Cell Biology!
Shouldn’t this be review… ;(
Transport Across the Membrane:
Transport
Type
Passive Transport/Diffusion
Active
Transport
Simple
Diffusion
Facilitated
Diffusion
Osmosis
Types of
Molcules
Small &
Nonpolar (like
gases)
Smaller than
a protein
Water
anything
Concentration
Gradient
High > low
High > low
Low >High (in
terms of
solute)
Low > High
Through
protein?
❌
✅
Specific to the
molecule,
(usually)
unidirectional,
can be closed
off
✅
Aquaporin:
rapidly
transport a
LOT both
ways
✅
Use Energy?
❌
❌
❌
✅
Direct Transportation (avoiding membrane): for LARGE(r than a protein) molecules
●Endocytosis: into the cell
○Most flexible cells create pseudopods (branches like of an amoeba)
and surround the molecule with the cell membrane
■Contained within a vesicle inside the cell
○Phagocytosis: “eating”
○Pinocytosis: “drinking” (Hint: ﮯﻧﯾﭘ)
●Exocytosis: OUT of the cell
○Vesicle joins with cell membrane to essentially dump out the
molecule(s)
■The cell membrane manages to rearrange itself
