NOTES 8 – Polymers & Biochemical Compounds

1. NOTES 8 – Polymers & Biochemical Compounds

2. What is a polymer? • Polymer – a large molecule formed by linking together many small molecules (monomers) • Monomers – small molecules that make up polymers when linked together • Ex. Polyethene (a type of plastic) • The prefix poly means “many” • The suffix ethene is an alkene with the formula C2H4 • Polyethene = “many ethenes”

3. Natural vs. Man-made Polymers • Natural polymers are large organic molecules formed by living organisms • Ex. Wood (cellulose), cotton, wool, starch, protein, DNA • Man-made polymers are created from natural polymers • Ex. Plastics – flexible and easily molded • Ex. Fibers – form long, thin strands (nylon, etc.)

4. Polymer Structure Determines Properties • Polymer molecules are like long, thin chains • A piece of plastic is made of billions of these chains • If the polymer chains are tangled but not connected, the polymer will be flexible • Ex. Plastic milk jug (polyethene) - If the plastic is crushed, it does not return to its original shape

5. Polymer Structure Determines Properties • If the polymer chains are connected, or cross-linked, the polymer can stretch and return to its original shape • Elasticity – the ability of a polymer to return to its original shape when stretched • Ex. Rubber

6. What are biochemical compounds? • Biochemical compound – a naturally occurring organic compound • Contains carbon • Has a molecular structure • Produced by living organisms • Essential to life • Some are huge polymers • Remains change over time into fossil fuels (coal, oil, natural gas) • Ex. Carbohydrates, proteins, DNA, lipids (fats & oils)

7. Carbohydrates • Used for cell energy and building material • Produced by plants (photosynthesis) • Can be small molecules • Ex. glucose and fructose (simple sugars) • Can be large polymers • Ex. Starch is a large plant polymer made of many linked glucose monomers • Ex. Glycogen is a large animal polymer made of many linked glucose monomers

8. Cellulose is the main ingredient in plant cell walls and is the most abundant organic compound on Earth - plants produce roughly 100 billion tons of cellulose per year! Paper and cotton are almost 100% cellulose Cows and termites have cellulose-digesting microorganisms living in their digestive systems that enable them to break down cellulose-rich foods like grass (cows) and wood (termites) – you don’t have any! Did you know?

9. Foods That Contain Carbohydrates • Wheat, pasta, bread, rice, potato, vegetables, fruits, honey • Your body breaks down all carbs into glucose, which is used by your cells or stored as glycogen (a polymer) in your liver until it is needed

10. Proteins • Large polymers made out of many linked amino acid monomers • There are 20 unique amino acid monomers • Different amino acid combinations make different proteins • Make up structures of organisms • Speed up chemical reactions • Act as cell to cell messengers • Ex. Insulin – controls blood glucose levels • Ex. Lactase – digests milk sugar (lactose)

11. Foods That Contain Proteins • Meat, dairy products, eggs, beans, nuts • When you eat foods that contain proteins, your digestive system breaks down the proteins into individual amino acids • Your cells bond the amino acids in a different order to form whatever protein your body needs

12. DNA – Deoxyribonucleic Acid • Large polymer made out of many linked nucleotide monomers • Has double helix structure (twisted ladder) • Found in most living cells • Carries genetic code (protein-building instructions) • Determines organism characteristics • Is able to be copied exactly and passed from one generation to the next