1. The Chemical Level of Organization

2. What is matter?
It is anything that takes up space and has mass (weight).
Types
Solids – definite shape and volume
Liquids – definite volume
Gases – no definite shape and volume
Changes
Physical changes – do not change the basic nature of a substance (ice melting)
Chemical changes – change the composition of a substance (food digestion)

3. What is the composition of matter?
Elements – unique substance that cannot be broken down into simpler substances (112 in existence)
Four Common Elements (96% of body)
Carbon
Oxygen
Hydrogen
Nitrogen

4. What is an atom?
It is the building block of elements shown by one or two letters found on a periodic table
Structure
Protons – positively charged
Electrons – negatively charged
Neutrons – no charge

5. Atomic Vocabulary
Molecules – two or more atoms that combine chemically (H2O)
Compound – two or more different atoms bind together to form a molecule (CH4)
Chemical reactions – when atoms unite chemically forming chemical bonds

6. What are chemical bonds?
It is an energy relationship that involves interactions between the electrons of the reacting atoms.
The valence shell or outer energy level is involved in this bonding.
First energy shell – holds 2 electrons
Second energy shell – holds 8 electrons
Third energy shell – holds 8 electrons

7. What are two types of chemical bonds?
Ionic bond – when electrons are completely transferred from one atom to another. This forms two oppositely charged ions (+ and -)
NaCl – sodium chloride (table salt)
Na = (11p+,12n0,11e-)
Cl = (17p+,18n0,17e-)

8. Type of chemical bond
2. Covalent bond – sharing of electrons between atoms
CH4 (methane), H2 (hydrogen gas), Cl2 (chlorine gas)

9. What is energy?
It is the ability to do work or to put matter into motion.
Types
Kinetic energy – actually doing work (moving objects)
Potential energy – inactive or stored energy (batteries)

10. What are the energy forms?
Chemical energy – stored in chemical substances
Electrical energy – movement of charged particles
Mechanical energy – moving matter
Radiant energy – travels in waves

11. What are inorganic compounds?
Compounds that lack carbon
Three Types:
Water – most abundant compound in body and universal solvent
Salts (electrolytes) – nerve transmission, muscle contraction, blood clotting and metabolism
Acids – proton donors (H+)
Bases – proton acceptors (OH-)

12. What is pH?
It is the concentration of hydrogen and hydroxide ions in various body fluids. The scale runs from 0 to 14.
pH below 7 = acidic
pH above 7 = basic or alkaline
pH at 7 = neutral

13. pH scale

14. What are organic compounds?
Carbon-containing compounds
Contains the four elements – carbon, hydrogen, oxygen, and nitrogen (CHON)
Major Types:
Carbohydrates
Lipids
Proteins
Nucleic acids

15. What are carbohydrates?
Sugars and starches
Contain carbon, hydrogen, and oxygen
Classification:
Monosaccharides – simple or one sugar
(glucose)
b) Disaccharides – double sugars (sucrose, lactose, maltose)
c) Polysaccharides – long branching sugars ( starch and glycogen)

16. What are lipids?
Neutral fats or triglycerides (glycerol and three fatty acid chains) – most abundant source of energy
Phospholipids – found in cell membrane
Steroids (cholesterol) – found in cell membrane

17. What are proteins? 50% of organic matter in body
Building blocks are amino acids (20)
Classification:
Fibrous proteins or structural proteins (collagen and keratin)
Globular proteins or functional proteins (enzymes, hemoglobin, and hormones)

18. What are nucleic acids Building block is nucleotide
Nitrogenous base
Sugar (ribose or deoxyribose)
Phosphate group
Deoxyribonucleic acid (DNA) – genetic material of the cell nucleus
Ribonucleic acid (RNA) – directs protein synthesis

19. Nucleic Acid Diagrams
nucleotide
DNA structure

20. What are enzymes? Functional proteins that act as biological catalysts
Increase rate of chemical reaction
End with the suffix (ase)

21. What is ATP? Adenosine triphosphate Chemical energy for all body cells
Structure:
Adenine base
Ribose sugar
Three phosphate groups