Page 95 - Science Course 1 (Book 1)
P. 95
Mo3-L5a: How Does Material Enter and Leave Cells?
Key Concept Key Concept
How do materials enter and leave cells? How does cell size affect th transport of
materials?
Cell Size and Transport SUMMARY
How Does Material Enter and Leave Cells?
The area of the cell membrane must be large
compared to its volume so that substances can Small molecules
move into and out of the cell. can move from an
area of higher
The area of the cell membrane is the cell’s surface concentration to
area. an area of lower
concentration by
The volume is the amount of space inside the cell. diffusion.
In facilitated
diffusion,
proteins trans-
port larger
x9 x4 x1 molecules
through a cell
Surface Area membrane.
Some molecules move
from areas of lower
concentration to areas
of higher concentration
through active transport.
x27 x8 x1
88
