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. Did you know?
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!

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