1. Principles of Chemistry
Chapter 2
Basic Biology

2. The Nature of Matter
Matter is anything that occupies space and has mass.
Elements are the simplest pure substances.
Compounds are made of two or more elements chemically combined.
Mixtures are made of two or more substances, physically mixed together, that retain their own properties.

3. Matter Matter can exist in three states: gas, liquid, or solid.
A gas has no definite shape or volume.
A liquid has a definite volume, but no definite shape.
A solid has a definite shape and volume.

4. Energy
Energy is massless & does not take up space & is measured by its effects on matter.
Work is an evidence of energy: it is force applied on an object over a distance.
Energy is defined as the ability to do work or to put matter into motion.
There are four forms of energy:
Chemical: stored in bonds of chemicals
Electrical: movement of electrons
Mechanical: moving matter
Radiant: waves of the electromagnetic spectrum

5. Forms of Energy There are two types of mechanical energy:
Kinetic: energy doing work
Potential: stored energy
Energy can be easily converted from one form to another.
In the body, chemical energy from food is converted to ATP in the cell and used to produce electric energy (nerve impulse) and mechanical energy (muscle contraction).

6. Elements
All matter is composed of a limited number of pure substances called elements.
Elements cannot be broken down into simpler substances by chemical means.
Each element is composed of a unique atom.
Elements are arranged in a periodic table, according to their atomic numbers and reactive characteristics.

7. Atoms Atoms are the smallest unit of an element.
They can exist alone or in combination with other elements.
Atoms are made of three basic subatomic particles: electrons, protons, and neutrons.
Subatomic particles can be distinguished by their location in the atom, their charge and mass.

8. Subatomic Particles
Protons are located in the nucleus or center of the atom, they have a positive charge and make up half the atomic mass.
Neutrons are also in the nucleus, have no charge (are neutral), and make up the other half of the atomic mass.
Electrons are found in shells or layers around the nucleus, have a negative charge and no measurable mass.

9. Identifying Elements
Every element has a specific atomic mass, atomic number and atomic symbol.
The atomic mass is the combined mass of protons and neutrons.
The atomic number is the number of protons in each atom of an element.
The atomic symbol is a one, two or three letter combination used to represent the element.

10. Chemical Compounds
The molecule is the basic structural unit of a compound & sometimes an element.
Some elements, such as oxygen, are found as atoms bonded together, in a diatomic molecule.
The molecular formula tells the specific number and arrangement of atoms in a compound.
Ex. Glucose, C6H12O6 , & fructose molecules both have the same formulas & are isomers.

11. Atomic Energy Levels
The electrons orbiting the nucleus move at very high speeds in a number of different energy levels.
The number and arrangement of the electrons in an atom’s outermost shell is responsible for how an atom reacts with other atoms.

12. Atomic Energy Levels
Each energy level has a specific number of electrons it can hold.
1st Energy Level = 2 electrons
2nd Energy Level = 8 electrons
3rd Energy Level = 8 or 18 electrons
Atoms with full outer energy levels do not attract or transfer electrons (or react) and are considered stable.
Atoms without full outer energy levels will transfer or attract electrons until a full outer energy level is obtained.

13. Chemical Bonding
A chemical bond is formed when electrons are transferred or shared between two or more atoms.
The two types of bonds are covalent and ionic.

14. Ionic Bonds An ion is a charged atom.
When electrons are transferred an imbalance of charges occurs and an ion is formed.
Ionic bonds form between oppositely charged ions, when electron(s) are transferred between them.
Positively charged ions are called cations.
Negatively charged ions are called anions.

15. Covalent Bonds
Compounds formed by the sharing of electrons have covalent bonds.
In a covalent bond, each atom of the pair shares an electron with the other.
The shared pair of electrons orbit the nuclei of both atoms.
Single (2), double (4) and triple (6) covalent bonds can be formed between atoms.

16. Hydrogen Bonds
Hydrogen bonds are extremely weak bonds that form when a hydrogen atom bound to a nitrogen or oxygen atom is attracted to another oxygen or nitrogen atom (so between molecules).
Hydrogen bonding is common between water molecules & is the reason for water’s surface tension & high heat of vaporization.
Hydrogen bonding is essential in maintaining the structure of protein molecules.

