diffusion and exchange surfaces. Flashcards
1
Q
define diffusion.
A
the net movement of particles from an area of high concentration to an area of low concentration.
2
Q
define exchange surface area.
A
place that substances are moved across membranes in an organism.
3
Q
how do dissolved substances move in and out of cells?
A
by diffusion.
4
Q
what size molecule can move through the membrane?
A
very small.
5
Q
only small molecules can move the membrane. what is it called?
A
semi-permeable.
6
Q
examples of molecules that can cross across the membrane.
A
glucose.
oxygen.
amino acids.
water.
7
Q
examples of molecules that can’t diffuse across because they are too large.
A
starch.
protein.
