Connect!
• Who is this guy?
• Have you ever heard of osmosis before?
• What does it mean?
OSMOSIS
• Simply refers to the diffusion of water
across a membrane, from high to low
concentration
Osmosis of water depends on the amount
of “stuff” (solute) dissolved in the water on
each side of the membrane.
*More solute, less water…
*Less solute, more water…
solute
water
Which way will the water diffuse?
Why do these cells do this?
A plant cell doesn’t react in quite the same way as
an animal cell bc it has a cell wall.
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Chunk!
Define diffusion.
Does diffusion occur in living or non-living environments?
Does diffusion require the cell to use ATP?
Describe diffusion between a blood capillary and a lung
alveolus.
Where else in the body does diffusion occur?
What type of substances can diffuse across the cell
membrane, generally?
Define osmosis.
What is relationship btwn amount of solute and amt of
water?
What happens to red blood cells in isotonic solution?
Hypotonic??? Hypertonic???
What happens to plant cells?
Active Transport
• Unlike diffusion, active transport requires
energy (ATP).
• Substances move from an area of low to
an area of high concentration.
Active transport is a lot like rolling boulder up a
hill. The natural tendency is for the boulder to
roll down the hill, just as the natural tendency of
molecules is to equally distribute themselves on
either side of a membrane. However, by
spending some energy to push the boulder
higher and higher, you have the potential to use
the boulder to do useful work that would be
impossible otherwise. The same is true for
molecules.
Phagocytosis – when a cell
engulfs a solid particle, by an
indenting of the cell membrane
White Blood Cells engulf pathogens (germs).
Organisms that live in fresh water have to
constantly spend energy to pump out the water
that flows in by osmosis.
Chunk!
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Define active transport.
How is it different from passive transport?
Why is active transport like rolling a boulder up a hill?
What does size have to do w/ A.T.?
Name 3 substances that cross the membrane by A.T.
What is phagocytosis?
What human cells carry out phagocytosis?
• Explain this analogy of active transport.
• Explain this cartoon. Think of a caption!
Just for Fun…
Images
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photo - http://virtualbiologytutor.co.uk/images/
Active Transport - http://www.bio.miami.edu/~cmallery/150/memb/c8.7x17.transport.jpg
Ion pumps - student.ccbcmd.edu/.../images/sppump.gif
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3 Types - www.nicksnowden.net/.../membrane_transport.htm
Large molecules - www.goldiesroom.org/Multimedia/Bio_Images/06%
Boulder - http://neftriplecrunch.files.wordpress.com/2008/12/sisyphus.jpg
Cartoon - http://www.cartoonstock.com/newscartoons/cartoonists/dcl/lowres/dcln17l.jpg
Red Blood Cells - https://www.msu.edu/~knickerk/webquest/osmosis2.gif
Osmosis animation - http://people.eku.edu/ritchisong/osmosis3.gif
Osmosis animation - http://people.eku.edu/ritchisong/osmosis3.gif Contractile vacuoles http://images.google.com/imgres?imgurl=http://leavingbio.net/OSMOSIS%2520AND%2520DIFFUSION_files/imag
e001.gif&imgrefurl=http://leavingbio.net/OSMOSIS%2520AND%2520DIFFUSION.htm&usg=__iuaKbyYmgJsu1Wr
qPQdHP0w1nDE=&h=300&w=300&sz=8&hl=en&start=2&itbs=1&tbnid=zWgKv816n22UwM:&tbnh=116&tbnw=11
6&prev=/images%3Fq%3Ddiffusion%2Banimation%26gbv%3D2%26hl%3Den
Blood and plant cells - http://www.emc.maricopa.edu/faculty/farabee/BIOBK/bloodcells.gif
Exocytosis - www.emc.maricopa.edu
Contractile vacuole - dtc.pima.edu/.../parameciummovie.gif
Osmosis jones http://images.google.com/imgres?imgurl=http://www.joblo.com/images_movie_reviews/osmosis_jones.jpg&imgref
url=http://www.joblo.com/reviews.php%3Fmode%3Djoblo_movies%26id%3D461&usg=__lxDZcq1m2CxBggrO_Rv
0fc2tN5Q=&h=224&w=160&sz=10&hl=en&start=14&itbs=1&tbnid=MqLHQRQV2hQ64M:&tbnh=108&tbnw=77&pre
v=/images%3Fq%3Dosmosis%2Bjones%26gbv%3D2%26hl%3Den
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