Init by Daniel R. Barnes 6/10/2010

WARNING: This presentation includes graphical and other elements taken from the world wide web without the permission of their copyright owners. Do not copy or distribute this presentation. Its very existence may be illegal.

WARNING: The author of this presentation makes shameless and frequent use of wikipedia as an information source. Take it with the grain of salt that this demands.

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.

silicone sealant (“caulk”)

o-rings

medical tubing

silicone rubber

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 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”.

silicone rubber

Q: What is the repeating subunit in silicone rubber?

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.

SiO

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.

CH3

CH3

silicone rubber

Q: What is the repeating subunit in silicone rubber?

SiO

It looks like the thing that keeps repeating over and over again is . . . Si(CH3)2O

CH3

A long, chainlike molecule made of repeating subunits is called a “polymer”.

The subunit that repeats over and over again is called a “monomer”.

CH3

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.

Monomer Polymer

proteins(including enzymes)

amino acids

complex carbohydrates(starch, cellulose)

simple carbohydrates(sugars like glucose)

nucleic acids(DNA, mRNA, tRNA)(A, T [or U], G, C)

(20 main kinds)

A—T—C—G—G—A—T—C

nucleotides

T—A—G—C—C—T—A—G

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.

This is glucose.

It’s a kind of sugar.

The version shown above is the ring version.

Glucose, like many sugars, can go back and forth between the ring form and the linear form shown below.

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

fructose

galactose

ribose

Sugars are known as “simple carbohydrates” because they’re made

of only one sugar molecule each.

amylose

cellulose

Starch and cellulose are “complex carbohydrates” because they are polymers made of many sugar monomers linked together in a row.

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.

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

cellulose

Starch and cellulose are “complex carbohydrates” because they are polymers made of many sugar monomers linked together in a row.

= sugar = simple carbohydrate = monosaccharideEx: glucose, fructose, galactose, dextrose, ribose, deoxyribose

= complex carbohydrate= polysaccharideEx: starch, cellulose

= sugar = simple carbohydrate = disaccharideEx: sucrose, lactose

etc.

Starch

Cellulose

= digestible by humans

= NOT digestible by humans

COMPLEX CARBOHYDRATES

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

aminoacid

aminoacid

aminoacid amino

acid

aminoacid

aminoacid

aminoacid

aminoacid

aminoacid

aminoacidamino

acidaminoacid

Protein is a polymer made of amino acid monomers.

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.

aminoacid

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.

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 . . .

CC

Is that COOH with you?

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 chain is polar because the O atom in the OH is so good at hogging electrons.

+

Threonine’s R group loves water.

Leucine’s R group doesn’t like water.

Leucine’s R group is made of nothing but carbon and hydrogen . . . just like oil.

It’s not that it hates water. It just has no particular attraction for it.

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.

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.

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 . . .

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.

In these and other ways, amino acid sequence determines how a protein will behave.

Amino acid sequence determines which other chemicals will tend to stick to the protein or drift away from the protein.

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 have the magical ability to catalyze one or more chemical reactions, making it an enzyme, like pepsin.

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.