Because carbon contains 4 electrons in its outer shell, it can pair in many ways with many different atoms in an “attempt” to fill its outer shell.

Carbon is the central atom of life.

Molecules of Life

Start with water, add lots of small carbon-containing molecules and …

How do you build a cell?

use these four major classes of biological molecules.

Monomers, Polymers and MacromoleculesMany biological molecules are macromolecules – very large.

Biological macromolecules are formed by linking together a set of building blocks (monomers) into long chains (a polymer).

CarbohydratesCarbohydrates are used for immediate energy and to create structures.

The building blocks for carbohydrates are simple sugars.

Three views of glucose, a common simple sugar.

Linking Simple Sugars – the First Step to a Polymer

A complex carbohydrate is a long-chain polymer made of simple sugars.

monosaccharides a disaccharide

Larger molecules form by a process called dehydration synthesis.

Some Familiar and Important Complex Carbohydrates

Note the way complex macromolecules are built by linking simple repeating units.

Carbohydrates are Central Players in Energy Production and Storage

Complex Carbohydrates Are Often Used to Create Structures

Cellulose is the most abundant macromolecule on earth – and you’re probably wearing it now.

Lipids are Hydrophobic Molecules That Exist In Three Primary Forms

Sterol

FatPhospholipid

Fats Are Made By Linking 3 Fatty Acid Chains to Glycerol, a Three Carbon Molecule

Space-filling model of a fat

A fatty acid

Molecular Structure of a Fat

Fats are Used in Energy Storage and Production

The Degree Of Saturation In A Fat Affects Its Physical And Health Properties

Where are the double bonds?

Cis and Trans Unsaturated Fats

all cis polyunsaturated“Good”

Omega-3-fatty acids

mono- and poly-unsaturated

saturated

trans

“Bad”

At a Store Near You

Beginning January 1, 2006, the FDA required that the amount of trans fat be listed on all food labels.

The new line showing levels of trans fat

Sterols

Note the four ring structure common to all sterols.

Sterols are: 1) essential membrane components and 2) form many hormones.

Sterols As Hormones

Estrogen, testosterone, progesterone, and corticosteriods (cortisol) are all steroid hormones.

Sterols As Hormones

“Designer steroids” are major sporting news where they have been used illegally in track and field, baseball, football and countless other sports.

A heavily muscled Linford Christie who was disqualified from international competition after testing positive for a banned steroid.

Phospholipids are Building Blocks of Cellular Membranes

The hydrophilic (water-loving) head group and hydrophobic (water-fearing) tails are the keys to phospholipid function.

Hydrophilic Head Group And Hydrophobic Tails Are The Keys To Phospholipid Function

Phospholipids Form Double-Layered Biological Membranes

Protein

Proteins are key elements of life.

Remember the principle - structure determines function.

Since proteins are the key players of the cell, it follows that protein structure determines cell function.

Some of the Many Different Functions of Proteins

Strands of the Protein Keratin Create Hair

Proteins are Linear Chains of Linked Amino Acids

A Common Thread and a Unique Identity

Amino Acids, Peptide Bonds, Polypeptide = Protein

Peptide bonds

Proteins are linear chains of 20 different building blocks called amino acids.

Amino acids are linked by peptide bonds – a form of covalent bond.

Proteins are folded structures whose shape (and therefore function) depends on amino acid sequence.

Nucleic Acids

There are two kinds of nucleic acids, DNA and RNA. Both are involved in the storage and flow of information from gene to gene product.

DNA

Recently, we’ve learned that RNA also plays important regulatory roles.

Nucleotides Are the Monomers That Create Polymers of DNA and RNA