1. Molecules of Life
All living things are made up of four classes of large molecules: Carbohydrates, lipids, proteins, and nucleic acids.
Macromolecules are large molecules composed of thousands of covalently connected atoms.
Structure of the molecule affects its function.

2. Macromolecules are polymers built from monomers
Polymer- long molecule consisting of many similar building blocks
The small building blocks are called monomers.
Carbohydrates, Proteins, and Nucleic acids are polymers.

3. Building and Breaking down Polymers
A dehydration reaction occurs when two monomers bond together.
Loss of a water molecule.
Polymers are broken apart by hydrolysis.
Addition of a water molecule

4. (a) Dehydration reaction: synthesizing a polymer
Short polymer
Unlinked monomer
Dehydration removes a water molecule, forming a new bond.
Longer polymer
(b) Hydrolysis: breaking down a polymer
Hydrolysis adds a water molecule, breaking a bond. 1 2 3 4

5. Carbohydrates Serve as fuel and building material
Include sugars and the polymers of sugars.
Simplest are called monosaccharides (single sugars)
Classified by location of the C=O and number of carbons
Carbohydrate macromolecules are polysaccharides
Disaccharides- two sugar monomers linked.

6. Carbohydrates Store Energy
Starch- a storage polysaccharide of plants, consists of glucose molecules.
Simplest form is amylose
Found in the chloroplasts
Glycogen- is a storage molecule in animals
Mainly in muscle cells

7. Carbohydrates Provide Structure
Cellulose- major component of the tough wall of plant cells
Chitin- found in the exoskeleton of arthropods and supports the cell walls of many fungi

8. Lipids Hydrophobic molecules that do not form polymers.
Hydrophobic = Water fearing
Consist mostly of hydrocarbons, which form nonpolar covalent bonds
This group consists of:
Fats
Phospholipids
Steroids

9. Fats
Fats are constructed from two types of smaller molecules: glycerol and fatty acids
Glycerol- Three-carbon alcohol with a hydroxyl group on each carbon
Fatty acid- carboxyl group attached to a long carbon skeleton

10. Fatty acid (in this case, palmitic acid)
Figure 5.10
Fatty acid (in this case, palmitic acid)
Glycerol
(a) One of three dehydration reactions in the synthesis of a fat
Ester linkage
Figure 5.10 The synthesis and structure of a fat, or triacylglycerol.
(b) Fat molecule (triacylglycerol)

11. Two Kinds of Fats
Saturated Fatty acids- Have the maximum number of hydrogen atoms possible and no double bonds
Unsaturated fatty acids- Have one or more double bonds
Fats store energy and are stored in adipose cells

12. Phospholipids
Two fatty acids and a phosphate group are attached to glycerol
Fatty acid tails are hydrophobic
Phosphate group and attachments for hydrophilic head

13. Formation of Bilayers When in water, these phospholipids form bilayers
Hydrophilic heads face water
Hydrophobic tails face each other
Found in cell membranes

14. Nucleic Acids
Nucleic acids store, transmit, and help express hereditary information.
DNA and RNA are examples of nucleic acids.
Made of monomers called nucleotides
Nucleotides are made up of a nitrogenous base, a sugar, and a phosphate group

15. DNA and RNA RNA molecules are single polynucleotide chains
Single stranded
DNA molecules have two polynucleotides spiraled in a double helix
Each strand runs antiparallel (opposite directions)
One DNA molecule can include many genes

17. Proteins
Includes a diversity of structures that have a wide range of functions.
Functions include:
Structural support
Storage
Transport
Cellular communications
Movement
Defense against foreign substances

18. Proteins Proteins consist of one or more polypeptides
Polypeptides are unbranched polymers built from the 20 amino acids that are linked by peptide bonds
Amino Acids are the monomers of proteins
Amino Acids are organic molecules with carboxyl and amino groups
Differ in their properties because of the differing side chains

20. Protein Structure
A functional protein consists of one or more polypeptides twisted, folded, and coiled into a unique shape.
The sequence of Amino Acids determines the structure, and that determines its function

21. Four Levels of Structure
The primary structure- its unique sequence of amino acids (Information in genes)
Secondary structure- consists of coils and folds in the polypeptide chain
Alpha helix and Beta pleated sheet
Tertiary structure is determined by interactions among various side chains
Quaternary structure results when a protein consists of multiple polypeptide chains

22. Animation
Protein Structure Animation (Resources Page)

23. Loss of Structure
Alterations in pH, temperature, salt concentration can cause a protein to unravel.
The loss of a protein’s structure is called denaturation.
Once denatured, the protein is inactive.

24. Enzymes
Enzymes are a type of protein that acts as a catalyst and speeds up chemical reactions.
Enzymes can perform their functions repeatedly.
Without enzymes, many of life’s processes would not be possible.

26. Bozeman Video
Molecules of Life- Bozeman Science (Resources Page)