Biological Molecules

1. Biological Molecules Part 2

2. Review of Reactions • Condensation/Dehydration/Synthesis • Monomers joined together • One monomer releases H+, the other releases OH- • Hydrolysis Reaction • Polymers broken down • required • H+ joins one , OH- joins other

3. Dehydration reactions

4. Not Dehydration

5. Cells contain four major families of small carbon-based organic molecules covalent bonds between the building block monomers create polymeric macromolecules 3:3

7. Proteins • Large molecules ( ) that form some of the cytoplasm, hormones, globulins, antibodies, and • Provides structure (ex: and cartilage) • Composed of group (NH2) group (COOH) and a common attached to the side chain R • R group can be one H or as complex as a system

8. R groups • amino acids in total • All have different R groups

9. Proteins • Amino acids joined together through reactions (water produced) to form polymer and . • Polypeptide chains can be between 50 – amino acids long are referred to as . • During the dehydration reaction, a bond forms between N of group of one amino acid and the C of the group of the other amino acid • The peptide bond is (slightly positive H and slightly negative O)

10. Formation of Peptide Bond

11. Proteins • Primary structure • Amino acid sequence of a chain (a single linear chain of amino acids) • Secondary structure • Amino acids within the polypeptide chain begins to form H-bonds • H-bonds cause the chain to either form a , a sheet, loops, or turns within the same chain

12. Proteins

13. Tertiary structure • The different structures within the polypeptide chain come together and arrange themselves to form a shape due to different non-covalent interactions (H- bonding, ionic interactions, van der waals forces, and interactions) • Once this globular shape is finalized, covalent bonds form between two (S-S) in different R groups to the proteins shape together

15. Quantenary Structure • More than one chain comes together to form this • many, although not all engage in this type of structure

17. hemoglobin each red blood cell contains ~3x108 hemoglobin molecules

18. Proteins • Tertiary structures can be changed or denatured by heat, , UV light or pH. • Denaturation can be temporary or • What is denaturation?

19. Carbohydrates • Can be classified as monosaccharides, disaccharides, and • have carbon chains between 3-7 C’s in length • Ex) 3C monosaccharides = triose 4C monosaccharides = pentose 6C monosaccharides = • Two monosaccharides joined together through reactions form a • A disaccharide can be broken down through to form two • Polysaccharides are long chains of • Ex) cellulose or starch

21. Carbohydrates

22. Monosaccharides form disaccharides 3:9

23. Basic Photosynthesis Works hand in hand with cellular respiration

24. Glucose monomers linked by glycosidic bonds form storage carbohydrates starch in plants glycogen in animals polysaccharides Polysaccharides also play an important role in cell structure and cell signaling 3:10

26. Polysaccarides Cellulose Glycogen Starch Made up of glucose monomers Glucose is stored in this form in plant cells Can be hydrolysed into glucose monomers if need for cellular respiration branching glycogen • Made up of monomers • Makes up the cell in plant cells • No • Made up of glucose monomers • Glucose is stored in this form in animal cells • Can be into glucose monomers if need for cellular • Extensive branching

27. Lipids

28. Lipids - Triglyceride • contains C, H, and O • no fixed ratio of atoms • ex: fats and oils • found in cell • also used for storage • all have two separate building blocks: 1) 1 glycerol 2) 3 fatty acids * 3 fatty acids and one glycerol make 1 lipid molecule

29. Lipids Oils: • liquids at room temperature • many bonds in fatty acids Fats: • solid at room • fewer bonds Waxes: • at room temperature • longer carbon backbones 15

30. Lipids • H from each OH of glycerol joins with OH from carboxyl group of each fatty acid through a reaction • Results in the formation of (neutral fat) + 3H2O Glycerol

33. Saturated vs. Unsaturated

35. Lipids-Phospholipid Phospholipids • Lipid with a group • Usually a neutral fat with a phosphate on one of the fatty • Found in cell (phospholipid bilayer) • Polar end in high water concentration area cytoplasm or fluid

