Molecules of Life- Chapter 3 (aka- Biochemistry)

1. Molecules of Life- Chapter 3(aka- Biochemistry)

2. Upon finishing this chapter you should be able to: • Describe the characteristics of carbon that make it the backbone of organic molecules. • Be familiar with the different ways of representing organic compounds. • Understand how functional groups work to create different organic building blocks for living things. • Understand that cells use enzymes to mediate different chemical reactions between organic molecules. • Describe and discuss carbohydrates, lipids, proteins and nucleotides and their importance to living systems.

3. Organic Compounds are: • Molecules containing carbon and at least one hydrogen • Probably older than life on this planet • The molecules of life

4. Why carbon? Important due to versatile bonding behavior Can share electrons Form +4 ion Form -4 ion Covalent bonds 4

5. Definitions: • Hydrocarbons- organic molecule made of only carbon and hydrogen (methane, gasoline)

6. Examples of Organic Compounds • Carbohydrates • Lipids • Proteins • Nucleotides The molecules of life!

7. Bonding Arrangements Carbon atoms can form chains or rings Other atoms project from the carbon backbone Functional group- atom or compound that bonds with a carbon in an organic molecule Glucose (ball-and-stick model) 7

8. Glucose 8 • Structural formula • Space filling model • It can be in any of these forms • Straight chain • Ring

9. Four Families of Building Blocks 9 Four main families of small compounds: • Simple sugars- make up carbohydrates • Fatty acids- make up lipids • Amino acids- make up proteins • Nucleotides- make up nucleic acids • They can contain from two to 36 carbon atoms

10. The functional groups attached to the carbon backbone of an organic compound help determine the role that compound plays in a biological system.

11. Examples of Functional Groups Methyl group - CH3 Hydroxyl group - OH (in alcohols & sugars) Amino group - NH3+ Carboxyl group - COOH (in amino acids and fatty acids) Phosphate group- PO3- (in DNA) Sulfhydryl group- SH 11

12. Estrogen and testosterone are hormones responsible for observable differences in traits between male and female wood ducks Differences in position of functional groups attached to ring structure Functional Groups in Hormones An Estrogen Testosterone 12

13. Carbohydrates

14. Carbohydrates are the most plentiful organic compounds Monosaccharide- one sugar monomer Disaccharide- two sugar monomers Polysaccharide- many sugar monomers

15. Most carbohydrates consist of carbon, hydrogen, and oxygen in a 1:2:1 ratio or(CH2O)n. • Cell use them as structural materials and transferable or storable forms of energy.

16. The Simple Sugars- monosaccharides and disaccharides 1. Monosaccharide One monomer of sugar Sweet tasting Readily dissolves in water 5-6 carbon atoms in ring 2 or more –OH groups Examples: glucose, ribose, deoxyribose 16

17. Monosaccharides Simplest carbohydrates Most are sweet tasting, water soluble Most have 5- or 6-carbon backbone Glucose (6 C) Fructose (6 C) Ribose (5 C) Deoxyribose (5 C) Structure of glucose 17

18. Disaccharides Type of oligosaccharide Two monosaccharides covalently bonded Formed by condensation reaction 2 or more sugars Lactose (glucose + galactose) - Milk sucrose (fructose + glucose) –Table sugar glucose fructose + H2O sucrose Figure 3.8bPage 40 18

19. Complex Carbohydrates 3. Polysaccharides (complex carbohydrates) Straight or branched of many monomers Examples: cellulose (plants structure) starch (plant storage) glycogen (animal storage) chitin – (exoskeletons animals & fungi) 19

20. Cellulose & Starch Differences in bonding patterns between monomers yield different properties amylose (a starch) cellulose 20

21. Chitin Chitin occurs in protective body coverings of many animals, including ticks. Chitin has the addition of a functional group containing nitrogen that makes it so different from cellulose or starch. 21

22. Summary of Carbohydrates 22 Carbohydrates include simple sugars – monosaccharide (ex. glucose), disaccharide – oligosaccharide (ex. sucrose) and polysaccharides (ex. starch). Cells use some carbohydrates as structural materials, others as energy units, and others as transportable or storage forms or energy.

23. Cont. 23 Carbohydrates are the most abundant biological molecules in nature. The simple sugars function as quick energy sources or transportable forms of energy. Complex carbohydrates are structural materials or energy reservoirs.

24. Lipids 24

25. Lipids Most include fatty acids Fats Phospholipids Waxes Sterols and their derivatives have no fatty acids Tend to be insoluble in water Mix with nonpolar substances Fats & Fatty Acids 25

26. Properties or functions 26 Complex lipids function as: *the body’s energy reservoirs *structural components of cell membranes *waterproofing or lubricating substances *Signaling molecules

27. Cont. 27 • Lipids are greasy or oily to the touch. • Lipids are characterized by being water-insoluble and soluble in nonpolar organic solvents. • Although the word lipid is commonly used as a synonym to fat, the latter is a subgroup of triglyceride lipids.

