organisms exchange substances

Question 1

when surface area increases what happens

Answer 1

sa:vol ratio decreases

Question 2

where does gas exchange occur for single celled organisms

Answer 2

through the membrane

Question 3

what are adaptations for diffusion

Answer 3

steep concentration difference
good blood supply
large surface area (alveoli)
thin membrane (short diffusion distance)

Question 4

what is flick’s law of diffusion

Answer 4

rate of diffusion = sa x concentration difference/diffusion distance

Question 5

what sa:vol ratio do fishes

Answer 5

small

Question 6

what type of membrane do fishes have

Answer 6

impermeable membrane (gases can’t diffuse through membrane)

Question 7

what is the lamella in fish

Answer 7

main site of gas exchange

Question 8

what are adaptations for fish

Answer 8

counter current flow (opposite of parallel flow) of water & blood maintains steep concentration gradient along whole length of gill
large number of gills, filaments, lamellae and capillaries which increases sa

Question 9

what are the steps for fish gas exchange

Answer 9

fish opens mouth so water can flow in, then closes it to increase pressure
water passes through lamella, oxygen diffuses into bloodstream (capillaries)
waste co2 diffuses into the water & flows back out of the gills