Transcript Plasma Membrane

Active
Transport
Warm Up!
Imagine that a human blood cell,
which is 3% salt, is placed in a beaker
of pure water.
1.
2.
3.
Draw a picture of this scenario
Is it in a hypertonic or hypotonic
solution?
Will it shrink or swell? Why?
3% Na
97% H2O
solution
100% H2O
Red Blood Cell
 Hypotonic
 Swell
Animal Cells
Animal
cells placed into a
hypotonic solution will
EXPLODE.
Hypotonic
Red
Blood
Cell
Animal Cells
Animal
cells placed into a hypertonic
solution will SHRIVEL.
Hypertonic
Red
Blood
Cell
Plant Cells
 In
a hypotonic environment, the vacuole fills
with water. Cell wall keeps it from exploding
Water
Cell
Wall
Water
Central
Vacuole
Water
Plant Cells
 In
a hypertonic environment (loss of water),
the plasma membrane pulls away from the
cell wall (vacuole empty).
Water
Water
plasma membrane
Cell
Wall
Water
To Do:
 Worksheet:
 “tonicity”
Osmosis & Tonicity
means predicting how a cell will
react in a solution (hypotonic, hypertonic,
isotonic)
Active Transport
The
movement of molecules
across the plasma membrane
using energy (ATP).
ATP
Adenosine
triphosphate
Made in the mitochondria
Has high energy bonds
Bonds can be broken to
release energy for use in the
cell
4 volunteers, please!
When is Active Transport
Needed?
1. Moving from LOW to HIGH
concentration
Called “against the concentration
gradient”
Requires Energy from ATP
Ex: Protein pumps
 Some
membrane proteins use
energy to pump substances in and
out of the cell.
 Volunteers, please!
 http://highered.mcgrawhill.com/sites/9834092339/student_
view0/chapter5/sodiumpotassium_exchange_pump.html
2. Moving LARGE molecules
into or out of the cell
Example: Endocytosis
ENTRY
into cell
Portion
of the membrane surrounds or
engulfs a large molecule outside cell.
Requires
Energy from ATP
Types of Endocytosis
Pinocytosis:
endocytosis of liquids
Phagocytosis: endocytosis of
particles
Example: White Blood Cell
destroys bacteria
Example: Amoeba eating
Exocytosis:
EXPORT
of materials
OUT of the cell (wastes,
cell products)
-
Requires Energy from ATP
Active Transport
in the Human Body
 Protein

Pump
Nerve cells- Sodium Potassium Pump (electric signals)
 Pinocytosis


Intestine cells absorb water/nutrients
Egg cell absorbs water/nutrients
 Phagocytosis

White Blood Cells (aka phagocytes) engulf & destroy
bacteria, viruses, old cells
 Exocytosis



Release digestive enzymes
Release hormones
Waste
Closure
Write out the KEY TERMS that
you learned today!