Life Substances

1. Life Substances The Role of Carbon

2. Cells • Composed of 70-95% water the rest is made up of CARBON based compounds • Molecules that contain CARBON are said to be ORGANIC • Examples: methane, carbon dioxide, proteins

3. Carbon’s Reactivity • Carbon (C) appears in the 2nd row of the periodic table and has 4 bonding electrons in its valence shell. • Can form 4 bonds with other atoms (each bond consisting of one of the carbon’s electrons and one of the bonding atom’s electrons) • These bonds form a tetrahedron • A pyramid with a spike at the top and angles of 109°

4. Hydrocarbons • Simplest organic compound • Gets its name because it only contains hydrogen and carbon atoms • Examples: • Methane • Ethane • Hexane • Isohexane • Cyclohexane

5. Carbon Bonds There appears to be no limit to the number of different structures carbon can form… Keep in mind  carbon can form 4 bonds. So, as the number of bonds between carbon atoms increases, the number of hydrogen atoms decreases

6. Simple Hydrocarbons • Alkanes  carbon-carbon (single bond) • Chemical formula: CnH2n+2 • All enter combustion reactions with oxygen to produce CO2 and water vapor • They are flammable! • Alkenes  carbon = carbon (double bond) • Chemical formula: CnH2n • Alkynes  carbon carbon=carbon (triple bond) • Chemical formula: CnH2n-2

7. Isomers • Structures that have identical chemical formulas but their structural formulas are different • Different chemical properties too • Because carbon can bond in so many ways, a single molecule can have different bonding configurations

8. two substances having the same molecular formula but different physical and chemical properties because the arrangement of their component atoms is different. Structural Isomers

9. A chemical compound having the same molecular formula as another but a different geometric configuration, as when atoms or groups of atoms are attached in different spatial arrangements on either side of a bond or a ring. Geometric Isomers

10. Two substances having the same molecular formula but they are mirror images of one another. Enantiomers

11. What type of isomer are these?

12. Functional Groups • Hydroxyl – OH • These are referred to as alcohols • The existence of a functional group completely changes the chemical properties of a molecule • Example: • Ethane (2C alkane): gas at room temp • Ethanol (2C alcohol): liquid at room temp • Common drinking alcohol  active ingredient in “alcoholic” beverages such as beer and wine

13. CH2OH O H H H OH H OH HO H OH Carbohydrates energymolecules

14. Carbohydrates

15. sugar sugar sugar sugar sugar sugar sugar sugar Carbohydrates • Carbohydrates are composed of C, H, O carbo - hydr - ate General formula: CH2O (CH2O)x C6H12O6 • Function: • energy u energy storage • raw materials u structural materials • Monomer (building block): sugars • ex: sugars, starches, cellulose

16. H O C CH2OH CH2OH C OH O H H O H H H OH H OH H C H HO OH HO HO H H H OH OH H Glyceraldehyde Glucose Ribose Sugars • Most names for sugars end in -ose • Classified by number of carbons • 6C = hexose (glucose) • 5C = pentose (ribose) • 3C = triose (glyceraldehyde) 6 5 3

17. Sugar structure 5C & 6C sugars form rings in solution Where do you find solutions? In cells! Carbons are numbered

18. Numbered carbons C 6' C O 5' C C 4' 1' energy stored in C-C bonds C C 3' 2'

19. CH2OH O H H H OH H OH HO H OH Glucose Simple & complex sugars • Monosaccharides • simple 1 monomer sugars • glucose • Disaccharides • 2 monomers • sucrose • Polysaccharides • large polymers • starch

20. Dehydration Synthesis=Polymerization • Anabolic reaction • Produces polymer • Monomer + Monomer  Polymer + Water 2 Monomers Bond= Polymer Remove H2O

21. Building sugars • Dehydration synthesis monosaccharides disaccharide | glucose | glucose | maltose glycosidic linkage

22. Building sugars • Synthesis monosaccharides disaccharide | glucose | fructose | sucrose (table sugar) Let’s go to the videotape!

23. Hydrolysis • Catabolic reaction • Produces monomers • Ex) Polysaccharides monosaccharides • Polymer + Water  Monomer + Monomer Separate polymer into: 2 monomers Add H2O

24. Polysaccharides • Polymers of sugars • costs little energy to build • easily reversible = release energy • Function: • energy storage • starch (plants) • glycogen (animals) • structure = building materials • cellulose (plants) • chitin (arthropods & fungi)

25. Linear vs. branched polysaccharides starch (plant) What doesbranching do? energystorage glycogen (animal) Let’s go to the videotape!

26. Polysaccharide diversity • Molecular structure determines function in starch in cellulose • isomers of glucose • structure determines function…

27. enzyme enzyme Digesting starch vs. cellulose starcheasy todigest cellulosehard todigest

28. Cellulose • Most abundant organic compound on Earth • herbivores can digest cellulose • most carnivores cannot digest cellulose • that’s why they eat meat to get their energy & nutrients • cellulose = roughage BIG DEAL!Who can liveon this stuff?!

29. Cow can digest cellulose well; no need to eat other sugars Gorilla can’t digest cellulose well; must add another sugar source, like fruit to diet

30. Helpful bacteria • How can cows digest cellulose? • bacteria live in their gut & help digest cellulose-rich (grass) meals

31. Let’s build some Carbohydrates!