Macromolecules

1. Macromolecules 1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic Acids

2. 1. Carbohydrates = organic compounds made up of carbon, hydrogen, and oxygen in the approximate ratio 1:2:1 • Three main categories: a) monosaccharides (simple sugars) b) Diasaccharides (double sugars) c) Polysaccharides (many sugars)

3. A) Monosaccharides AKA simple sugars • These are the building blocks of all other carbohydrates • General chemical formula = CnH2nOn • Monosaccharides are classified based on the number of Carbon atoms present.

4. Some Monosaccharides . . .

5. Most Important Monosaccharides • Glucose (AKA - dextrose) = found in . . . corn syrup, sap of plants, human bloodstream = important energy source (made by plants in photosynthesis, used by plants and animals in cellular respiration) • Galactose = found in the disaccharide lactose

6. Galactosemia - Genetic Enzyme Deficiency: One baby out of every 18,000 is born with a genetic defect of not being able to utilize galactose. Since galactose is in milk as part of lactose, it will build up in the blood and urine. Undiagnosed it may lead to mental retardation, failure to grow, formation of cataracts, and in sever cases death by liver damage. The disorder is caused by a deficiency in one or more enzymes required to metabolize galactose

7. B) Dissacharides AKA double sugars = two simple sugars (monosaccharides) linked together by a dehydration synthesis reaction

8. Most Important Disaccharides • Lactose (milk sugar) = galactose and glucose • Sucrose (table sugar) = glucose and fructose • Maltose (beer sugar) = glucose and glucose Primary function of disaccharides is as a nutritional source of monosaccharides (many of the sugars found in foodstuffs are disaccharides).

9. C) Polysaccharides AKA complex sugars = large numbers of simple sugars linked via dehydration synthesis = used by living things for energy storage and as structural elements = most abundant types of carbohydrates

10. Types of Polysaccharides • Two physiologically important polysaccharides are: 1. Starch (made exclusively by plants) and 2. Glycogen (made by animals) These two molecules are very similar: • They are both polymers of glucose • They are joined by the same types of bonds (1-4 alpha-glycosidic bonds) • Glycogen tends to be a bit more branched than starch but not quite as long

11. A Little More about STARCH • There are two basic kinds of starch: amylose and amylopectin. • Amylose is found in algae and other lower forms of plants. It is a linear polymer of approximately 600 glucose residues. • Amylopectin is the dominant form of starch in the higher plants. It is a branched polymer of about 6000 glucose residues with branches on 1 in every 24 glucose rings.

12. Two Types of Starch • Branched • No branching

13. A little more about Glycogen • Glycogen has almost the same structure as amylopectin, with two minor differences: - glycogen is roughly twice as large - glycogen has roughly twice as many branches • Advantage of branched polysaccharides . . . - enzymes start at one end of the polymer and cut off glucose molecules one at a time - more branches = more points at which the enzyme can break apart the polymer. Thus, a highly branched polysaccharide is better suited for the rapid release of glucose than a linear polymer.

14. Structural Polysaccharides • Cellulose - used to form the walls of plant and bacterial cells. - is the most abundant biological molecule - is a linear polymer of glucose residues that resembles amylose BUT the glucose units are linked differently.

15. Structural Differences between Starch and Cellulose

16. Other Carbohydrates • Derivative carbohydrates = differ from other carbohydrates because they contain atoms other than C, H, O e.g. sugar phosphates – important in cellular respiration and photosynthesis amino sugars – major component of cartilage chitin – principle structural polysaccharide in the exoskeleton of insects/crabs/lobsters and in the cell walls of Fungi

17. 2. Lipids = organic compounds that contain carbon, hydrogen, and oxygen (different ratio than carbohydrates – a lot less O) = large / diverse group that are related by their solubility in nonpolar organic solvents and general insolubility in water. = include: A) triglycerides, B) waxes, C) phospholipids, D) steroids

18. A) Triglycerides AKA Fats and Oils • Function = Energy storage (9cal/g) Insulation Cushioning • Structure = made up of a glycerol molecule with three fatty acids attached via dehydration synthesis

19. Types of Triglycerides Saturated Triglycerides Unsaturated Triglycerides One or more double bonds exist between carbon atoms . . . MORE H atoms could be added to the molecule (mono =1 double bond) (poly = many double bonds) Formed by plants (fish too!) Liquid at room temperature “OILS” • No double bonds exist between Carbon atoms . . . MAXIMUM number of H atoms possible are present in the molecule • Formed by animals • Solid at room temperature (higher melting point) • “FATS”

20. Triglycerides and Human Health • Unsaturated vegetable oils are often hydrogenated (in order to create spreadability, increase shelf life, improve texture, etc.) • This has had unintended consequences . . . Some of the double bonds are isomerized (converted from cis fatty acids into trans fatty acids) Trans-fats are associated with: increased heart disease; cancer; diabetes; obesity; autoimmune diseases; reproductive problems.

