1. ESSENTIALS OF HUMAN ANATOMY & PHYSIOLOGY
Chapter 2
Lecture Notes

2. Matter and Energy
Matter – anything that occupies space and has mass (weight); the “stuff” of the universe
3 states of matter:
Solid
Liquid
Gas

3. Matter and Energy
Energy – the ability to do work; putting matter into motion; massless
4 forms of energy:
Chemical
Electrical
Mechanical
Radiant

4. Composition of Matter Elements – fundamental units of matter
Periodic table – lists all 112 elements, their 1 or 2 letter symbols, atomic number, and atomic weights
4 elements compose approximately 96% of the human body:
Carbon (C)
Oxygen (O)
Hydrogen (H)
Nitrogen (N)

5. Atomic Structure Atoms – building blocks of elements
Nucleus – center of every atom an contains:
Protons (p+) = positive charge
Neutrons (n0) = no charge
Outside of the nucleus contains:
Electrons (e-) = negative charge

6. Atomic Structure

7. Identifying Elements
Atomic Number – equal to the number of protons that the atom contains
Atomic Mass – the sum of the protons and the neutrons

8. Molecules and Compounds
Molecule – 2 or more LIKE atoms combined chemically
Example: H (atom) + H (atom) = H2
Compound – 2 or more DIFFERENT atoms combined chemically
Example: 4H + C = CH4 (methane)

9. Chemical Bonds and Reactions
Chemical Reactions – occur whenever atoms combine with, or dissociate from, other atoms
Atoms are united by chemical bonds
Electrons occupy energy levels called electron shells
Electrons closest to the nucleus are most strongly attracted

10. Chemical Bonds and Reactions
Each electron shell has distinct properties:
Number of electrons has an upper limit
Shells closest to nucleus fill first
Shell 1 can hold 2 electrons
Shell 2 can hold 8 electrons
Shell 3 can hold 18 electrons

11. Chemical Bonds and Reactions
Valence Shell – outermost shell that contains electrons
Bonding involves interactions between electrons in the valence shell
Full valence shells do not form bonds
Inert Elements – have complete valence shells and are stable
Rule of 8’s – atoms interact so that they will have 8 electrons in their valence shell

13. Types of Chemical Bonds
Ionic Bonds – form when electrons are completely transferred from one atom to another
Na + Cl = NaCl
Ions – are charged particles; they either donate or accept electrons
Anions = negative ions
Cations = positive ions

14. Types of Chemical Bonds
Covalent Bonds – shared electron bonding
Single covalent bonds share one electron
H + H = H2
Double covalent bonds share two electrons
O + O = O2
Hydrogen Bonds – weak covalent bond where H is attracted to negative portion of a polar molecule

15. Examples of Covalent Bonds

16. Types of Chemical Reactions
Synthesis Reaction – atoms or molecules combine and energy is absorbed for bond formation
A + B = AB
Decomposition – molecule is broken down and energy is released
AB = A + B

17. Examples of Chemical Reactions

18. Types of Chemical Reactions
Exchange Reactions – involves both synthesis and decomposition reactions. A switch is made between molecule parts and different molecules are made.
AB + CD = AD + CB

19. Biochemistry: Essentials for Life
Two major classes of molecules:
Organic Compounds = contain carbon and most are covalently bonded
Inorganic Compounds = lack carbon and tend to be simpler compounds

20. Organic Compounds
Carbohydrates – contain C, H, and O and include sugars and starches; are classified according to their size:
Monosaccharide – simple sugars
Glucose
Disaccharides – 2 simple sugars joined by dehydration synthesis or hydrolysis
Sucrose = glucose + fructose
Polysaccharides – long branching chains of linked simple sugars
starch

21. Examples of Sugars

22. Examples of Sugars

23. Organic Compounds
Lipids – contain C, H, and O; C and H outnumber O; are insoluble in water
Triglycerides (neutral fats) – found in fat deposits and are composed of fatty acids and glycerol; source of stored energy
Phospholipids – form cell membrane
Steroids – include cholesterol, vitamin D, and some hormones

24. Organic Compounds
Proteins – contain C, O, H, N and sometimes S; made up of amino acids
Account for over half of the body’s organic matter
Provides for construction materials for body tissues
Plays a vital role in cell function
Act as enzymes, hormones, and antibodies
Enzymes = act as biological catalysts which increase the rate of chemical reactions

25. Organic Compounds
Nucleic Acids – provide the blueprint for life; make DNA and RNA and are composed of nucleotide bases:
Adenine
Guanine
Cytosine
Thymine – found only in DNA
Uracil – found only in RNA
DNA = DeOxyRiboNucleic Acid – provides instruction for every protein in the body
RNA = RiboNucleic Acid

26. DNA

27. Organic Compounds
Adenosine TriPhosphate (ATP) – chemical energy used by all cells; energy is released by breaking high energy phosphate bonds and producing ADP

28. Inorganic Compounds H2O (water) – most abundant inorganic compound
Salts – easily dissociate into ions in the presence of water and they are vital to many body functions; include the electrolytes which conduct electrical currents

29. Inorganic Compounds
Acids – are proton donators; can release detectable H ions; have a sour taste and can dissolve many metals or “burn” holes in materials
Bases – are proton acceptors; have a bitter taste and feel slippery
Neutralization Reaction = acids and bases react to form water and a salt

30. pH Measurements pH = measures relative concentrations of H ions
pH 7 = neutral
pH < 7 = acidic
pH > 7 = basic
Buffers = chemicals that can help regulate pH change