Download Monomers are the

Init by Daniel R. Barnes 6/10/2010
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A bunch of monomer molecules linked
together in a row form a chain-like
molecule called a “polymer”.
monomer
monomer
monomer
monomer
monomer
monomer
monomer
monomer
monomer
SWBAT . . .
. . . explain how polymers
can be built out of
monomers.
silicone rubber
Silicone rubber is a long, long molecule with many uses.
o-rings
silicone sealant (“caulk”)
medical tubing
silicone rubber
Silicone rubber is a “polymer”. It’s
a long, chain-like molecule made of
repeating subunits.
Those subunits are called
“monomers”. Monomers are the
“links” in the polymer “chain”.
NOTE: Silicone rubber is an unusual polymer in that its
backbone is made of silicon and oxygen and contains no
carbon. (There are carbon-containing bits sticking off of the
backbone, but no carbon in the backbone itself.)
silicone rubber
CH3
O
Si
CH3
Q: What is the repeating subunit in silicone rubber?
Do you see the little “n”?
The “n” means that something is repeating over and over
again an unknown number of times – probably a lot of times.
It looks like the repeating subunit is just “SiO”.
However, the formula on the right is a “skeletal” formula, so
you have to imagine a CH3 group at the end of each of the two
sticks sticking up and down from the Si atom.
silicone rubber
CH3
O
Si
CH3
Q: What is the repeating subunit in silicone rubber?
It looks like the thing that keeps repeating over and over
again is . . . Si(CH3)2O
A long, chainlike molecule made of repeating subunits is
called a “polymer”.
The subunit that repeats over and over again is called a
“monomer”.
Such “repeating subunits”
are called “monomers”.
CH2CH(Cl)CH2CH(Cl)CH2CH(Cl)CH2CH(Cl)CH2CH(Cl)
SWBAT . . .
. . . describe what complex
carbohydrates, nucleic
acids, and proteins are
made of.
There are many other man-made polymers that are very
handy for making lots of useful things. However, your grade
depends more on knowing about the biological polymers
found in your body and other organisms.
Monomer
Polymer
amino acids
(20 main kinds)
proteins
(including enzymes)
simple carbohydrates complex carbohydrates
(sugars like glucose)
(starch, cellulose)
nucleotides
(A, T [or U], G, C)
A—T—C—G—G—A—T—C
T—A—G—C—C—T—A—G
nucleic acids
(DNA, mRNA, tRNA)
Glucose, like many
sugars, can go back and
forth between the ring
form and the linear form
shown below.
This is glucose.
It’s a kind of sugar.
The version shown above
is the ring version.
Notice that a
sugar molecule
includes a bunch
of carbon atoms.
Usually, a carbon
atom in a sugar
molecule has an H
atom stuck to it
and an OH stuck
to it also.
H + OH = H2O, so
that’s why sugars
are called . . .
“carbohydrates.”
glucose
galactose
Sugars are known as
“simple carbohydrates”
because they’re made
of only one sugar
molecule each.
fructose
ribose
amylose
Starch is a clean-burning
complex carbohydrate that
makes great fuel for athletes.
Plants and animals both use
it as a way to store energy.
You can digest it with an
enzyme in your saliva.
Starch and cellulose are “complex carbohydrates” because
they are polymers made of many sugar monomers linked
together in a row.
cellulose
We don’t have an enzyme for
digesting cellulose, but germs
living in the guts of termites and
cows can make one. To us, it is
“dietary fiber” or “roughage”. It
is the main structural
compound in plants.
amylose
Starch and cellulose are “complex carbohydrates” because
they are polymers made of many sugar monomers linked
together in a row.
cellulose
= sugar = simple carbohydrate
= monosaccharide
Ex: glucose, fructose, galactose, dextrose,
ribose, deoxyribose
= sugar = simple carbohydrate
= disaccharide
Ex: sucrose, lactose
etc. 
