3A-Exchange and transport systems- gas exchange Flashcards
what is needed to increase the rate of diffusuon
large surface area
thin- provides short diffusion pathway across gas exchange surfaces
also organism maintains a steep concentration gradient
single-cell organisms gas exchange
organisms absorb and release gases by diffusion through their cell-surface membranes
what increases the rate of diffusion of single celled organisms
relatively large surface area
thin surface
short diffusion pathway
image of section of gill filaments
pg 142
what are the gill fillaments and lamella for
to increase surface area
how is the lamellae adopted to its function
lots of blood cappilaries and thin surface layer
how does counter-current system work
water with high oxygen concentration flows next to blood with lower oxygen concentration. steep concentration gradient kept between them
what is a counter current
water with a relatively high oxygen concentration flows next to blood with with a lower oxygen concentration. steep concentration gradient kept between them
main gas exchange surface in dicotyledonous plants
mesophyll cells
what does the stomata do
open and closes to allow gas exchange and closing if the plant loses too much water
what does the guard cell do
controls opening and closing of the stomata
process of gas exchange in insects
air moves into the trachea through pores called spiracles. oxygen travels down the concentration gradient towards the cells. trachea branches off into smaller tracheoles
properties of tracheoles
thin permeable walls
too much water loss in insects
close spiracles using muscles, waterproof waxy cuticle and hairs around spiracels reduce evaporation
too much water loss in plants
cell becomes flaccid closing the pore
