Surface Area to Volume Ratio

Question 1

how do molecules move in and out of cells

Answer 1

diffusion

Question 2

what is surface area volume ratio

Answer 2

the ratio between surface area and volume of an organism eg single cell organisms have huge surface area for their volume

Question 3

what happens to surface area volume ratio as organisms get larger

Answer 3

it falls rapidly

Question 4

why is it bad that large organisms have a small surface area volume ratio

Answer 4

cells on the surface of organisms can diffuse to get organisms but not enough oxygen can diffuse into cells further in

Question 5

how do fish get oxygen

Answer 5

• oxygen rich water passes into the mouth it then flows over the gills where the oxygen is transported into the bloodstream
  -gills are covered in fine filaments, this is where gases pass in and out of the blood
  -deoxygenated blood passes into the filament, oxygen diffuses from the water into the blood, oxygenated blood returns to the body

Question 6

what adaptations do the filaments on gills have

Answer 6

• provides gills with large surface area
  -thin membrane (shorter diffusion pathway)
  -effecient blood supply to transport oxygenated blood and ensure concentration gradient is always high