Gas Exchange And Diffusion Flashcards
What is diffusion
The net movement of molecules from an area of high concentration to low concentration
Transports water, oxygen and CO2
No energy or membrane required
What is osmosis
The movement of water molecules form an area of high water potential to one of low water potential through a partially permeable membrane
No energy required
Effects on the rate of diffusion:
Temperature Concentration gradient Surface area to volume ratio Molecular mass Distance
Concentration gradient effect
The greater the difference in concentration, the quicker the rate of diffusion
Temp effect
Higher temps, more KE, faster rate
Surface area:volume effect
The greater the SA:V, quicker rate
Molecular mass effect
As the MM increases, slower rate
Distance effect
Smaller distance, quicker rate
Examples of diffusion
Leaf
Alveoli
Small intestine
Animal cells in pure water/hypotonic solution/distilled water
High to low - outside to inside
Swells
Animal cells in isotonic solution
No net change
Animal cells in hypertonic solution/sugary solution
High to low - inside to outside
Crenate
Plant cells in dilute solution
Water enter cells - turgid
Plant cells in a concentrated solution
Water leaves cells
Flaccid - plant wilts
What is active transport
The movement of molecules across a cell membrane into a region of higher concentration requiring energy from respiration
