Biomolecules

1. Biomolecules The Chemical Building Blocks of Life

2. The Chemistry of Carbon • Organic molecules contain carbon • Carbon’s four valence electrons allow it to form up to four covalent bonds • Hydrocarbons consist only of C and H • Propane CH8 • It can easily bond to itself and form long chains • Linear - Cyclic - Branched

3. Functional Groups • Chemical properties and reactivity are a result of functional groups • Functional groups maintain chemical properties no matter where they occur • Polar molecules are hydrophilic • Nonpolar molecules are hydrophobic • The degree to which organic molecules interact with water affects their function • Hydroxyl group (-OH) is one of the most common functional groups, it will make a molecule water soluble

4. The Molecular Logic of Life Small molecules, common to all organisms, are arranged into unique macromolecules (Campbell p. 62)

5. Macromolecules – The Sum of the Parts Many complex biological activities require large macromolecules Macromolecules are polymers poly: “many” mer: “units” ex: proteins, nucleic acids, starches

6. Polymers are built by covalently linking together small similar (or in some cases, identical) subunits/building blocks called monomers mono: “one” mer: “unit” ex: amino acids, nucleotides, monosaccharides

7. 4 Classes of Organic Compounds, or “Biomolecules”-necessary for an organism to survive:Proteins are polymers of amino acidsNucleic acids are polymers of nucleotidesStarches are polymers of simple sugars called monosaccharidesLipids aren’t REALLY polymers, since they don’t have repeating chains. BUT they are important biomolecules. The building blocks (monomers) of some types of lipids are glycerol and fatty acids

8. CondensationIt’s not just for the water cycle anymore!This is how we link monomers together to create polymers • Macromolecules are constructed by covalently bonding monomers by condensation reactions where water is removed from the functional groups of the monomers • Dehydration synthesis (water is removed) • A hydroxyl (-OH) from one monomer and a hydrogen (-H) from another are removed • Anabolic reaction- requires energy

9. Hydrolysis • Hydrolysis is the reverse of condensation • Results in the break down of polymers • Hydration reactions add water and break bonds, releasing energy-- catabolic animation

10. Macromolecules- why are they so important? • Each macromolecule performs complex tasks with precision • The basic structure and function of each class of macromolecules is similar in all organisms (from the simplest bacteria to complex humans)– indicates an evolutionary link.

11. Classes of Biomolecules • Carbohydrates • Lipids • Proteins • Nucleic Acids

12. Basic Function

13. CarbohydratesHow Sweet It Is! • General formula (CH2O)n • Simple sugars or large molecules made of sugar monomers • Monosaccharides (monomer) are covalently linked by condensation reaction to form polysaccharides (polymers)

14. Sugars • Monosaccharides • Five carbon: Ribose • Six carbon: glucose and fructose • Disaccharides • Sucrose • Lactose • Polysaccharides • Starch • Glycogen • Chitin • Cellulose

15. Polysaccharides Two Types for Storage 1. Glycogen – animal energy storage product that accumulates in the liver/muscles - Highly branched GlucoseGlycogenglucosebloodstream 2. Starch – plant energy storage - Helical - Easily digested by animals through hydrolysis

16. Two Types for Structure: • Cellulose Polysaccharide found in plant cell walls • For humans cellulose is indigestible and forms dietary fiber • Made up entirely of β glucoses • Structure is constrained into straight microfibrils • Not an energy source for animals 2. Chitin – insect exoskeletons

17. So what’s the difference between condensation and hydration reactions? • animation

18. Lipids Functions: • Long-term energy storage/insulation (fats) • Structural components of cells (phospholipids) • Cellular messengers (hormones)

19. More FAT • Triglycerides are composed of three fatty acids covalently bonded to one glycerol molecule • Fatty acids are composed of CH2 units and are hydrophobic- contain tons of energy in their hydrocarbons! • Fatty acids can be saturated (all single bonds) or unsaturated (one or more double bonds) • A fat (mostly saturated) is solid at room temp., while an oil (mostly unsaturated) is liquid at room temp.

