Passive and Active TransportUnit 2- Cell Structure and Function
Outcomes:• Identify the factors
which influence the rate and direction of diffusion.
• Identify how osmosis is related to diffusion and the value of osmosis to living organisms.
• Examine the mechanisms of active transport by identifying and explaining the two processes.
• Compare the similarities and differences between active and passive transport.
**Don’t have to write these out**
Cellular Transport Cellular transport moves substances
_________the cell and moves substances ________and ________of the cell
There are 2 types:1. _________ Transport2. _________ Transport
Passive Transport These types of transport do not require
energy a) Diffusionb) Facilitated Diffusionc) Osmosis
A) Diffusion Remember from years before that
particles in solids, liquids, and gasses are in constant ___________ ___________(Particle Theory of Matter)
Substances dissolved in water move constantly in random motion
The random _________ of these _________ creates DIFFUSION
The amount of a substance in a certain area is called ___________________
Substances diffuse from an area of _________ concentration to an area of _________ concentration
Watch the following video and draw the diagram on the next page: http://
www.youtube.com/watch?v=Um6OoN81rb4
Diagram of Diffusion
Diffusion occurs until there is an __________ _______________ of particles in an area/cell
The particles continue to move randomly, but there is _____ ____________ ___________ this is called DYNAMIC EQUILIBRIUM
Rate of Diffusion 3 main factors affect the rate that
diffusion occurs1. _______________
When concentration is high, diffusion happens quickly because there are more particles to collide with each other
2. _______________ When temperature increases, the particles
collide more quickly3. _______________
When pressure increases, the particles collide more quickly
B) Facilitated Diffusion While water can diffuse readily across a
plasma membrane, most other substances need help
Happens through ____________ and _____________ proteins
The CHANNEL PROTEINS in the plasma membrane of the cell are used to diffuse ions and small molecules across the cell membrane (draw the diagram below)
http://kentsimmons.uwinnipeg.ca/cm1504/Image132.gif
CARRIER PROTEINS are also used to move substances across a cell membrane by ___________ _________ to help diffusion in a cell (Draw the diagram)
http://www.biologycorner.com/resources/simpdiff.jpg
C) Osmosis The _________ of water __________ a
selectively permeable ____________ is OSMOSIS
_____________ the movement of water across the plasma membrane is an important factor in maintaining homeostasis
(draw the next diagram)
http://www.biologycorner.com/resources/osmosis.jpg
If the __________________ of solute is higher on one side of the cell membrane, the water will move _____________ the __________ solute __________________
This diffusion happens until dynamic equilibrium occurs
Isotonic Solution When a cell is in a solution that has the
same concentration of water and solutes is said to be in an ISOTONIC solution
Water moves into and out of the cell at the same rate and cells keep their ______________ ___________
Hypotonic Solution If a cell is in a solution that has a lower
concentration of solute, the cell is said to be in a __________________ solution
There is more water outside of the cell than inside the cell which causes __________ to move __________ ____ ______
The water moving into the cell creates ___________ ___________
In an ________ cell, the water may enter the cell so much so that it ___________
A plant cell will ________ burst if there is a high osmotic pressure ____________ the cell __________ is very _________
Hypertonic Solution When the ________________ of the solute
____________ of the cell is _______than inside
________ __________ _________ the cell ___________ cells may __________ because
of water loss _______ cells ________because the water
vacuole is empty
Draw the diagram:
http://4.bp.blogspot.com/-yiAZAMJRq4s/Ta79K3vVk8I/AAAAAAAAACE/MhfD0z_ABi8/s1600/hypo.jpg
Video Explanation http://
www.youtube.com/watch?v=AYNwynwaALo
Active Transport This happens when substances have to move
from an area of __________ concentration to an area of __________ concentration
This process makes sure that cells have the proper ___________ of substances inside of them
These forms of cellular transport REQUIRE the use of ______________ by the cell
a) Pumps (carrier proteins)b) Endocytosis/Exocytosis
A) Pumps (Carrier Proteins) __________ proteins can move
substances against a concentration gradient
Some pumps move one type of substance in one direction across the plasma membrane
Other pumps move two substances in both directions across the plasma membrane
Sodium Potassium Pump This is a common type of pump moves 3 ___________ ions ______ of the cell moves 2 ___________ ions ______ the cell ATP (a form of energy) _______ _______ into
ADP to do this Video demonstration
http://www.youtube.com/watch?v=Q73uJ8WlY_E
http://4.bp.blogspot.com/_207DNIaL-gc/TOaSu8u3q7I/AAAAAAAAAV4/9QLnFO82wQA/s1600/07_16SodiumPotassiumPump.jpg
B) Endocytosis & Exocytosis Particles that are too large to travel
through the plasma membrane leave or enter the cell differently
Endocytosis when a cell ______________ something
_____________ of the cell The cell membrane __________ ________
and takes the substance inside the cell The substance is now in a __________ to
travel throughout the cell
Exocytosis Is when substances ___________ the cell
by vesicles ____________ the plasma _______________ to expel (get rid of) the substance
http://www.kscience.co.uk/as/module1/pictures/endoexo.jpg
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