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BIOLOGY II
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SCIENCE NEWS Water issues have become an
extremely pressing global threat.
With climate change come
unprecedented environmental
impacts: torrential
flooding
insome areas, droughts i
n others,
rising and falling sea levels. Add
to that the threat of
overpopulation
--
and the demandand pollution a
swelling
population
brings
--
and
water becomes one of the
paramount environmental issues to
watch for in the next generation.
Water treatment plants and
systems are now adapting reverse
osmosis to address some of these
concerns. In Perth, Australia
(notably dry and arid, yet
surrounded by sea), nearly 17
percent of the area's drinking
water is desalinated sea water
that comes from a reverse
osmosis plant [source:
TheEconomist
]. Worldwide, there arenow over 1
3,000 desalination
plants in the world, according to
the International Desalination
Association.
http://science.howstuffworks.com/nature/natural-disasters/flood.htmhttp://science.howstuffworks.com/nature/natural-disasters/flood.htmhttp://people.howstuffworks.com/population.htmhttp://people.howstuffworks.com/population.htmhttp://www.economist.com/node/11484059http://www.economist.com/node/11484059http://www.economist.com/node/11484059http://www.economist.com/node/11484059http://www.economist.com/node/11484059http://www.economist.com/node/11484059http://people.howstuffworks.com/population.htmhttp://science.howstuffworks.com/nature/natural-disasters/flood.htm7/29/2019 Biology II Presentation
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CELLS
Are the basic building blocks of all
living things.
They provide structure for the body,
take in nutrients from food, convert
those nutrients into energy, and
carry out specialized functions.
Cells have many parts.
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DIFFUSION
is the movement of
particles
(atoms, ions or
molecules
) from a region in which
they are in higher concentration
to regions of lower
concentration.
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Here the molecules move out of the
liquid and into the air by diffusion.
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OSMOSIS
Is the passage of water from aregion of high water concentrationthrough a semi-permeable membraneto a region of lower concentration
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SEMI-PERMEABLE
MEMBRANE Are very thin layers of material
which allow some things to passthrough them but prevent otherthings from passing through.
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Condition Cell Solution EnvironmentalSolution
Movement ofWater as Solvent
1. Solute
concentration in theenvironment is lower
than in the cell;
solvent is higher in
the environment.
2. Solute
concentration in the
environment is higher
than in the cell;
solvent is lower in
the environment.
3. Soluteconcentration in theenvironment is equalto that in the cell.
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ASSIGNMENT/ HOMEWORK
Do try this at home:
EGG OSMOSIS -you need eggs, vinegar, scales toweigh egg if possible.
1. Weigh the uncooked eggs and carefully place themin large glass of vinegar.
2. Cover and leave for 2 days. It might look a bitlike beer but please dont drink the liquid.
3. Remove the eggs and rinse gently under the tapwater. All of the shell should be gone by now.
4. Weigh the egg again. Record all your observationsand be ready for class discussion.