Molecular Biology

1. Molecular Biology

2. Elements present in your body other than water… • Carbon-30% of all biomass, original source of C is CO2 from photosynthesis • Hydrogen • Nitrogen • Oxygen • Phosphorus • Sulfur • If carbon is present then the compound is considered organic. • Carbon is the most versatile element b/c of its ability to bond to itself and other elements. It is tetravalent (4 bonds). • If C and H are present it is a hydrocarbon: most are energy sources (fossil fuels)

3. Molecules in living organisms: proteins, carbohydrates, lipids, nucleic acids • Most are polymers of smaller, covalently bonded, molecules called monomers. • Functional groups: groups of atoms with specific chemical properties and consistent behavior. • The consistent behavior of functional groups allows one to recognize the properties of molecules that contain them. i.e. polarity, electronegativity

4. Figure 3.1 Some Functional Groups Important to Living Systems (Part 2) Amines- contain N, act as a base Phosphates- involved in E transfers Sulfur in sulfhydrls make disulfide bridges in protein

5. Figure 3.1 Some Functional Groups Important to Living Systems (Part 1) Hydroxyls- act as an alcohol or polar Aldehydes, Ketones, have one double bond to O Carboxyls have two Os, one double, one single bond

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7. Isomers • Structural isomer- same chemical formula, different arrangement of atoms. Structural Isomers

8. Figure 3.2 Optical Isomers Optical Isomers • Same chemical formula, arranged differently around an asymmetrical carbon Bio

9. Biochemical Unity • Biochemical unity-organisms can acquire needed biochemicals by consuming other organisms. • Because all macromolecules have the same chemistry: • The four biological molecules are present in the same proportions in all living things. • Argument for common ancestor

10. Figure 3.3 Substances Found in Living Tissues 70% water

11. The function of macromolecules is directly related to their 3-D shape and their chemical properties/formula. • This will determine molecular interactions such as solubility.

12. Synthesis Question • Question: Carbon is an extremely important element to all life forms on the planet. Life on Earth, as we know it, could not exist without this element. In no more than three sentences, • A) Identify the ultimate source of all Carbon for living organisms alive today and • B)provide two brief explanations of why Carbon is important molecularly speaking.

13. Scoring Rubric: 1pt. The ultimate source is CO2 from the atmosphere. • 1pt. Discussion of source of carbon for making Carbohydrates, Lipids, Proteins, and Nucleic Acids. • 1pt. Discussion of the tetravalence allowing for a wide range of different molecules. • 1pt. Correct use of scientific terms. • 1pt. Answer has no more than three sentences. (Following Directions.)

14. Molecular Biology • Polymers are formed in condensation reactions AKA dehydration synthesis. • Condensation reactions result in monomers joined by covalent bonds. • These require E http://nhscience.lonestar.edu/biol/dehydrat/dehydrat.html The reverse of a dehydration synthesis is hydrolysis reaction which break apart polymers and turn them into monomers. These make E

15. Figure 3.4 Condensation and Hydrolysis of Polymers (A)

16. Figure 3.4 Condensation and Hydrolysis of Polymers (B)

17. Short polymer Unlinked monomer Dehydration removes a water molecule, forming a new bond Longer polymer Dehydration reaction in the synthesis of a polymer Dehydration and HydrolysisReactions Hydrolysis adds a water molecule, breaking a bond Hydrolysis of a polymer

18. CarbohydratesSee the Carbonyls and Hydroxides?

19. Carbohydrates (C,H,O 1:2:1) • Molecules that contain carbons flanked by a H group and an OH group. • Four major types of carbs: mono, di, poly, and oligosaccharides. • Two major functions: • Source of energy that can be released in a usable form to body tissues • Serve as carbon skeletons for other 3 macromolecules.

20. Monosaccharides • Produced through photosynthesis. • All living cells contain glucose. • Most monosaccharides are in the D series of optical isomers (proteins are L)

21. Figure 3.13 Glucose: From One Form to the Other (Part 2)

22. Figure 3.14 Monosaccharides Are Simple Sugars (Part 1)

23. Figure 3.14 Monosaccharides Are Simple Sugars (Part 2) Structural These are structural isomers.

24. Glycosidic Linkages • Monosaccharides covalently bind together in condensation reactions to form glycosidic linkages. • Glycosidic linkages can be α or β. • Examples of disaccharides sucrose — table sugar = glucose + fructose lactose — milk sugar = glucose + galactose maltose — malt sugar = glucose + glucose

25. Figure 3.15 Disaccharides Are Formed by Glycosidic Linkages (Part 1)

26. Figure 3.15 Disaccharides Are Formed by Glycosidic Linkages (Part 2) ThiThis is cellobiose, a subunit of cellulose, humans don’t have the enzymes to break this down, but cows do. To us it is merely roughage. Cellulose is a very stable glucose polymer, and is the principle component of cell walls.

