Exchanging Substances Flashcards
Diffusion, Active Transport, Osmosis, Hypertonic/Hypotonic,
Define Duffusion?
> Movement of particles from area of high concentration -> low concentration
Down a concentration gradient
Until equilibrium
What type of process is diffusion?
Passive process
No energy required
What factors affect rate of diffusion?
3
> Temperature
> Surface area
> Concentration Gradient
What happens to rate of diffusion when you increase temperature?
Increases -> particles move faster due to heat energy transferred to kinetic Energy
What happens to rate of diffusion when surface area increases?
Increase -> particles have to spread out further over a larger space
What happens to rate of diffusion when concentration gradient increases?
Increases -> More spreading of particles to other side to reach equilibrium
Define Osmosis?
Movement of water molecules from a dilute to a concentrated solution through a partially permeable membrane
What is a dilute solution?
Low concentration of solute (sugar)
High concentration of solvent (water)
HYPOTONIC SOLUTION
What is a concentrated solution?
High concentration of solute (sugar)
Low concentration of solvent (water)
HYPERTONIC
What is a dilute solution known as?
HYPOTONIC
What is a concentrated solution known as?
HYPERTONIC
What is an Isotonic solution?
Solution that has same salt concentration as cells and blood
Define Active Transport?
> Movement of substances from low concentration-> high concentration
Against a concentration gradient
What type of process is active process?
Energy requiring
Example of Active Transport in plant?
Root Hair Cell:
> Minerals from soil
Example of Active Transport in Animals?
Intestines:
> Sugar in intestine into blood
> Gluscose for respiration
What is meant by semi-permeable?
Allows some substances to pass through but not all
What organisms need exchange surfaces?
Multi cellular
Large
What is surface area?
Area of surface of something
What is volume?
Amount of space and object occupies
How to calculate volume?
Length × Width × Height
How to calculate Surface Area?
Length × Length
How to calculate
Surface area : Volume?
SA : V = SA
——-
V
Bigger SA : V means…..
Diffusion occurs quickest
How is Alveoli (Lungs) adapted to diffusion efficiently?
> Thin walls -> Short diffusion pathway
> Millions -> Bigger SA
> Capillaries surrounding -> Maintain conc gradient
How is small intestine adapted to diffusion?
Villi = Large SA
One cell thick = Short diffusion pathway
Close to blood = Maintain concentration gradient
How are fish gills adapted to diffusion?
Lots of Gill filaments = Large SA
Blood with 02 + CO2 = Maintain concentration gradient
How are Roots adapted to diffusion?
Plant
Large extensions = Large SA
Large vacuole = Maintain concentration gradient
Thin wall = Short diffusion pathway
How is the leaf adapted to diffusion?
Plant
Elongated cells = Large SA
Lots of chloroplasts = Large SA for photosynthesis
Air spaces between cells = Decrease diffusion pathway
How does a large SA increase diffusion?
More surface area for substances to pass
How does a thin cell membrane / wall help diffusion?
Shorter diffusion pathway
How does efficient bloody supply help diffusion?
Good capillary network
Maintains concentration gradient
