Transcript Cell Transport - Heritage High School

Introducing Cell Transport
Cell Transport
 Concentration Gradient


Concentration – The amount of solute in a
solution
Gradient – A measure of how much
something changes when you move from one
region to another.
 Put ‘em together and what do you get?

Concentration Gradient - measurement of
how the concentration of something changes
from one place to another.
Passive Transport
 Passive Transport – Molecules moving from
an area of high concentration to low
concentration.

No energy needed
Diffusion
 The process by which molecules spread from
areas of high concentration, to areas of low
concentration.
Equilibrium – Concentration is equal
throughout solution.
Diffusion Animation

Osmosis
 The movement of
water molecules
from high
concentration to
low concentration
Osmosis
 Hypertonic: Water diffuses out of cell

(Cell Shrinks)
 Hypotonic: Water diffuses into cell

(Cell swells)
 Isotonic: Equal rate of water diffusion into
and out of the cell

(Cell Stays the Same)
http://staff.jccc.net/aalarabi/memb_related_mov.htm
Facilitated Diffusion
A form of diffusion facilitated by transport
Proteins also known as carrier proteins
Facilitated Diffusion
 http://highered.mcgraw-
hill.com/sites/0072495855/student_view0/chapter2/animation__how_fa
cilitated_diffusion_works.html
Active Transport
 Active Transport: The Transport of a
substance across the cell membrane against
its gradient
 Requires Energy ( usually ATP)
http://staff.jccc.net/aalarabi/memb_related_mov.htm
Sodium/Potassium Pump
Bulk Transport
 Endocytosis- The movement of a substance
into a cell by a vesicle
 Cell membrane forms pouch around
substance and then pinches off
Bulk Transport
 Exocytosis- The movement of substance by
a vesicle to the outside of a cell
 Vesicles fuse with cell membrane
Cells Must Be Small
 All substances that enter or leave the cell
must cross that cell’s surface
 Small cells can exchange substances better
than large cells
 They don’t have to travel as far to reach the
center
Cell Size: Surface Area To volume