28. New terms 28 Saturated Fatty Acids – single bonds, solid at room temperature Unsaturated Fatty Acids – one or two double bonds, liquid at room temperature Adipose tissue – stored triglycerides, used as insulation Waxes- repel water, found in plant cuticle

29. Good vs Bad 29 Unsaturated fatty acids are of similar form, except that one or more functional groups exist along the chain. Bad lipid. Saturated fatty acids do not contain any double bonds or other functional groups along the chain. Single covalent bonds and hydrogen only! The term "saturated" refers to hydrogen. The fatty tissues of animals contain large amounts of long-chain saturated fatty acids.

30. Fatty Acids Carboxyl group at one end Carbon backbone Saturated or unsaturated linolenic acid oleic acid stearic acid 30

31. Saturated Fats • Carbon atoms are “saturated” with hydrogen atoms. No double bonds in the fatty acid chain. Dietary cause of “bad” cholesterol. Low density lipoproteins (LDL) levels increase with saturated fat consumption. No more than 10% of calories should be consumed in saturated fats

32. Saturated Fats are found in: Animal products such as: cheese, fatty meat, ice cream, butter, whole milk, Also found in oils such as palm, cottonseed, coconut and palm kernel oils

33. Trans Fats • Formed when unsaturated fats are chemically changed to saturated fats and “hydrogenated.” • Trans fats tend to extend shelf-life of products since they stay solid at room temperature. They also spoil much less quickly than other fats. • Raises levels of LDL (“bad” cholesterol) and lowers levels of HDL (“good” cholesterol) • Has been linked to heart disease and stroke. • Found in fried foods, commercial baked goods, margarine and processed foods

34. Comparison of frequently used cooking products: • Foods containing artificial trans fats formed by partially hydrogenating plant fats may contain up to 45% trans fat compared to their total fat. • Baking shortenings generally contain 30% trans fats compared to their total fats, • Animal fats from ruminants such as butter contain up to 4%. • Margarines not reformulated to reduce trans fats may contain up to 15% trans fat by weight.

35. linolenic acid oleic acid Unsaturated Fats • Have at least one double bond. Creates a “kink” in the molecular structure. • Helps lower LDL levels. • Highly caloric. • Two types: monounsaturated and polyunsaturated.

36. Monounsaturated Fatty Acids • One double bond in the fatty acid. • Recent studies have shown MUFAs to protect against heart disease and improve overall health and reduce belly fat (a risk factor for heart disease) • Found in: • Olive oil, • peanut oil, • canola oil, • avocados, • nuts • seeds

37. Polyunsaturated Fats • More than one double bond in chemical structure • Omega-3 fatty acids protect against heart disease, lower blood pressure and protect against irregular heart beats. • Found in: • Fatty, cold-water fish (such as salmon, mackerel and herring) • flaxseeds, • flax oil • walnuts

38. Sterols and Derivatives No fatty acids Rigid backbone of four fused-together carbon rings Cell membrane component Cholesterol - most common type in animals Cholesterol 38

39. Proteins

40. Facts 40 Proteins such as enzymes, structural materials, signaling molecules, and transporters. Of all biological molecules, proteins are the most diverse. Some kinds speed up reactions, others are the stuff of spider webs or feathers, bones, hair, and other parts of the body.

41. Cont. 41 Nutritious types abound in seeds and eggs. Many proteins move substances, help cells communicate or defend against pathogens. Cells assemble thousands of different proteins from 20 kinds of amino acids.

42. New Term 42 • Amino acids – small compound with amino group, carboxyl group, hydrogen and one or more R groups. • Make up proteins • Synthesis of proteins is controlled by DNA

43. Amino Acid Structure Carboxyl group Amino group R group tryptophan (trp) 43

44. Protein forms 44 Primary – straight chains Secondary – twisted chains Tertiary – compact coils Quaternary – several chains folded into rounded shapes

45. Summary of Proteins 45 Structurally and functionally, proteins are the most diverse molecules of life. A protein’s primary structure is a sequence of covalently bonded amino acids that make up a polypeptide chain. Local regions of a polypeptide chain become twisted and folded into helical coils, sheet like arrays, and loops. These arrangements are the protein’s tertiary structure.

46. Importance of Protein Structure

47. Just One Wrong Amino Acid….. 47 • Hemoglobin • Made of tightly packed globins • Contain a heme group • Iron at center • Two forms • Alpha • Beta • If last amino acid is changed it can become nonpolar vs the normal polar (HbS)

48. Sickle Cell Anemia Caused by two mutated copies (HbS) of Hb gene Low oxygen causes red blood cells to clump Clumping prevents normal blood flow Over time, may damage tissues and organs throughout the body Sickle shape to RBC’s Affects African-American populations 48

49. Sickle-shaped red blood cells normal blood cells 49

50. Clumping of cells in bloodstream Circulatoryproblems, damage to brain, lungs, heart, skeletal muscles, gut, and kidneys Effects of sickle cell anemia Heart failure, paralysis, pneumonia, rheumatism, gut pain, kidney failure Spleenconcentrates sickle cells Spleen enlargement Immune system compromised Rapid destruction of sickle cells Anemia, causing weakness,fatigue, impaired development,heart chamber dilation 50 Impaired brain function, heart failure