Download active transport

Cells, Cells, Cells
Active Transport
and
Passive Transport
Active Transport
 Active transport is the movement of
solutes and molecules across the cell
membrane WITH the use of energy
(ATP – adenosine tri-phosphate) by the
molecule
Active Transport
 There are different
types of active
transport that occurs
in cells:
 Endocytosis –
the process of taking
material INTO the
cell by means of infoldings, or pockets,
of the cell membrane
Active Transport
 Exocytosis – is the process of releasing
material from the cell by means of small
vesicles (bubble-like membranous structure)
Active Transport
Passive Transport
 Passive transport is the movement
of solutes and molecules across the
cell membrane WITHOUT the use of
energy (ATP – adenosine triAlso includes
phosphate) by the molecule
facilitated
diffusion of
larger molecules
through a protein
channel
Passive Transport
 Diffusion – the
movement of
substances from
an area of high
concentration to
areas of low
concentration
Examples of small molecules:
carbon dioxide, oxygen, small
non-polar molecules
Shows the random movement of
small molecules down (with) the
concentration gradient until
molecules are evenly dispersed
(in equilibrium)
Passive Transport
 Facilitated
diffusion – the
movement of
substances with their
concentration
gradient (high to low
concentration)
through protein
channels in the cell
membrane
Passive Transport
 Osmosis – the
movement of
water across a
semi-permeable
membrane from
an area of high
concentration to
an area of low
concentration
Passive Transport
 a. Water moves
from hypotonic to
hypertonic
solutions
Passive Transport
 b. Water moves in
equilibrium (equal
amounts) in both
directions across a
membrane with
isotonic solutions
 Factors that affect the movement of substances
by passive transport include: temperature; size
of the molecule; whether molecule is a solid,
liquid, or gas; and concentration amount