1. Introduction to Cell Biology
Dynamics of Life
Ch. 6 The Chemistry of Life, pages
October 31 – November 1

2. Building Block Units Atoms
Elements
Pure substance that makes up everything
Names of elements are abbreviated using symbols
6 most common elements in living things are:
Sulfur (S), Phosphorus (P), Oxygen (O), Nitrogen (N), Carbon (C), Hydrogen (H)
Atoms
smallest particle of an element that has the characteristics of that element, basic building blocks of all matter
Contains a nucleus that holds positively(+) charged protons and neutral neutrons
Around the nucleus are the energy levels where negatively (-) charged electrons spin around the nucleus
first energy level holds up to 2 electrons
second energy level holds up to 8 electrons
third energy level holds up to 8 electrons

3. Building Block Units Continued
Atoms of different elements have different numbers of protons (Exception)
Isotopes: atoms of the same element with different numbers of neutrons
Some isotopes are radioactive and are useful in experiments
Compound
Substance made up of 2 or more elements chemically combined (covalently bonded)
Table salt is made up of chlorine and sodium
States of Matter
A gas is a state of matter in which atoms or molecules have enough energy to move freely.
A liquid is a state of matter in which atoms or molecules are constantly in contact but have enough energy to keep changing positions relative to one another.
A solid is a state of matter in which atoms or molecules do not have enough energy to move.

4. Bonding Elements
Ionic Bond
Covalent Bond
formed when one atom donates electrons to another atom
formed when two atoms share electrons
Molecule is a compound held together by covalent bonds

5. Chemical Reactions
A chemical reaction is a process that changes some chemical substances into other chemical substances. The substances that start a chemical reaction are called reactants. The substances that form as a result of a chemical reaction are called products. During the reaction, the reactants are used up to create the products.
Metabolism: all the chemical reactions that occur in an organism
Water helps facilitate (aid) chemical reactions in biotic organisms due to its chemical structure

6. Water Water (H2O) is a molecule that contains covalent bonds
Water is polar, which means there is a positive end and a negative end – can be reactive depending on pH
Water will gravitate/interact with other molecules
When water gives off hydrogen (H+) it will interact with polar molecules and break them apart into smaller molecules or compounds
When water (H2O) is –OH, it will attract hydrogen (H+) from molecules and help create larger molecules
Properties
Water heats up and cools down very slowly
Helps cells maintain homeostasis
Water expands when it freezes
So ice is less dense than liquid water and ice floats

7. Water Continued
Water transports molecules and elements in a cellular environment as a result of diffusion
Diffusion: the movement of particles from an area of high concentration to an area of lower concentration
Brownian motion: random motion of atoms and molecules
Brownian motion causes diffusion
Example: Smell of cookies moves from the kitchen (high concentration) to the rest of the house (low concentration)
Biological example: materials diffuse into and out of cells as particles will continue to move until they have reached equilibrium (are evenly spread out)

8. Macromolecules Organic compounds
Compounds that contain carbon atoms bonded to each other
Found in all living things
Carbon is important because it can bond to other atoms in so many ways
Four different types of organic compounds (macromolecules – polymers)
Carbohydrates
Lipids
Proteins
Nucleic Acids

9. Carbohydrates made up of carbon, hydrogen, and oxygen
Sugars used by organisms for short term energy
monosaccaride: 1 sugar molecule, such as glucose (monomer)
disaccharides: 2 sugar molecules linked together, such as sucrose (table sugar)
polysaccharides: many sugar molecules linked together, such as starch

10. Lipids
made up of carbon and hydrogen mostly fats, oils, waxes, steroids used by organisms for long term energy, insulation, and protective coatings
fatty acid: a simple lipid molecule (monomer)
fatty acids are linked together to make bigger lipid molecules

11. Proteins
Made up of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur.
20 different amino acids (monomer) are used to build proteins
used for construction of organisms (hair, nails, muscles),
digest food and for speeding up chemical reactions in an organism (enzymes)

12. Nucleic Acid
Made up of carbon, hydrogen, oxygen, nitrogen, and phosphorus
Nucleotides (monomer) are used to build nucleic acids
Store genetic information (DNA, RNA)