17. Isotopes
Although all atoms of an element have the same number of protons, the number of neutrons can vary, this is called an isotope.
Isotopes have the same atomic number, but different atomic masses due to different #s of neutrons.
Some isotopes are radioactive and are used as tools in the treatment and diagnosis of disease.

18. Inorganic Compounds
Inorganic compounds lack carbon and tend to be small, simple molecules.
Important inorganic compounds include:
Water
Salts
Acids
Bases

19. Organic Compounds
Organic (or biomolecular) compounds are formed by living things & consist of different combinations of the elements hydrogen, oxygen, nitrogen and carbon.
All organic compounds contain carbon.
Biomolecular compounds can be broken down into four groups: Carbohydrates, lipids (fats), proteins, and nucleic acids.

20. Water Water is the most abundant inorganic compound in the body.
Its properties are a result of being a polar covalent molecule with lots of H bonding between molecules.
It has many important properties:
High heat capacity
Polarity/solvent properties
Chemical reactivity
Cushioning and Transparency
Great solvency – called the universal solvent

21. Salts
All salts are electrolytes, substances that can conduct an electric charge.
The salts of many metal elements are found in the body including calcium and phosphorous in the bones and teeth.
Salts are easily ionized in water and are able to perform vital functions for the body including transmitting nerve impulses and regulating amount of water in the bloodstream.

22. Solutions, Suspensions & Colloids
Solutions are liquid mixtures where the minor part (solute) is uniformly distributed within the major part (solvent).
Suspensions occur when small particles are dispersed throughout a gas or liquid. If undisturbed, particles will settle. Particles in a suspension are larger than those in a colloid or solution.
A colloid is a combination of mixed molecules that will not settle out or join with the other substance.
This video shows good examples & explanations of these different types of colloidal mixtures.

23. Acids Acids are electrolytes w/a sour taste & can dissolve metal.
Acids release large amounts of H ions.
Acids are important in the process of digestion & in maintaining the body’s pH levels.
The pH scale is a measure of H+ ion concentration of a solution. The scale ranges from 1 to 14 where low pH solns are acidic.

24. Bases
Bases (or alkalines) are electrolytes that have a bitter taste, have low H+ concentrations, and produce hydroxide ions (-OH).
Bases have a high pH(8-14). A pH of 7 is neutral.
Bases play an important role in maintaining the body’s pH levels, especially around the red blood cells.

25. Chemical Reactions
A living thing’s metabolism is made of the sum of all chemical reactions that occur within.
Reactions involve chemical bonding changes in substances that chemical combine.
Those substances that enter into a reaction are called reactants.
The resulting substances are called products.

26. The 4 major Macromolecular Nutrient Groups: Carbohydrates
Carbohydrates are a source of energy for the cell.
They consist of sugars and starches.
Ex. Glucose which is present in the fluid surrounding the cell
Carbohydrates are made of oxygen, hydrogen and carbon.

27. Lipids (Fats & Oils)
Lipids are formed from fatty acids and glycerol molecules.
Lipids store and supply energy for the body when needed.
A special characteristic of lipids is that they are insoluble in water.
Lipids are used in cell membranes for their ability to keep regulate water in and out of the cell.

28. Proteins Protein molecules are made up of large chains of amino acids.
Proteins are the structural molecules of the cells and the chemical compounds that control biological reactions in the body.
Proteins that control metabolic functions are called enzymes.

29. Nucleic Acids
Ribonucleic acid (RNA) and Deoxyribonucleic acid (DNA) are the last group of organic compounds.
RNA is responsible for protein synthesis.
DNA is responsible for the formation of protein molecules and carries hereditary information.

30. Adenosine Triphosphate (ATP)
This is a nucleic acid molecule and is made by the mitochondria in eukaryotic cells.
The synthesis of ATP provides the storage of chemical energy for all body cells.
ATP is made of an adenine base, a ribose sugar, and three phosphate groups.
The energy is stored when a phosphate group bond is formed and released when the phosphate bond is broken.