1. Molecules of Life The stuff we’re made of

2. Water The human body is mostly water –Lean muscle: 75% water –Blood: 83% water –Body fat: 25% water –Bone: 22% water All living organisms require water to live

3. Properties of Water Water is a polar molecule – Each atom has a partial charge –Molecule has zero net charge Polar molecules have special properties –Good solvents –Bond with each other (cohesion) –Take longer to heat and cool O HH δ - δ + O HH δ - δ + O HH δ - δ +

4. Partial charges on atoms, no net charge overall!

5. Water Trivia What occupies more volume – 8 oz of water at room temperature, or 8 oz of water at -10 F? IceLiquid

6. Properties of Water Water molecules are attracted to molecules of solid surfaces (adhesion) Adhesion allows water to move through very small pores or tubes against gravity (capillary action)

7. Carbon A carbon atom has 4 outer (valence) electrons – wants to make 4 bonds to be stable Carbon can bond with itself and many other elements Because it’s so friendly, carbon is present in all life on earth

8. Organic Molecules Any molecule containing carbon is called an organic molecule !! Except CO 2 !! Most organic molecules are arranged like chains –Each link is a monomer –A chain is a polymer –A large molecule made of a long chain or chains is a macro molecule

9. Types of Organic Molecules Carbohydrates Lipids Nucleic acids Proteins

10. Carbohydrates Molecules used for energy, made of C H O –Monosaccharide: a simple sugar (glucose, fructose, galactose) –Disaccharide: two monosaccharides bound together (sucrose aka table sugar) –Polysaccharide: 3 or more monosaccharides (starch is hundreds of glucose molecules bonded together)

11. Carbohydrates Glycogen stored in liver cells (red) Cellulose in plant cell walls (outer blue layer) Starch compartments in potato cells

12. Lipids Fatty compounds made of C H O, don’t interact with water (hydrophobic) –Cell membranes are composed two lipid layers, which keep water from crossing Lipids are polymers made up of fatty acid monomers –Fatty acids have oily “tails” and polar “heads” Non polar (Boo water!) Polar (Yay water!)

13. Lipid Layers Lipids in water will arrange themselves to hide their hydrophobic tails Cell membranes are composed of a phospholipid bi-layer What is a phospholipid?

14. Other Lipids Waxes Oils Steroids

15. Nucleic Acids The genetic material in any cell –Deoxyribonucleic acid (DNA) and Ribonucleic acid (RNA) –Polymer chains composed of a combination of 5 different monomers

16. Nucleic Acids The monomers are called nucleotides –Adenine, Cytosine, Guanine, Thymine (DNA only), Uracil (RNA only) –Bond in specific pairs –Adenine – Thymine (Uracil) –Guanine – Cytosine Nucleic acid polymers are millions of monomers long, wound in a double helix Helix unwinds during replication (copying)

17. DNA Trivia The DNA from a single human cell has a length of ~ 5.9 feet. The biggest cells are less than 0.1 inches across How can so much DNA fit in a cell?

18. Proteins Structural building blocks of cells in all tissues (not just muscle!) Polymers composed of 300 – 100k+ monomers Monomers are called amino acid There are 20 amino acids, many of which must come from your diet

19. Protein Structure Primary structure – the order of amino acids making up the polymer string Secondary structure – helixes and sheets of the polymer string folding on itself

20. Protein Structure Tertiary structure – globs of sheets and helixes folding around each other Quaternary Structure – individual proteins bound to each other to form a multi-protein unit with is own unique function

21. Hemoglobin carries oxygen in the blood

22. Actin fibers in skeletal muscle cells

23. Proteins make up the cell cytoskeleton

24. Enzymes to copy and repair DNA