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. How Matter is Organized
Chemical Elements
Students will use their text and Handout 4 to meet learning outcomes 1-4.
How Matter is Organized

4. Matter Matter anything that occupies space and has mass Mass
the amount of matter in an object; constant
Mass
The force of gravity on an object; variable
Weight

5. Chemical Elements Matter exists in three states:
Solids
Liquids
Gases
All matter is composed of chemical elements
Elements - the building blocks of matter
Solids (bones and teeth) are compact and have definite shape
Liquids (blood plasma) have a definite volume and assume the shape of the container they are in
Gases (oxygen and CO2) don’t have a definite volume or shape

6. Major Elements Carbon Hydrogen Oxygen Nitrogen
26 chemical elements are normally found in the human body
4 are the major elements that make up 96% of the body’s mass

7. Minor Elements Calcium Chlorine Phosphorus Magnesium Potassium Iodine
Sulfur
Sodium
Chlorine
Magnesium
Iodine
Iron
These minor elements make up about 3.6% of the body’s mass

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.
There are about of them that only add up to 0.4% of the body’s mass
Functions of some trace elements is unknown

9. Table 2.1 Main Chemical elements in the Body

10. How Matter is Organized
Atomic Structure
Students will use their text and Handout 4 to meet learning outcomes 1-4.
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
In the cloud model, the shading represents the chance of finding an electron outside the nucleus – not contained

14. Atomic Structure Protons Positively charged particles Neutrons
Neutrally charged particles
Neutrons
Negatively charged particles
Electrons

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. How Matter is Organized
Atomic Number and Mass Number
Students will use their text and Handout 4 to meet learning outcomes 1-4.
How Matter is Organized

17. Atomic Number and Atomic Mass
the number of protons in an atom’s nucleus
Atomic number
the sum of the number of protons and neutrons in an atom’s nucleus
Mass number
Atomic mass
Dalton = amu
Neutron = daltons
Proton = daltons
Electron = dalton = 2000 times smaller than a neutron or proton

18. Figure 2.2 Atomic Structure of several stable atoms
The largest element in the human body is iodine with 53 electrons – 2,8,18,18,7

19. Isotopes
atoms of an element that have different numbers of neutrons and therefore different mass numbers
Isotopes
unstable isotopes that emit radiation as they decay
Radioactive isotopes

20. Figure 2.3 Marieb 7E Isotopes of hydrogen
Deuterium is a stable isotope of Hydrogen with double the atomic mass – known as heavy hydrogen
Found in the oceans and in stars

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

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

23. Ions An atom that has lost electrons Positively charged Cation
An atom that has gained electrons
Negatively charged
Anion

24. Figure 2.4 Ions and ionic bond formation
02_01

25. Atoms versus Ions Atoms Ions Equal number of protons and electrons
Unequal numbers of protons and electrons
Uncharged
Charged

26. Molecules and Compounds
Forms when two or more atoms share electrons
Molecule
A type of molecule composed of two or more different atoms
Compound

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
02_01

30. Students will use their text and Handout 5 to meet learning outcomes 5 and 6.
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
Most ions in the body are dissolved in body fluids as electrolytes
Named for the ability of the solutions to conduct electricity

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

39. Covalent Bonds
Chemical Bonds