27. Oligosaccharides (3-20) • Often covalently bonded to proteins and lipids on cell surfaces and act as recognition signals. • ABO blood groups

28. Polysaccharides • Formed by glycosidic linkages, animal and plant energy storage form. • Three forms: starch, glycogen, cellulose, and chitin. • Starch and glycogen easily hydrolyzed for energy. • Starch- all contain alpha linkages, stored in plants. • Cellulose- plant cell wall structure; most abundant organic molecule on earth • Glycogen-energy storage in animals • Chitin- found in exoskeletons and fungi cell walls

29. Polysaccharides • Glucose must be stored as glycogen because glycogen does not exert as much osmotic pressure on the cell as one glucose molecule

30. Figure 3.16 Representative Polysaccharides (A)

31. Carbohydrate Energy Storage

32. Figure 3.16 Representative Polysaccharides (B) Cellulose, Starch, & Glycogen

33. Chemically Modified CHOs • Some CHO can be modified by adding functional groups such as a phosphate or amino group. • Phosphate sugars and amino sugars

34. Lipids –C,H,O • Lipids are hydrocarbons that are insoluble in water because of their nonpolar, covalent bonds. • All the extra H= 2x E of CHO • Hydrophobic. • One lipid molecule consists of a glycerol (alcohol) bonded to 3 fatty acid chains. • The fatty acids are held together through van der Waals forces not covalent bonds; therefore they are not true polymers.

35. Lipids • The bond that holds each fatty acid molecule to the glycerol is formed through dehydration synthesis, and is called an ester linkage. • The ester linkage is a covalent bond.

36. Fatty acid (palmitic acid) Ester Linkage and Lipids Glycerol Dehydration reaction in the synthesis of a fat

37. Math Quiz • Tell if each pH or pOH is an acid, base, or neutral by writing ACID, BASE, or NEUTRAL on the line next to the prompt. (1 points each) • pH 3 ____________ pOH 7 ______________ pH 14 _______________ pH 7 ____________ • pH 4 ______________ pOH 0 ______________ • pOH 14 ____________ pOH 9 _____________ • pOH 2 ____________ pH 10 _____________

38. Calculate pH differences in H concentration pH 2- pH 5 pH 1- pH 2 pH 3- pH 8 pH 7 – pH 10 pH 1- pH 14 pH 1- pH 3 pH 10- pH 14 pH 3- pH 7 pH 5 – pH 10 pH 1- pH 11

39. Figure 3.18 Synthesis of a Triglyceride

40. Lipid Functions • Fats and oils store energy • Phospholipids in cell membrane for structure • Carotenoids • Hormones and vitamins • Fat = insulation (Camels) • Lipids coat neurons for electrical insulation • Oil and wax on skin surface repel water

41. Lipids • One lipid unit is called a triglyceride/triglycerol. • Triglycerides solid at room temp. are fats. • Saturated fatty acid- all C-H bonds are single • Animal fat, least healthy. • Triglycerides liquid at room temp. are oils. • Unsaturated fatty acid (mono, poly) some of the C-H bonds are double causing kinking in the hydrocarbon chain. • Plant oils, lower melt. pt., healthier • Polyunsaturated Fats- many double bonds, usually in plants • Hydrogenated or Trans Fat- Unsaturated turned saturated

42. Saturated vs. Unsaturated

43. Figure 3.19 Saturated and Unsaturated Fatty Acids

44. Phospholipids • A phosphate molecule bonds to the glycerol replacing one hydrocarbon chain (fatty acid). • Since phosphate functional group is (-) it is hydrophilic and attracts polar H20 molecules. • In aqueous environment, phospholipids line up with hydrophobic region “tails” on one end, and hydrophilic “heads” on the other. • Phospholipids form a bilayer.

45. Figure 3.20 Phospholipids (A)

46. Figure 3.20 Phospholipids (B) Phospholipid bilayers form biological membranes.

47. Waxes

48. Steroid Structure

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50. Cell Membranes