36. Phospholipids 3:12

37. Hydrophilic Molecules 2:17

38. Hydrophobic molecules Nonpolar molecules and nonpolar portions of molecules tend to aggregate in water = Water cannot form hydrogen bonds with nonpolar substances Water will form hydrogen bonds with other water molecules and surround a nonpolar molecule The less hydrophobic surface, the more energetically favorable it is for water to surround nonpolar molecules How is this accomplished? By nonpolar molecules aggregating C-C and C-H bonds are the most common nonpolar bonds in biological systems 2:18

39. Hydrophobic Effect 2:19 Hydrophobic effect is not an attraction between particles but an avoidance of an energetically unfavorable state

40. Hydrophobic effect 2:20

41. A lipid bilayer prevents the diffusion of polar substances solutes spontaneously diffuse from a region of high concentration to a region of low concentration a lipid bilayer prevents the diffusion of polar substances out of the inner compartment (also prevents the inward diffusion of polar substances) 3:13

42. Types of Lipids steroids: 1. : • a. component of cell membranes that affects stiffness • b. to synthesize other steroids/hormones • e.g. testosterone & estrogen 2. hormones: • growth/functioning of specific cells • chemical messengers between cells • e.g. stimulates sperm production

43. Nucleic Acids Purines Pyriminadines Cytosine Adenine

44. Nucleic Acids • Are formed of subunits called • Nucleotide are composed of a base, a sugar, and a acid • In DNA the nitrogenous base may be one of 4: – adenine, guanine Pyrimidines – ,

45. DNA • DNA (Deoxyribonucleic Acid) is sided with H-bonds between the bases holding it together • Purines have two bonds between them while have three hydrogen bonds

46. RNA • RNA (Ribonucleic acid) is stranded • RNA contains the base instead of thymine

47. ATP • ATP (Adenosine Triphosphate) is a containing an adenine, a ribose sugar, and 3 groups (instead of one) • Between each phosphate group are rich bonds • This is where the cell obtains its ATP ADP + phosphate + energy

48. By the end of this section you should know: • Demonstrate knowledge of dehydration synthesis and hydrolysis as applied to organic monomers and polymers • Differentiate among carbohydrates, lipids, proteins, and nucleic acids with respect to chemical structure • Recognize the following molecules in structural diagrams: ATP, DNA, disaccharide, glucose, glycerol, hemoglobin, monosaccharide, neutral fat, phospholipids, polysaccharide (starch, glycogen, and cellulose), ribose, RNA, saturated and unsaturated fatty acids, steroids • Recoginze the empiracle formula of a monosaccharide as CnH2nOn • List the main functions of carbohydrates • differentiate among monosaccharides (e.g., glucose), disaccharides (e.g., maltose), and polysaccharides • differentiate among starch, cellulose, and glycogen with respect to: function, type of bonding, level of branching • describe the location, structure, and function of the following in the human body: neutral fats, steroids, and phospholipids

49. compare saturated and unsaturated fatty acids in terms of molecular structure • list the major functions of proteins • draw a generalized amino acid and identify the amine, acid (carboxyl), and R-groups • identify the peptide bonds in dipeptides and polypeptides • differentiate among the following levels of protein organization with respect to structure and types of bonding: primary, secondary (alpha helix, beta pleated sheet), tertiary, quaternary (e.g., hemoglobin) • list the major functions of nucleic acids (RNA and DNA) • name the four nitrogenous bases in ribonucleic acid (RNA) and describe the structure of RNA using the following terms: nucleotide (ribose, phosphate, nitrogenous base, adenine, uracil, cytosine, guanine), linear, single stranded, sugar-phosphate backbone • name the four nitrogenous bases in DNA and describe the structure of DNA using the following terms: nucleotide (deoxyribose, phosphate, nitrogenous base, adenine, thymine, cytosine, guanine), complementary base pairing, double helix, hydrogen bonding, sugar-phosphate backbone • compare the general structural composition of DNA and RNA • relate the general structure of the ATP molecule to its role as the “energy currency” of cells