General Chemistry Review for the biological sciences

Why Chemistry??????? Hey…this is Biology! Why do we need to know about chemistry?? All living things are made up of Atoms Molecules Chemicals We need to know how chemicals interact to be able to understand biology!

Chemical Elements Each element consists of unique atoms Represented by symbols—H, Na, Au, etc. A total of 118 named elements #’s 1 through 92 are naturally-occurring 93+ are synthetic

Chemical Elements 92 naturally occurring elements About 25 are considered essential to life 4 make up > 95% of living matter Carbon Hydrogen Oxygen Nitrogen

Atoms The smallest particle of an element that has the qualities of that element Made up of smaller sub-atomic particles Cannot be broken down into simpler substances by ordinary means

molecules Atoms of two or more different types chemically combined in a fixed ratio Chemically different than the atoms that make them up Lots of molecules of the same kind are a compound A molecule is the smallest part of a compound that acts like the compound

a water molecule H2O Hydrogen: a colorless, odorless gas; explosive! water: a colorless, odorless liquid (at ordinary temps); necessary for life H2O Hydrogen: a colorless, odorless gas; explosive! oxygen: a colorless, odorless gas; supports combustion

So…how are atoms held together in a molecule? CHEMICAL BONDS! Ionic: the giving and taking of electrons Covalent: the sharing of electrons Hydrogen: the attraction of + and -

Ionic Bonds Exchange of electrons Forms charged particles called ions One atom takes electrons & the other donates them Forms charged particles called ions ex—sodium chloride

Covalent Bonds Sharing of electrons Between nonmetals Cl + Cl CH4 Non-polar Polar

Covalent Bonds non-polar polar Equal sharing of electrons between two or more atoms Carbon, Hydrogen CH4 C2H6 Unequal sharing of electrons between atoms Forms polar molecules Water, sugar, alcohol

Hydrogen bonds The attraction between the +charged portion of one polar molecule and the –charged portion of another molecule Found in water, proteins, DNA

Biomolecules or Macromolecules Polymers produced by living things Polymers are Large molecules made up of smaller, repeating units called monomers

Polymer Carbohydrates Lipids Proteins Nucleic acids monomers examples Starches, cellulose, Pasta, potatoes, etc. Fats, oils, waxes Meat, muscle tissue, enzymes, hair, etc. DNA & RNA Simple sugars Glycerol & fatty acids Amino acids nucleotides Carbohydrates Lipids Proteins Nucleic acids

Glucose molecule X 100’s starch molecule

the awesomeness continues… Enzymes!! the awesomeness continues…

Classifying Enzymes There are 4 major categories of macromolecules: carbohydrates, lipids, proteins, & nucleic acids

Almost all enzymes are proteins. However, there are a few catalytic RNA molecules. proteins Image: Levels of protein structure, M Ruiz

Naming Enzymes For many enzymes, take the name of the substrate the enzyme works on and add the suffix -ase Example: Lactose  Lactase

Enzymes are Catalysts Enzymes speed up chemical reactions. Enzymes allow reactions to happen that otherwise could not occur. Enzymes are very specific! Enzymes are catalysts to over 4000 biochemical reactions! http://en.wikipedia.org/wiki/File:GLO1_Homo_sapiens_small_fast.gif

Enzymes change other molecules Starch synthase (the enzyme) puts glucose molecules together into a chain = starch Amylase (a different enzyme) breaks down starch into glucose molecules These processes (using different enzymes) occur with all of the macromolecules

Enzymes are Reusable enzymes are reusable molecules found in living things. as a result, they do not get used up in the reaction http://en.wikipedia.org/wiki/File:GLO1_Homo_sapiens_small_fast.gif

Enzyme Form and Function Lock & key Model: The shape of an enzyme allows it to do a specific job much like a lock and key.

Induced Fit Model An enzyme can form to the shape of its substrate. http://en.wikipedia.org/wiki/File:Induced_fit_diagram.svg

Why are enzymes so important? Nearly all chemical reactions in biological cells require enzymes to make the reaction occur in a reasonable amount of time at biological temperatures at biological pH’s

Enzymes are used all over your body! http://en.wikipedia.org/wiki/File:Digestive_system_diagram_en.svg

THE END