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Biology - Exchanging materials - Coggle Diagram
Biology - Exchanging materials
surface area to volume ratio
larger organism, smaller surface area compared to volume
as organisms get bigger and more complex
smaller SA : V
not enough substances can diffuse from outside surface to supply entire volume
need exchange surfaces
ADAPTATIONS
thin membrane
short distance to diffuse
large surface area
lots of substance can diffuse at once
lots of blood vessels
get substances in and out of blood quickly
steep concentration gradient
Gas exchange surfaces
ventilated (air)
steep concentration gradient
Gas Exchange in Lungs
transfer oxygen transfer oxygen to blood, remove water carbon dioxide
ALVEOLI
little air spaces
gas exchange takes place
Specialised
enormous surface area
moist lining
very thin walls
good blood supply
conc. gradient
Digestion in Gut
VILLI
tiny little projections - millions
increase surface area
digested food absorbed more quickly into blood
Specialised
single later of surface cells
very good blood supply
con. gradient
Gas Exchange in Fish
GILLS
thin plates - gill filaments
covered in LAMELLAE
increase SA
lots of blood capillaries
speed up diffusion
blood flows in one direction, water in opposite
large conc. gradient
thin surface layer of cells
minimise diffusion distance
conc. of oxygen in water is higher than in blood
Gas Exchange in Leaves
CO2 diffuses into air spaces, then into cells - photosynthesis
Adaptations
underneath of leaf is an exchange surface
CO2 diffuses through little holes
STOMATA
GUARD CELLS close stomata if plant is losing water faster than is being replaced by roots
otherwise, plant would wilt
Oxygen (produced in photosynthesis) and water vapour
diffuse out through STOMATA
walls of cells
air spaces inside leaf increase SA
more chance of CO2 to get into cell