Diffusion, Osmosis & Active Transport Flashcards
What is the definition of diffusion?
The movement of particles in a liquid or gas from an area of high concentration to an area of low concentration
What is the definition of concentration?
The number of particles in solution, relative to the volume of the solution
Is diffusion passive or active?
Passive
Does it require energy? Diffusion
No, it’s passive, so will happen anyway as particles move down the concentration gradient (high > low)
Which substances move in/out of cells by diffusion?
Oxygen, Carbon Dioxide, Glucose
In which tissues does diffusion occur?
Lungs (across the alveoli); small intestine; kidneys; plant leaves
What will affect the rate of diffusion?
• Concentration gradient
• Temperature
• Surface area
What is osmosis?
The diffusion of water from a dilute solution (high water concentration) to a concentrated solution (low water concentration)
How does active transport differ from diffusion?
• Moves against the concentration gradient
• Requires energy
• Use of protein carriers
Where does the energy come from?
Released through respiration in the mitochondria
Where do we need active transport?
• Transport mineral ions into plant root hairs from dilute concentrations in soil
• absorb sugar from lower concentrations in the gut into blood
What is the substance moved in diffusion?
Dissolved solutes
What is the substance moved in osmosis?
Water
What is the substance moved in active transport?
Dissolved solutes
Is energy needed in osmosis?
No
