To continue

Recall: In our study of biology We are considering what I call: LIVING SYSTEMS Highly organized systems of Matter and Energy

In our discussions then, we must Consider the relation of CHEMISTRY to the patterns and processes of LIVING SYSTEMS

The processes of chemisty are actually rather straightforward…

Here is chemistry in action!

But…what have we here?

We will end the semester with this, the Universe’s most complex chemical structure, and the “secret of life.” It’s DNA

But the chemistry of a l.s. requires us to consider certain ELEMENTS and their Chemical interactions

Here are most of the elements!

But a l.s. does not concern itself with every one of the approximately 90 naturally occurring elements…

Not this one…

This one…

Carbon, ol’ #6, is the “element of life,” and life is based on the Chemistry of Carbon

So why IS CARBON and its chemistry the basis of Living Systems?

But, then, what is chemistry?

Let’s pause a moment and ask a question…

The Purpose of Life is: a. to use matter and energy b. to survive and reproduce c. to understand the Universe d. to use chemical reactions

The Purpose of Life is: a. to use matter and energy b. to survive and reproduce c. to understand the Universe d. to use chemical reactions

But what was that we were saying about CHEMISTRY?

We are talking about SPONCH and the “Big C”

I’m a Woodchuck, and I’m full of SPONCH!

SPONCH? The major ELEMENTS found In Living Systems: Sulfur, Phosphorus, Oxygen Nitrogen, Carbon, Hydrogen

In order of abundance: Hydrogen Oxygen (A lot of H 2 O in a l.s.) Carbon Nitrogen Phosphorus Sulfur

SPONCH and some pals in a l.s.

Quick tour of Chemistry…

You know all about this, don’t you?

ISOTOPES—we’ll meet some of these later. Distinguish from ISOMERS, which we’ll meet today.

Although there is only a handful of different kinds of ELEMENTS in a living system, There are millions of kinds of MOLECULES

Let’s go from ATOMS to MOLECULES via a CHEMICAL REACTION

This one

Hydrogen plus oxygen…

What’s that “Delta G” thingy? It’s the “energy part” of a chemical reaction

A Chemical Reaction Involves the Making or Breaking of bonds, which are Electron Relations Between atoms

A Bond

Those bonds were COVALENT BONDS, (shared pairs of electrons) but there are other kinds of bonds that we can see in some molecules. In particular, Water illustrates the kind of bond called a HYDROGEN BOND

And water is also involved in the chemical condition that we call pH

Let’s pause for a moment…

A molecule is two or more atoms held together by a/an: a. exergonic relation b. chemical bond c. nuclear reaction d. elemental action

A molecule is two or more atoms held together by a/an: a. exergonic relation b. chemical bond c. nuclear reaction d. elemental action

When we look at living systems, from atom to organism, we can view it in terms of Levels of Structure

NIBMSEITLOE… Life has evolved chemically, as well as structurally, and all the chemical evolution is based on the chemistry of Carbon Molecules

Carbon molecules doing living things!

This is a fossil leaf, and the dark material

Is the carbon that made up its organic molecules…

The key element is Carbon

CARBON, Hooray!

Elemental Carbon as SOOT

Elemental Carbon As GRAPHITE

Elemental Carbon as DIAMOND

But we are interested in CARBON Which is in the form of ORGANIC MOLECULES

Here is a collection of a Variety of both Inorganic and Organic Molecules

And how do we build the thousands of different organic molecules that we find in any living system?

I call it “building the Chemical Cathedral”

But METABOLISM consists of TWO parts: ANABOLISM—the “building up” of large molecules from smaller ones. But also there is CATABOLISM, the breakdown of larger molecules into smaller ones.

The breakdown process…

Hydrolysis is DOWNHILL towards less structure, and the Universe favors processes like this over those in the direction of more structure

Let’s begin to look at building up and breaking down in relation to one of our classes of Organic Molecules, CARBOHYDRATES

The Basic Carbohydrate (for our purposes) Is a hexose, A monosaccharide, A simple sugar… GLUCOSE

But subtle differences in structure (ISOMERS) can produce sugars of different types

And there are other kinds of Sugars than Hexoses [6C] We can find: Trioses [3C] Pentoses [5C]

Let’s do a little “Cathedral Building”

We call this dehydration synthesis

So why IS CARBON and its chemistry the basis of Living Systems?

But, then, what is chemistry?

The Purpose of Life is: a. to use matter and energy b. to survive and reproduce c. to understand the Universe d. to use chemical reactions

The Purpose of Life is: a. to use matter and energy b. to survive and reproduce c. to understand the Universe d. to use chemical reactions

To be continued…