12.10 Gas Exchange Flashcards
for survival an organism must to what effectively with its environment
exchange materials
examples of materials that need to be exchanged -> respiratory gases
O2 and CO2
examples of materials that need to be exchanged -> nutrients
glucose, amino acids and lipids
examples of materials that need to be exchanged -> excretory products
CO2 and Urea
examples of materials that need to be exchanged -> other
heat
exchange takes place at the what of the organism
surface
the materials absorbed are what by the cell
used (assimilated)
the cell / cells of the organism make up its…
volume
for exchange to be effective…
the SA of the organism must be large compared to its volume
the SA to V ratio gets smaller as what
the object gets larger
SA to V ratio decreases as an organism gets…
larger
O2 is required to produce what during what
ATP
aerobic respiration
when is CO2 produced and as what
produced as a waste product during this process (aerobic respiration)
what does this produce (when CO2 is produced in aerobic respiration as a waste product)
produces concentration gradients of these gases in opposite directions
all organisms rely on what for the exchange of O2 and CO2 down their concentration gradients
diffusion
single celled organisms (protists and prokaryotes) and some small multicellular organisms have what to meet their gas exchange needs by what across their cell membranes
have large enough SA to V ratio
by diffusion
larger organisms (humans, other mammals, insects and fish) have what (by comparison) so cannot rely on what (alone) to meet the oxygen demands to what
have relatively small SA to V ratios
can’t rely on diffusion (alone)
demands to all of their cells
therefore larger organisms have developed what and systems which have what to ensure the what
developed specialised gas exchange surfaces
have adaptations
ensure the rapid diffusion of gases
larger organisms have…
a smaller SA to V ratio
smaller organisms have…
a larger SA to V ratio
fick’s law (equation)
rate of diffusion = (SA x conc gradient) / diffusion distance or pathway
what makes a good exchange surface
- large SA
- large conc gradients
- thin exchange surface (few membrane or thin walls)
dilema of terresterial (land living) insects
the need for gas exchange vs the need to conserve water
gas exchange insects: the most effective surface for gas exchange is a…
a large, thin and permeable area