What is the solvent?
The solvent is the substance where the solute is dissolved.
What are substances that can be dissolved in a solvent described as?
They are described as soluble.
What is a universal solvent?
Water
Read
Osmosis is a special kind of diffusion involving water molecules.
When does Osmosis occur?
Osmosis occurs when two solutions are separated by a partially permeable membrane - Like the cell membrane.
What is osmosis?
The diffusion of water from a high dilute solution into a more concentrated one.
Describe osmosis
The water flows from a high water potential to a low water potential region, down a water potential gradient.
Read
Because of the cell wall present in Plant cells, animal and plant cells respond differently to osmotic pressure.
What is is called when substances need/ are transported against the concentration gradient.
Active transport.
What does this require the use of?
Carrier proteins, and energy produced by cell respiration.
