The Chemical Level of Organization

1. The Chemical Level of Organization Unit I. Organization of the Human Body

2. Essential Concepts • Matter is composed of atoms held together by chemical bonds • During a chemical reaction, bonds are formed, rearranged, or broken • Water is the most important and abundant inorganic compound in the body • Carbohydrates, lipids, proteins, nucleic acids, and ATP are the most important organic compounds in the body

3. Chemical Elements How Matter is Organized

4. Matter

5. Chemical Elements • Matter exists in three states: • Solids • Liquids • Gases • All matter is composed of chemical elements • Elements - the building blocks of matter

6. Major Elements

7. Minor Elements

8. Trace Elements • Examples include copper and zinc • Copper works with iron to form RBCs. Keeps vessels, nerves, bones, immune system healthy. • Zinc is necessary for immunity. Helps with mitosis, interphase and healing. Needed for smell and taste.

9. Table 2.1 Main Chemical elements in the Body

10. Atomic Structure How Matter is Organized

11. Atoms • Atom – the smallest unit of matter • An element contains the same kind of atoms • Example: a pure sample of the element carbon contains only carbon atoms

12. Atomic Structure • Nucleus • Protons • Neutrons • Electron shells • Electrons

13. Figure 2.1 Two representations of the structure of an atom

14. Atomic Structure

15. Atomic Charge • The number of protons in an atom is equal to the number of electrons • Therefore, atoms have no charge • Example: Oxygen • 8 protons are balanced by 8 electrons

16. Atomic Number and Mass Number How Matter is Organized

17. Atomic Number and Atomic Mass

18. Figure 2.2 Atomic Structure of several stable atoms

19. Isotopes

20. Figure 2.3 Marieb 7E Isotopes of hydrogen

21. Ions, Molecules, and Compounds How Matter is Organized

22. Ions • Ion - forms when an atom loses or gains electrons

23. Ions

24. Figure 2.4 Ions and ionic bond formation

25. Atoms versus Ions

26. Molecules and Compounds

27. Molecules and Compounds • H2O and O2 are molecules Why is H2O a compound? Why is O2 not a compound?

28. Free Radicals • Free radical – an ion or electrically charged molecule with an unpaired electron in its outermost shell • Are extremely unstable and highly reactive • Become stable by donating or accepting electrons, which may destroy nearby molecules • Like robbers deficient in energy • Snatch energy from stable molecules to satisfy themselves • Antioxidants help inactivate free radicals

29. Figure 2.3 Atomic structures of an oxygen molecule and a superoxide molecule

30. Chemical Bonds

31. Chemical Bonds • The forces that hold together a molecule’s atoms • Chemical bonds occur between reacting atoms’ electrons

32. The Role of Electrons • Electrons are found in shells • Each shell has space for a specific number of electrons • First shell has room for two electrons • Second shell has room for eight electrons • Only the outermost valence shell is important in bonding

33. The Octet Rule • Two atoms will bond with each other if doing so leaves both with eight valence electrons • Can “get to eight” by giving up, accepting, or sharing electrons • Hydrogen has to “get to two”

34. Ionic Bonds Chemical Bonds

35. Ionic Bonds • Ionic Bond – the force of attraction that holds a cation and anion together • Formed when one atom donates an electron and another atom accepts it

36. Example of an Ionic Bond • Sodium donates an electron • Chlorine accepts the electron

37. Ionic Compounds • Most ionic compounds exist as crystals • Ionic compounds dissolve in water to form electrolytes • Positive and negative ions

38. Table 2.2 Common Ions and Ionic Compounds in the Body

39. Covalent Bonds Chemical Bonds