Chemistry in Focus 3rd edition Tro

1. Chapter 16 Biochemistry and Biotechnology Chemistry in Focus 3rd editionTro

2. Brown Hair, Blue Eyes, and Big Mice • Study of the molecular blueprints that are genes has increased our understanding of how we think, how we behave, and what diseases we might develop. • We understand not only how a molecular sequence works, but how to take it from one organism and implant it in another. • 4 type of molecules in living organisms • Lipids • Carbohydrates • Proteins • Nucleic acids

3. Lipids and Fats • Lipids are cellular components that are insoluble in water, but extractable in nonpolar solvents. • Fats, oils, fatty acids, steroids, some vitamins • They form the structural components of biological membranes and reservoirs for long-term energy storage. • They contain twice as much energy per gram than any other class of biochemical compounds. • Efficient energy storage

4. Fatty Acids • One type of lipid • Organic acid with a long hydrocarbon tail • General formula RCOOH:

6. Triglycerides • Fats and oils are a combination of glycerol and three fatty acids.

7. Tristearin • Structure/property relationships • Long hydrocarbon chains: nonpolar, immiscible with water • Energy is extracted via oxidation of these long chains (as in gasoline). • Chains are saturated: efficient packing, solids • Fat is conveniently stored in the body. • Provides thermal insulation

8. Triolein • Main component of olive oil • Double bonds in R groups interferes with efficient packing, liquid at room temperature

9. Trilinolenin • Polyunsaturated fat: multiple double bonds in the hydrocarbon chains • Animal fats tend to be saturated. • Plant fats tend to be unsaturated. • Variations in structure serve different purposes in the human body.

13. Carbohydrates • Chemical formulas are multiples of CH2O, carbon and water • Function in the body as short-term energy storage • Chemical structure related to: • Carbohydrates are polyhydroxy aldehydes, or ketones, or their derivatives.

14. Glucose • This is a dynamic system, but at any instant more molecules are in the ring form.

15. Glucose Properties • Hydroxyl groups mean strong hydrogen bonding with each other and with water. • Solubility in body fluids leads to function as a quick energy source. • Since it is partially oxidized, it yields less energy per gram than octane or lipids. • Balance between efficient energy storage and ease of access to that energy

16. Fructose • Isomer of glucose • Two CH2OH groups mean it is more soluble in water and sweeter. • Takes less to offer same sweetness

17. Saccharides • Monosaccharides – carbohydrates composed of a single ring • Disaccharides – joined monosaccharides, double ring structures

18. Complex Carbohydrates • Polysaccharides • Most common are starch and cellulose • Subtle molecular difference (the oxygen linkage between rings and subsequent nature of resulting hydrogen bonds) means a dramatic macroscopic result. • Human enzymes cannot cut chains of cellulose.

22. The body CAN metabolize proteins. The body metabolizes proteins ONLY as a last resort. Proteins have much more important other work to do in the body. Proteins

23. Protein Functions • Compose much of the physical structure of the body (muscle, hair, skin) • Act as enzymes to control chemical reactions • Act as hormones to regulate metabolic processes • Transport oxygen from lungs to cells • Act as antibodies

24. Protein molecules are long chains of repeating units of amino acids. • Differences among amino acids arise from different R groups. • Changing the number and order of these amino acids changes the functionality of the protein. • The simplest R group is the hydrogen atom, and the amino acid is glycine.

30. The Peptide Bond • The acidic end of one amino acid reacts with the amine side of another to form a peptide bond. • Two linked amino acids is called a dipeptide. • Chains with 50 units or less are polypeptides; chains with over 50 units are called proteins.

31. Sickle Cell Anemia • Hemoglobin (Hb) is a medium size protein with a molecular formula that contains close to 10,000 atoms: C2952H4664O832S8Fe4 • Replacing polar glutamate with nonpolar valine at one position, on two of these chains, lowers the solubility of Hb resulting in red blood cell deformation.

33. Protein Structure • The structure of a protein is finely tuned to achieve a specific function. • We characterize protein structure in four categories: • Primary • Secondary • Tertiary • Quaternary

34. Primary Structure • The amino acid sequence held together by peptide bonds • Abbreviations like gly-val-ala-asp are used to note the sequence of the amino acid.

35. The way the amino acid chain orients itself along it axis Alpha-helix Pleated sheet Secondary Structure

36. Alpha-Helix • Helical shape is maintained by hydrogen bonds between different amino acids along the protein chain. • α-keratin is an alpha-helix and is responsible for the elasticity of hair and wool. • It works like a spring.

37. Protein forms zig-zag chains that stack neatly Silk is pleated sheet Inelasticity due to full extension of protein chains Softness due to sliding of sheets past each other Pleated Sheet

38. Tertiary and Quaternary Structure • Tertiary structure is the bending and folding due to interactions between amino acids on the chain. • Completely extended • Globular or ball-like • Overall shape of the particular protein strand • Arrangement of subunits of the protein chain in space is quaternary structure.

39. Interactions of R Groups to DetermineTertiary and Quaternary Structure

40. Common Proteins: Hemoglobin • Entire structure not known until late 1950s • HB folds to hold four flat molecules called heme groups. • Pick up oxygen at lungs • Release it at cells undergoing glucose oxidation • Interior of Hb molecule is highly nonpolar. • Repels water • Allows oxygen in and out • Exterior is polar • Hemoglobin is soluble in water.

42. α-Keratin • Composes hair and wool • α-helix structure maintained by hydrogen bonding • Hair • 3 α-helices in a coil held by hydrogen bonds (easy to change) and disulfide linkages (require chemical treatment)

43. Acts as an enzyme Cleaves polysaccharide units within cell walls Walls explode killing the bacteria In nasal mucus and tears Discovered by Alexander Fleming in 1922 Lysozyme

44. Acts as a hormone Synthesized in the pancreas Small (51 amino acids) Promotes entry of glucose into muscle and fat cells, lowering blood glucose level Diabetics must inject insulin. Insulin

45. Nucleic Acids • The templates from which all proteins are made • Two types • DNA (deoxyribonucleic acid) • Occurs in cell information center • RNA (ribonucleic acid) • Occurs throughout interior of cells

46. Nucleotides

47. Nucleotides • Phosphate and sugar groups are identical in every nucleotide. • Four different bases • A, adenine • T, thymine • C, cytosine • G, guanine • Codon • A group of three bases that codes for one amino acid • With minor exceptions, the code is universal; it is identical in all organisms, from bacteria to humans.

48. DNA • Occurs in chromosomes, found in the nucleus of most cells of the human body • There are 46 in humans • Each set of DNA contains all the DNA required to specify an entire person. • Organs make those proteins specific for their own functioning. • But the blueprint is there for everything else too

50. DNA Replication • Mechanism elucidated by Watson, Crick, and Franklin in 1953 • Complementary base units are formed (with the help of enzymes) after the double-helix unzips. • Two daughter DNA strands formed • Daughter DNA molecules are identical in every way to the parent.