THE STRUCTURE AND FUNCTION OF LARGE BIOLOGICAL MOLECULES

1. THE STRUCTURE AND FUNCTION OF LARGE BIOLOGICAL MOLECULES Chapter 05

2. MACROMOLECULES ARE POLYMERS, BUILT FROM MONOMERS What are polymers? What are monomers?

3. MACROMOLECULES What is a polymer? Poly = many; meris = part. A polymer is a large molecule consisting of many smaller or identical sub-units linked by covalent bonds What is a monomer? A monomer is a sub-unit of a polymer; a repeating unit that serves as building blocks of a polymer

4. SYNTHESIS & BREAKDOWN OF POLYMERS How are covalent linkages between monomers formed in the creation of organic polymers? Condensation or dehydration synthesis reactions. Monomers are covalently linked to one another through the removal of water. One monomer provides a hydroxyl group (-OH), while the other monomer provides a hydrogen (-H) The dehydration process is facilitated by enzymes and requires energy

5. DEHYDRATION REACTION

6. SYNTHESIS & BREAKDOWN OF POLYMERS What is hydrolysis? Hydro = water; lysis = break Polymers are broken down into monomers by the addition of water molecules A hydrogen from the water attaches to one monomer and a hydroxyl group attaches to the adjacent monomer Hydrolysis requires enzymes and releases energy

7. HYDROLYSIS

8. WHAT ARE THE FOUR TYPES OF LARGE BIOLOGICAL MOLECULES? Carbohydrates Lipids Proteins Nucleic Acids

9. CARBOHYDRATES

10. MONOSACCHARIDEmonos = single, sachar = sugar Generally some multiple of the unit of CH2O Sugars contain Carbonyl group Multiple Hydroxyl groups carbo - hydr - ate H2O)x C6H12O6

11. HOW DO YOU CLASSIFY SUGARS?

12. 1. PLACEMENT OF THE CARBONYL GROUP Sugars with their carbonyl group at the end of the carbon skeleton are an aldose (aldehyde sugar) Sugars with their carbonyl group within the carbon skeleton are a ketose (ketone sugar) Most sugar names end with “ose”

13. #2 – THE SIZE OF THE CARBON SKELETON Size ranges from 3-7 carbons long Classified by number of carbons 6C = hexose (glucose) 5C = pentose (ribose) 3C = triose (glyceraldehyde)

14. #3 – THE SPATIAL ARRANGEMENTS OR THEIR PARTS AROUND ASYMMETRIC CARBONS Glucose versus galactose is one example Due to this small difference these two sugars have distinctly different shapes and behaviors

15. IN AQUEOUS SOLUTION MOST SIMPLE SUGARS FORM RINGS

16. CARBONS ARE NUMBERED FOR EASY REFERENCE

17. WHAT ARE THE TWO MAJOR ROLES OF MONOSACCHARIDES? Major nutrient for the cells – a major fuel for cellular work Their carbon skeletons serve as raw material for the synthesis of other small organic molecules, such as amino acids and fatty acids

18. WHAT IS A DISACCHARIDE? Two monosaccharides joined by glycosidic linkage

19. EXAMPLES OF DISACHARIDES?

20. WHAT IS A POLYSACCHARIDE? They are macromolecules, polymers with a few hundred to a few thousand monosaccharides joined by glyposidic linkages

21. WHAT ARE POLYSACCHARIDES USED FOR? Storage of sugar Building material for structures that protect the cell or whole organism What determines the architecture and function of the polysaccharide? Its type of sugar monomers The position of its glycosidic linkages

22. STORAGE POLYSACCHARIDES Plants form what polysaccharide to store their sugar? Animals form what polysaccharide to store their sugar?

23. STRUCTURAL POLYSACCHARIDES What is the polysaccharide, made by plants, thatis the most common organic molecule on the planet? What is the polysaccharide produced by insects to form their exoskeletons?