21. Trans and Cis Fatty Acids

22. B) Waxes • Function – Water proofing, protection versus microorganisms, structural elements. • Sources - The leaves and fruits of many plants have waxy coatings, which may protect them from dehydration and small predators. The feathers of birds and the fur of some animals have similar coatings which serve as a water repellent. • Examples: Beeswax, Carnauba Wax, Lanolin (Wool wax)

23. C) Phospholipids • Structure: similar to triglycerides • Made up of a glycerol molecule, 2 fatty acids, and one phosphorous containing molecule

24. PhospholipidFunction = Phospholipids form the membranes that surround the cell and intracellular organelles such as the mitochondria. These membranes = fluid, semi-permeable bilayers that separate the cell's contents from the environment • fluidity allows cell to change shape • semi-permeability allows free diffusion of some small molecules (O2, CO2, small hydrocarbons)but not charged ions, polar molecules or other larger molecules (glucose).

25. D) SteroidsStructure – 4 fused carbon rings Example Specific function Moderates fluidity of membranes Cholesterol = Fluidity Promotes male sex development and maintain male sex characteristics Suppresses inflammation reactions and regulates mineral and sugar metabolism Regulates events during pregnancy • Cholesterol • Testosterone • Cortisone • Progesterone

26. Proteins Collagen Myoglobin = organic compounds made up of carbon, hydrogen, oxygen, nitrogen, sulfur, and sometimes phosphorous. = polymers of amino acids connected via dehydration synthesis reactions Primary Functions: 1. Makeup cellular structures 2. Molecular Transport (within body, within cell) 3. Chemical messenger 4. Makeup connective tissues 5. Chemical reactions (speed up)

27. Protein Structure • Typical amino acid structure • Amino group of one A.A. reacts with the carboxyl group of another A.A.to create a peptide bond (another dehydration synthesis reaction) • A few amino acids linked = peptides • Many amino acids linked = polypeptides • Folded / linked polypeptides = proteins

28. Levels of Protein Structure Structural features of proteins are usually described at four levels of complexity Primary Structure: • linear arrangement of amino acids in a polypeptide

29. Secondary Structure • Reactions between R groups of amino acids within the same polypeptide chain create coils or pleated sheets Fibroin – pleated sheets often found in structural proteins such as spider web “silk”

30. Tertiary Structure • refers to the three dimensional globular structure formed by folding of the polypeptide chain

31. Quaternary structure: • Refers to the large complex created when multiple polypeptides combine into a single, larger protein. • E.g. Hemoglobin has quaternary structure due to association of two alpha globin and two beta globinpolyproteins.

32. 4. Nucleic Acids DNA RNA Ribonucleic Acid Polymer of nucleotides 4 different nitrogenous bases: adenine; guanine; cytosine; and uracil. Sugar = Ribose Single stranded 3 types – rRNA, mRNA, tRNA • Deoxyribonucleic Acid • Polymer of nucleotides • 4 different nitrogenous bases: adenine; guanine; cytosine; and thymine. • Sugar = Deoxyribose • Double Stranded (double helix) • 3 types – nuclear and mitochondrial (and in chloroplast too!)

34. DNA STRUCTURE

35. The way this works . . . . . . • A & T always pair (2 H bonds, “purines”) • C & G always pair (3 H bonds - “pyrimidines”) • Uracil replaces Thymine in RNA • Opposite DNA strands are “antiparallel” (because they run in opposite directions) and complementary. • RNA copies that are made from a strand of DNA are complementary as well (with U replacing T)

36. Try This! • What is the complementary DNA strand for the following? G G T A A C G GG T A T A A T G G A • What would an mRNA copy of the above DNA strand look like?

37. Protein Synthesis

38. Protein Synthesis • DNA unzips • mRNA copy is made of gene (all the nucleotides that code for one polypeptide) • mRNA leaves the nucleus and finds a ribosome (in ER or Cytoplasm) • tRNA (with Amino Acids attached) matches up with the mRNA with ribosome’s help • A.A. Get linked together, tRNA moves off to grab more A.A.

39. Amino Acids and mRNA Code

40. Try This! • DNA STRAND TO BE COPIED: TAC GGA GTA ACA ACT • What would the mRNA look like? AUG CCU CAU UGU UGA • Which amino acids make up this small peptide? MET – PRO – HIS – CYS - STOP (START) • Wobble Hypothesis – many amino acids are coded for by a number of codons – varying only by the last letter – this reduces the impact of mistakes in translation