unit 3

what is active transport?

where substances need to be moved from an area of high concentration to an area of low concentration against a concentration gradient.

NEEDS ENERGY--- this comes from cellular respiration

1 of 3

two situations it happens in:

  • against a concentration gradient
  • when a molecule is too large to move through the particually-permiable membrane
2 of 3

How are your lungs adapted to make gas exchange as

they have ALVEOLI which are adapted to make it as efficient as possible

o2 into blood by diffusion             thin alveoli walls to make it as easy as possible

co2 out by diffusion                     moist so it can disolve

large surface area

3 of 3


No comments have yet been made

Similar Biology resources:

See all Biology resources »