THE CHEMISTRY OF LIFE

1. THE CHEMISTRY OF LIFE

2. THE CHEMISTRY OF LIFE Biochemistry is the study of organic chemistry, mainly the compounds known as carbohydrates, lipids, proteins, and nucleic acids. All living things are made up of various chemical compounds.

3. The Nature of Matter Atoms are the basic building blocks of matter Elements are substances which are made of only one kind of atom Compounds are a combination of two or more kinds of atoms in a defined proportion

4. Structure of Atoms

5. Structure of Atoms Nucleus – made up of protons (+ charge, 1 atomic mass unit) and neutrons (no charge, 1 atomic mass unit) # of protons = # of neutrons Electrons – orbit the nucleus (- charge, very little mass) determine the chemistry of atoms first energy level contains up to 2 electrons outside levels can hold up to 8 electrons when an electron orbital is full the atom is chemically inactive if orbital in not full the atom “looks” to gain, lose, or share electrons with other atoms

6. Structure of Atoms http://www.classzone.com/cz/books/bio_09/resources/htmls/animated_biology/unit1/bio_ch02_0059_ab_atombond.html (Great Review of atoms and bonding!)

7. Mass number & Atomic Number Atomic number is equal to the number of protons Mass number (atomic mass) is equal to the number of protons plus the number of neutrons

9. Isotopes Atom of an elements that has a different number of neutrons from that of other atoms of the same element Radioactive isotopes are unstable and break down at a constant rate over time (some can be used as tracers)

10. Isotopes of Carbon

11. Chemical Bonding Ionic bonds – Fig. 2-3 – form when atoms gain or lose electrons, become chemically charged and are attracted to each other http://www.dnatube.com/video/366/Ionic-Bond

12. Chemical Bonding Covalent bonds – Fig. 2-4 – formed when atoms share one or more pairs of electrons http://www.dnatube.com/video/1290/Covalent-bond

13. Chemical Bonding Van der Waals forces – Fig. 2-5 – a slight attraction that develops between the oppositely charged regions of nearby molecules

14. Properties of Water H2O – most important inorganic compound; All organisms need H2O to survive. Formed by polar covalent bonds between hydrogen & oxygen inorganic – contains no carbon/hydrogen bonds organic – contains carbon

15. Properties of Water Polar Covalent Bonds are formed when partial positive (+) and partial negative (-) charges are formed as a result of unequal sharing of electrons

16. Properties of Water Polar Covalent Bonds are formed when partial positive (+) and partial negative (-) charges are formed as a result of unequal sharing of electrons

17. Properties of Water – Hydrogen Bonds Hydrogen bonds are weak electrical attractions between the partial negative charge of one molecule and the partial positive charge of a different molecule http://www.youtube.com/watch?v=lkl5cbfqFRM

18. Properties of Water Cohesion is the attraction of molecules of the same substance (Fig. 2-8). Because of cohesion of H2O molecules, H2O is able to store a lot of heat. This ability to store heat protects organisms from damaging changes in temperature

19. Properties of Water Adhesion is the attraction between molecules of one substance and molecules of another substance; adhesion makes H2O one of the best solvents http://www.youtube.com/watch?v=EBfGcTAJF4o&NR=1

20. Solutions & SuspensionsMixtures of two or more elements or compounds that are physically NOT chemically combined Solution – mixtures in which the molecules of the substances are evenly distributed between the solvent and the solute Suspension – mixture of water and nondissolved materials

21. Acids, Bases, and pHpH is a measurement of the H+ concentration in a solution Water (H2O) is a neutral molecule (neither acidic or basic) which will dissociate into and equal number of H+ and OH- and is the basis of pH comparison

22. Acids, Bases, and pHpH is a measurement of the H+ concentration in a solution The pH scale (Fig. 2-10)

23. Acids, Bases, and pHpH is a measurement of the H+ concentration in a solution

24. Acids, Bases, and pHpH is a measurement of the H+ concentration in a solution pH of water is 7 Acids have a greater [H+] than [OH-] pH is less than 7 Bases have a greater [OH-] than [H+] pH is greater than 7 Buffers are weak acids or bases that can react with strong acids or bases to help prevent sharp sudden changes in pH (maintain homeostasis)

25. Carbon Compounds Carbon compounds contain carbon and usually hydrogen; most occur naturally only in bodies & products of living things Electron Structure of Carbon

