1. Carbohydrates and Lipids Section 1-3

2. Macromolecules Macromolecules are huge molecules made up of smaller subunits Macromolecules are polymers of single subunits known as monomers There are 4 classes of biological macromolecules Carbohydrates Lipids Nucleic acids Proteins

3. Condensation/Dehydration Reactions AKA dehydration synthesis reactions Reactions in which two or more monomers are linked together and one water molecule is lost in the process One monomer contributes the –OH while the other contributes the –H The bond forms where the hydroxyl and hydrogen are removed The cell must expend large amounts of energy to complete these reactions, which only occur in the presence of enzymes

4. Condensation/Dehydration Reactions

5. Hydrolysis Reactions “hydro” = water “lysis” = break Reactions by which a polymer is broken down into monomers with the addition of a water molecule One monomer gets the –OH while the other gets the –H Does not require much energy and can happen with or without enzymes

6. Hydrolysis Reactions

7. Carbohydrates

8. Monosaccharides General formula CH 2 O General Structure Contains a carbonyl group at either the end or in the middle Contains multiple hydroxyl groups Usually forms ring structure when dissolved in water

9. Categorizing Monosaccharides Placement of the carbonyl group At the end of the molecule= aldose In the middle of the structure = ketose Number of carbons

10. Functions of Monosaccharides Major source of fuel for cellular work Carbon skeletons serve as the raw material for other small organic molecules

11. Disaccharides Two or more monosaccharides joined together by a glycosidic linkage Glyscosidic linkage- the bond formed between two monosaccharides during a dehydration reaction “Glyco”= sugar attached Examples: Matose= glucose + glucose Sucrose= glucose + fructose Lactose= glucose + galactose

12. Polysaccharides Macromolecules of many monosaccharides joined together Structure and function is determined by the monomer it contains and the position of the glycosidic linkages Polysaccharides are used for storage and structure in organisms

13. Storage Polysaccharides- Starch Plant storage Consists of all glucose arranged by linkages that make the polymer helical Stored in plastids of plants as a stockpile of glucose Can be broken down quickly by hydrolysis reaction when needed

14. Storage Polysaccharide- Glycogen Animal storage Polymer of glucose that is extensively branched Stored in the liver and muscle cells of animals Hydrolysis of glycogen releases glucose Short term storage reserves are depleted quickly (in humans 24 hours) if not replenished by consuming food

15. Storage Polysaccharides

16. Structural Polysaccharides- Cellulose Plant structure Polymer of glucose that is mostly straight and never branched Each strand is hydrogen bonded to the next and grouped in microfibrils making it extremely strong Found in the cell wall of plant cells Not able to be digested without special enzymes (humans don’t have them)

17. Cellulose

18. Structural Polysaccharide- Animals and Fungi Structural carbohydrate of animals and fungi Makes up the cell walls of fungi and when combined with calcium carbonate the exoskeleton of arthropods

19. Lipids

20. General Characteristics Not true polymers Form groups of molecules due to hydrophobic interactions Functions include Long term energy storage Membrane structure Cellular and long distance signaling

21. Saturated vs. Unsaturated Lipids

22. Saturated Lipids Contain fatty acids chains that are completely saturated with carbon There are no double bonds anywhere within the fatty acid chain They are able to stack nicely, side by side Solid at room temperature Animal fat

23. Unsaturated Lipids Contains one or more double bonds in the carbon chain Causes kinks in the chain that allows spaces between one lipid and the next Liquid at room temperature Plant and fish oils

24. Saturated vs. Unsaturated Lipids

25. Fats/Triglycerides 1 glycerol- a 3 carbon alcohol with a hydroxyl group attached to each carbon 3 fatty acids- hydrocarbons with a carboxyl group at the end

26. Fats/Triglycerides Ester linkages- bonds that connect the fatty acids to the glycerol Occurs via dehydration reactions Occurs between the hydroxyl group of the glycerol and the carbonyl group of the fatty acid Function: long term energy storage

27. Phospholipids

28. Glycerol connected to: Two fatty acid tails- hydrophobic One phosphate group- negatively charged and hydrophyllic When placed in water the phospholipids self-assemble into bilayers Phospholipids make the major component of plasma membranes

29. Steroids Composed of 4 fused rings Most steroids are synthesized from cholesterol, a common component in the cell membrane Can serve as short distance (attached to the membrane) or long distance (hormone) cellular signals