Transcript The Tao of the Molecular World

The Tao of the Molecular
World
A hands on approach to understanding
the mantra of molecules in real life.
Today we are going to:
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Check out some of the forces acting on and
between macromolecules.
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Think about how the chemical structures of
biomolecules manifest as properties -even
behaviors - in cells.
Or most importantly…
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Today will be a nuts and bolts exercise in order
to challenge your own particular brand of
creativity and your ability to link these molecular
concepts with the real world.
Translated…
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There is a lot of stuff in this room arraigned in
different groupings.
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There are no real instructions…
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And it’s up to you to figure some stuff out based
on what you already know about biology and
chemistry.
So why don’t I help jump-start your
thinking before we begin…
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Sulfur hexafluoride is about 5X
heavier than air and 35X heavier
than helium.

Inhaling helium makes your voice
pitch higher as it allows you vocal
chords to vibrate faster, SF6 is so
dense, inhaling it would make
your voice much lower.
Sulfur Hexafluoride is great example of molecular
properties we cannot see but do indeed exist!
ChemLancer, Youtube.com
One more
TheTvelvethMonkey, Youtube
It’s easy to live in a world and not
realize the principles that govern it.
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Again, the properties of molecules and their
interactions with one another are real things and
they are amazing at that!
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This example also dispels the myth that in order
to have “weight” or be counted as an effective
molecule you must be large… we just saw a gas
behave much like water.
Why?

Think about H2O, think about the types of
bonds and interactions between polar and non
polar molecules.

Do we all know enough about bonds, polarity
and partial negative and positive charges at this
point? (Psst, you’ll need a basic understanding
to work out some of today’s fun stuff)
Bonding
A Covalent bond:
is a shared pair of electrons
Hydrogen bonds: Hydrogen interaction--partial(+) H atom
attracted to partial(-) oxygen or nitrogen
Greasy: ( = hydrophobic = non-polar) ‘bond’: water doesn’t
play well with others, excludes them.
Ionic bond: + or – charge due to electron gain or loss
What about the 4 big guns of
biological science?
Lipids = greasy water shedders: barriers
Nucleic acids = picky pairers: information
Amino acids = diverse shapes, surfaces & sizes:
machines
Carbohydrates = rich fuel: energy
Static electricity and balloons to
mess up your hair.
You don’t really have to mess up your hair, a
shirt or your neighbors hair should do just fine.
What is ‘static cling’?
How could we use it to investigate these claims
about oil & water?
Use your nose…
What do you notice?
What does the fact of
smelling tell you about
involvement of molecules?
What does smelling different things tell you?
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C10H14O
This is the formula for both smells. What can
you conclude?
Hmm, what about starch..
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Why does bread get stale? Is it simply a loss of water?
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What if you knew that bread will stale even in a moist
environment, and stales most rapidly at temperatures just
above freezing.

What if you knew, that simply placing the bread in the
microwave (without water) would freshen it up once
more?
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So then what is it about bread (or starch) that causes this?
A hint I suppose… but why, why,
why?
Fun with eggs
A lipid bilayer surrounds the contents of an egg
What effect will this have on big molecules?
Charged molecules?
Small or uncharged molecules?
Where might you expect to see a membrane in
biology?
So then, today’s challenges
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Figure out unknowns
Demonstrate what you know
Unknowns--What’s weird? Can you explain it?
A funny ‘liquid’
A funny solid
Demonstrating that you get it (x2)
Size Matters
Surface tension manifests
Hydrophobicity & your world
Heat helps (molecular movement, brownian motion)
Homework for next week
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Homework: Tao write-up, see handout
I think that is it but I will email right away if I
missed something.
Taking care of business
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The rubrics for all written assignments are
available on the main course page after you click
on your session (47).
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Pay attention to these, once you know what you
are being graded on, your work will become
much more focused.