26. Characteristics of Carbon Carbon can bond with a variety of other elements Carbon can bond to other carbon molecules (Fig. 2-11) Carbon can form single, double or triple bonds Carbon can be bonded into long chains, branches, or rings

27. Macromolecules Dehydration synthesis – a reaction in which 2 molecules are bonded together by the removal of one H+ and one OH- to form H2O and another compound http://www.youtube.com/watch?v=b7TdWLNhMtM&NR=1

28. Macromolecules Hydrolysis – a reaction in which a complex molecule is broken apart into simpler molecules by the addition of H2O

29. CarbohydratesOrganic compounds of C, H, & O; ratio of H to O is always 2:1

30. Function of Carbohydrates Energy storage (Fig. 2-13) starch is stored form of sugar in plants glycogen is stored form of sugar in animals Support cellulose is found in plant cell walls chitin forms the exoskeletons of insects &arthropods CarbohydratesOrganic compounds of C, H, & O; ratio of H to O is always 2:1

31. LipidsOrganic compounds made up of C, H, & O, but much less O than carbs. Structure of Lipids – Fats are made up of 1 glycerol and three fatty acids (Fig. 2-14)

32. LipidsOrganic compounds made up of C, H, & O, but much less O than carbs. Structure of Lipids – Phospholipids are the major component of cell membranes (Fig. 7-12)

33. LipidsOrganic compounds made up of C, H, & O, but much less O than carbs. Lipids also serve as: insulation energy storage protection – organs; waxy cuticle on the surface of leaves Lipids are non-polar – will not dissolve in water

34. Nucleic AcidsDNA, RNA – compounds that contain phosphorus (P) and nitrogen (N) in addition to C, H, & O Structure of DNA – double helix – Fig. 12-7 Function of DNA – hereditary material, base pairs act as a code that determines what proteins will be made

35. Nucleic AcidsDNA, RNA – compounds that contain phosphorus (P) and nitrogen (N) in addition to C, H, & O Structure of RNA – Fig. 12-12 – single chain of nucleic acids that are involved in protein synthesis

36. Proteins Compounds that contain N as well as C, H, & O, some also contain sulfur (S) and very small amounts of phosphorus (P) Structure Fig. 2-17

37. Proteins Compounds that contain N as well as C, H, & O, some also contain sulfur (S) and very small amounts of phosphorus (P) Function Structural – cartilage, bone, muscle Hormones – chemical messengers (ex. – insulin) Antibodies – prevent disease Enzymes – speed up reactions Transport proteins are found in cell membranes

38. Chemical reactions involve the breaking of bonds in reactants and the formation of new bonds in products Reactants – elements or compounds that enter into a reaction Products – elements or compounds that are produced by a reaction Chemical Reactions & Enzymes

39. Energy in Reactions is either released or absorbed (Fig. 2-19) Energy releasing reaction – the energy stored in the reactants is greater than the energy stored in the products (usually occurs spontaneously) Energy absorbing reaction – the energy stored in the products is greater than the energy stored in the reactants (requires energy to initiate) Activation energy – energy required to initiate a reaction Chemical Reactions & Enzymes

40. Chemical Reactions & Enzymes

41. Chemical Reactions & Enzymes http://www.classzone.com/cz/books/bio_09/resources/htmls/animated_biology/unit1/bio_ch02_0052_ab_exoendo.html This link is a great review of difference between exothermic and enothermic reactions

42. Enzymes are protein catalysts that are necessary for most of the chemical reactions that occur in living cells Catalyst – substance that brings about a reaction without being changed itself; can be re-used Enzymes – lower the activation energy, energy needed to break bonds, therefore reactions can occur quickly and at normal body temps. (Fig. 2-20) Chemical Reactions & Enzymes

43. Chemical Reactions & Enzymes

44. Enzyme Actions – Fig. 2-21 Substrate – substance that enzyme acts upon Enzymes are specific for their substrates Active site – the region on the surface of an enzyme where substrate molecules attach http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_enzymes_work.html

45. Regulation of Enzyme Activity Only small amounts of enzymes are needed because each molecule is re-used Temperature – most enzymes work best at normal body temperatures pH – different enzymes work best at different ranges of pH Concentration of substrate & enzyme determines reaction rate as long as both are freely accessible to each other (up to a certain point) Chemical Reactions & Enzymes