= complex carbohydrate
= polysaccharide
Ex: starch, cellulose
COMPLEX CARBOHYDRATES
Starch
= digestible by humans
Cellulose = NOT digestible by humans
They’re both better for you than sugar (simple carbs).
Q: What monomer are complex carbohydrates made out of?
A: simple carbohydrates = sugars = monosaccharides
Q: What do the names of all carbohydrates end with?
A: “- ose”
Q: Compare and contrast starch and cellulose.
Psych! Under construction . . .
SWBAT . . .
. . . describe protein synthesis
and explain how amino acid
sequence determines a
protein’s properties
amino
acid
amino
acid
amino
acid
amino
acid
amino
acid
Protein is a polymer made of amino acid monomers.
amino
amino
acid
amino
amino
acid
acid
acid
amino
amino
acid
amino
acid
acid
There are 20
different amino
acids that are
included in the
proteins made by
your ribosomes
based on mRNA
sent by your DNA.
http://www.johnkyrk.com/aminoacid.html
Glycine is the
simplest amino acid.
acid
amino
The “R” group is different
in the 20 main amino acids,
but all the other parts are
the same. In glycine, the
“R” group is just a simple
hydrogen atom.
Aspartic acid is an
amino acid that’s
extra acidic.
It has a carboxylic acid
group in the place that
all amino acids do.
Is that COOH
with you?
C
C
But it also has an
second carboxylic acid
group in its “R” chain.
Wait. You can’t
recognize them? Here.
Let me add a letter . . .
Lysine is an amino
“acid”, but it has an
extra amino group on
its “R” chain, so it’s
more alkaline than most
amino acids.
Lysine is extra basic.
Threonine’s R group
loves water.
+
Threonine’s R chain is
polar because the O
atom in the OH is so
good at hogging
electrons.
Leucine’s R group
doesn’t like water.
It’s not that it hates water. It
just has no particular
attraction for it.
Leucine’s R group is
made of nothing but
carbon and hydrogen . . .
just like oil.
So, of the 20 main amino acids, one might
classify them into four main types:
-
Amino acids with acidic side chains, which give
away H+ ions sometimes, ending up negative.
+
Amino acids with basic side chains, which accept
H+ ions sometimes, ending up positive.
+-
Amino acids with neutral side chains that have
polar covalent bonds in them.
Amino acids with neutral side chains that have
nothing but nonpolar bonds in them.
Of the above four kinds of amino acids,
only the last one doesn’t like water.
You may think that when a ribosome makes a protein chain
out of amino acids, the protein just kind of waves around in
the water, stretched out like an eel.
ribosome
However, the real story is that as soon as an amino acid is
added onto the growing protein chain, its electrical charges
start to make it move toward and away from various stuff.
Positive amino acids move
toward negative amino acids.
Positive amino acids move away
from other positive amino acids.
Water has polar
covalent bonds, so
other things that
have +’s & -’s in
them are attracted
to water.
Polar and charged
objects tend to be
hydrophilic. They
love water.
Therefore . . .
Polar and charged amino acids move toward the outside of
the protein, where they can be near the water that the protein
is surrounded by. Nonpolar amino acids hide in the middle.
Amino acid side chains move away from and toward various
things because of their electrical charge configurations.
Amino acid sequence determines what 3D shape a protein
strand will fold and wrinkle and crumple into.
Amino acid sequence determines which other chemicals will
tend to stick to the protein or drift away from the protein.
In these and other ways, amino acid sequence determines
how a protein will behave.
Depending upon its sequence of amino acids, a protein may
or may not be a good structural protein, like keratin.
Depending upon its sequence of amino acids, a protein may
or may not have a special chemical transportation function,
like hemoglobin.
Depending upon its sequence of amino acids, a protein may
or may not end up acting as a chemical messenger, like
insulin, the hormone diabetics have a problem with.
Depending upon its sequence of amino acids, a protein may
or may not have the magical ability to catalyze one or more
chemical reactions, making it an enzyme, like pepsin.