24. HOW ARE STARCH AND CELLULOSE SIMILAR? HOW ARE THEY DIFFERENT?

25. STARCH VERSUS CELLULOSE Similar – like starch, cellulose is a polymer of glucose Different – the glyposidic linkages are different, causing the glycogen to arrange themselves differently This cause cellulose to be straight (starch is helical), which allow its hydroxyl groups to interact and form strong strands What is cellulose’s function? Forms the the cell walls of plants that give their cells some rigidity

27. WHAT PURPOSE DOES CELLULOSE PLAY IN THE HUMAN DIET? It is not digestible by most organisms, including humans It is the fiber in our diet – stimulates the digestive tract to secrete mucus which aids in the smooth passage of food Found in most fruits, vegetables, and whole grains

28. LIPIDS

29. WHAT ARE LIPIDS? NOT true polymers – the are made of smaller units, but NOT repeating chains NOT generally big enough to be considered macromolecules Hydrophobic – they mix poorly, if at all, with water Mostly composed of hydrocarbon regions They include fats, phospholipids, steroids, waxes, and certain pigments Lipids are NOT … Lipids are …

30. FATS Fats are NOT polymers but they are made from a few smaller molecules What are the two types of molecules that make up fat? How many of each molecule?

31. FATS ARE COMPOSED OF … 1 - GLYCEROL 3 – FATTY ACIDS

32. A TYPICAL FAT OR TRIACYLGLYCEROL OR TRIGLYCERIDE

33. FATTY ACIDS VARY IN LENGTH AND NUMBER AND LOCATION OF DOUBLE BONDS – THUS FATS CAN BE CLASSIFIED AS EITHER … NO double bonds between carbon atoms Thus saturated with hydrogen Molecule is flexible Solid at room temperature Animal fats Less desirable, because harder to digest One or more double bonds by the removal of hydrogen Double bonds create “kinks” – areas that are not flexible Liquid at room temperature Fish and plant oils Considered the “healthier” fat SATURATED UNSATURATED

34. FATS SATURATED UNSATURATED

35. WHAT IS A “HYDROGENATED” OIL?WHY IS OIL HYDROGENATED? Hydrogenated – means unsaturated fats have been synthetically converted to saturated fats by adding hydrogen WHY? – products are hydrogenated to prevent lipids from separating out in liquid (oil) form – examples include peanut butter & margarine The process of hydrogenation some unsaturated fats with trans double bonds – called Trans Fats – may contribute more to heart disease than even saturated fats

37. WHAT IS THE ROLE OF FAT IN THE BODY? Energy storage – a gram of fat stores more than twice as much energy as a gram of a polysaccharide We store fat in adipose tissue, the adipose tissue also cushions vital organs like the kidneys Forms the subcutaneous layer beneath the skin that insulates the body

38. PHOSPHOLIPIDS Why are phospholipids essential for cells? They make up the cell membranes

39. STRUCTURE OF A PHOSPHOLID Glycerol 2 fatty acid tails Phosphate group Fatty acid tails are hydrophobic Phosphate group has negative charge Phosphate end is hydrophilic “Split Personality”

40. Phospholipids in water Hydrophilic heads “attracted” to H2O Hydrophobic tails “hide” from H2O can self-assemble into “bubbles” bubble = “micelle” can also form a phospholipid bilayer

41. Why is this important? Phospholipids create a barrier in water define outside vs. inside they make cell membranes!

42. STEROIDS What are steroids? Steroids include many hormones and cholesterol

43. STEROID STRUCTURE A carbon skeleton consisting of 4 fused C rings What makes various steroids different? different steroids created by attaching different functional groups to rings different structure creates different function examples: cholesterol, sex hormones

44. Cholesterol Important cell component animal cell membranes precursor of all other steroids including vertebrate sex hormones it is synthesized in the liver of vertebrates high levels in blood may contribute to cardiovascular disease

45. Cholesterol helps keep cell membranes fluid & flexible