Chemistry & Carbon The Cellular Basis of Life

Atomic Structure  Elements: smallest unit a substance can be broken down into and still have the same chemical properties naturally occurring elements of the 92 are essential to life 3. carbon, nitrogen, hydrogen, & oxygen are important 4. trace elements are required by an organism in very small amounts

Atomic Structure Continued  Atom: smallest form of an element, made up of …. 1. proton – positive charge; in nucleus 2. neutron – no charge; in nucleus 3. electron – negative charge; outer energy level (only 2 e-’s can occupy the same orbital)

Atomic Structure  Compound: 2 or more elements combined in a fixed ratio  Atomic Number: # of protons  Mass Number: # of protons + # of neutrons  Isotopes: atoms of the same elements with different numbers of neutrons  Ion: negatively charged particle

Bonding & Electrons  Atoms want to fill their outer energy level to b/c stable  Electrons have energy  the further from the nucleus, the more energy e- ’s have  As e-’s move to higher energy levels, energy is ADDED to them  As e-’s move back down energy levels, energy is LOST or RELEASED

Chemical Bonding Types of Chemical Bonds Ionic Bond Covalent Bond Hydrogen Bond Non-polar Covalent Bond Polar Covalent Bond

1) Ionic Bonds  Definition: attraction of oppositely charged ions;  Lose and gain electrons  Ex. Na+ + Cl-  NaCl  The Na+ gives up one electron & the Cl- gains one electron  Easier to break than covalent bonds

1) Ionic Bonds

2) Covalent Bonds  Definition: two atoms share electrons; strong bond Non-polar Covalent Bond: electrons are shared equally Ex. Hydrocarbon chains

2) Covalent Bonds Continued  Polar Covalent Bonds: electrons are shared unequally due to electronegativity; strong bond Ex. Water

3) Hydrogen Bonds  Definition: when electrons b/w hydrogen and other atoms are shared unequally  Hydrogen has a partial positive charge  Hydrogen is attracted to slightly negatively charged atoms  Advantage: briefly together, respond & separate

4) Van der Waals Interactions  Definition: weak electric forces that attract neutral molecules to one another; Ex - A non-polar molecule with areas that are positively and/or negatively charged These areas allow them to “stick” to another molecule or area of a molecule  Weak force

Weak Bonds  Examples of Weak Bonds are: 1. Hydrogen 2. Ionic 3. Van der Waals Forces  Advantage is…. 1. Holds a 3-D molecule in it’s correct shape 2. may form b/w molecules 3. may form b/w regions of a single molecule

Strong Bonds  Examples of strong bonds are: 1. Polar covalent 2. Non-polar covalent  Advantage is…. 1. bonds do not easily break 2. these bonds hold together living organisms in adverse situations

Carbon & Organic Chemistry  Carbon  6 protons, electrons, & neutrons  What type of bond will it form? Why?  Carbon always wants to have ____ bonds  Other elements  Element# of Bonds Nitrogen Oxygen Hydrogen

Types of Isomers  Structural Isomer: differ in structural arrangement of their atoms  Geometric Isomer: differ in spatial or 3-D arrangements  Stereoisomers: mirror images of each other Ex. Thalidomide

Structural Isomer

Geometric Isomer

Stereoisomer

Functional Groups & Behavior  Chemical groups attached to the carbon skeleton of a molecule Determine the “behavior”or properties of the molecule Ex – Hydroxyl =‘s polar behavior = will bond with other polar molecules Ex – Methane =‘s nonpolar behavior = will bond with other nonpolar molecules

Functional Groups Functional GroupFormula Hydroxyl or Alcohol-OH Carboxyl-COOH Amino-NH 2 Ketone & Aldehyde-CO & -CHO Phosphate-PO 4 Sulfhydryl-SH

Monomers Link to Make Polymers

How are Polymers Made from Monomers?  Dehydration Synthesis Aka, condensation reactions Links monomers together by removing water H (from one monomer) and OH (from another monomer combine to form water

How are Polymers broken back down into monomers?  Hydrolysis Breaking a polymer into many monomers by adding water

Dehydration Synthesis & Hydrolysis