20. video • Glycerol is a molecule with three carbons in a row, each with a hydroxide group • Fatty acid chains are hydrocarbons • that is, they are composed of mostly carbons and hydrogens. • This is a molecule that is VERY hydrophobic. • When glycerol combines with the fatty acid chains it forms a carboxyl group between them • They link by the loss of a water molecule. Carbon can bond to four different substances, but sometimes it will share more than one pair of electrons. animation

21. Phospholipids • Important structural component of cell membranes • Phosphate group (head) is polar and water soluble (hydrophilic) • Two fatty acid tails are hydrophobic • This allows the phospholipids to • form bilayers and membranes

22. Other Lipids • Steroids • Insoluble in water • Built around a four ringed skeleton • Cholesterol • Component for animal cell membranes • Formation of myelin sheath covering nerves • Hormones • Chemical messengers • Waxes • Many fatty acids linked to a long backbone • Waterproofing in plants, ears, beehives overview

23. Proteins • 50% dry weight of body • Mammal cell contains 10,000 proteins • Enzymes (regulate chemical reactions) • Structural elements (cell membrane, muscles, ligaments, hair, fingernails) • Carriers (regulate what goes into/out of cells) • Send and receive messages (hormones) • Movement

24. Building Blocks of ProteinsAmino Acids • Amino acids (monomers) are linked together to form proteins (polymers) • Each unique sequence of amino acids forms a different protein • All living things (even viruses) use the same 20 amino acids • 20 different Amino Acids • Amino end (NH2) • Carboxyl end (COOH) • Hydrogen • R group – variable component

25. Amino Acids • Amino Acids are grouped by whether R- group is polar or non-polar • Positively charged side chain • Negatively charged side chains • Polar but uncharged side chains • Hydrophobic side chains • Special cases

26. Protein Assembly • AA’s are linked together by joining the amino end of one molecule to the carboxyl end of another • Peptide bond forms a chain called a polypeptide http://www.biotopics.co.uk/as/aminocon.html

27. Protein Structure • Primary structure • Specific linear sequence of AA’s in a polypeptide • Determined from code in inherited genetic material • Changes in primary structure can alter proper functioning of the protein

28. Hormone: Insulin • Frederick Sanger (1940s, 50s), discovered the amino acid sequence of Insulin • Causes cells to take up more glucose, and liver and muscle cells to create glycogen • Diabetes is a deficiency of insulin

29. Carrier: Hemoglobin -Protein that carries oxygen to your cells -Iron an important co-factor, iron deficiency =anemia

30. Sickle Cell Disease

31. Spider silk: a structural protein Spider Silk Video

32. Enzyme: Salivary Amylase • Hydrolyzes starch while chewing

33. Enzyme: Rubisco Catalyzes first step of carbon fixation in photosynthesis

34. Movement: Actin and Myosin

35. Secondary structure • the tendency of the polypeptide to coil or pleat due to H-bonding between R- groups • -helix, -pleated sheet, or random coil

36. Tertiary structure • shape of entire chain; folded, twisted, or • globular • shape related to function and properties

37. Quaternary structure • more than one polypeptide chain

38. Nucleic Acids • Polymers composed of monomer units known as nucleotides • Information storage • DNA (deoxyribonucleic acid) • Protein synthesis • RNA (ribonucleic acid) • Energy transfers • ATP (adenosine tri-phosphate) and NAD (nicotinamide adenine dinucleotide)

39. Nucleotides • Structure • Phosphate • Nitrogenous base • Purines (double-rings) • Adenine and Guanine • Pyrimidines (single-rings) • Cytosine, Thymine, and Uracil • Sugar – either ribose or deoxyribose • pentoses in ring form • Deoxyribose lacks one oxygen

40. Functions of Nucleic Acids • DNA – Physical carrier of genetic information • Restricted to nucleus • RNA – key component of protein synthesis • Messenger RNA (mRNA) – blueprint for construction of a protein • Ribosomal RNA (rRNA) – construction site where the protein is made • Transfer RNA (tRNA) – truck delivering the proper AA to the site of construction

41. The End