1-UNIT-B.-Chemistry-of-Life.pdf

The Chemistry of Life AP Biology 2007-2008  What level of organization are we now on? atom molecule compound organ tissue cell Organ organism system AP Biolog...

The Chemistry of Life AP Biology 2007-2008  What level of organization are we now on? atom molecule compound organ tissue cell Organ organism system AP Biology  Everything is made of matter  Matter is made of atoms Hydrogen 1 proton 1 electron Oxygen 8 protons 8 neutrons 8 electrons AP Biology Proton + Neutron 0 Electron –  What are atoms made of?  Each atom is made of protons, neutrons and electrons  Protons are positively charged particles  Neutrons are neutral (they have no charge)  Electrons are negatively charged particles AP Biology  Why are electrons important?  two atoms connect to each other through the interaction of the electrons – – AP Biology  Life requires ~25 chemical elements  About 25 elements are essential for life  Four elements make up 96% of living matter: carbon (C) hydrogen (H) oxygen (O) nitrogen (N)  Four elements make up most of remaining 4%: phosphorus (P) calcium (Ca) sulfur (S) potassium (K) AP Biology  What is a compound?  A compound is a substance made up of atoms of two or more different elements. This example is carbon dioxide Molecules are made of atoms. Compounds are types of molecules! AP Biology    Both atoms are holding on  Very stable and forms MOLECULES! Covalent bond  More than one pair of elections = double and triple bonds… VERY – STRONG! –  CARBON forms ORGANIC MOLECULES AP Biology H2 (hydrogen gas)  What is an example of Hydrogen bonding in biology?  A hydrogen bond is a weak chemical bond. * The strands of DNA are bonded by hydrogen bonds AP Biology  Why do we need to know about BONDS??  Think back to levels of organization: when we start with an atom and go to a compound what is happening in between the arrows?  To go from an atom to an organism, bonding must occur! For example, BONDS form molecules from atoms… like WATER! AP Biology   The water content is greatest in young cells and decreases with age.  About 70% of your total body weight is water and about 95% of jellyfish and some plants is water! AP Biology measuring pH of something.  What are organic molecules?  All organic molecules contain carbon.  Inorganic molecules do NOT contain carbon (Ex: H2O)  There are three main elements that are present in all living things:  CARBON  OXYGEN  HYDROGEN AP Biology   Because of its unique ability to combine in many ways with itself and other elements, carbon has a central role in the chemistry of living organisms AP Biology Carbon Atoms and Bonding Carbon atoms can form single, double or triple bonds with other carbon atoms. Carbon can form up to 4 bonds This allows carbon atoms to form long chains, almost unlimited in length. Carbon can bond with other carbons, form straight chains, branched chains and rings  The Chemistry of Carbon “organic”: must contain at least one carbon. CH4 = simplest organic molecule Carbon has 4 valence electrons Therefore, carbon will always make 4 bonds with other atoms Ability to form millions of different compounds with other elements  What are biomolecules?  Large Organic molecules that exist in all living things  Also known as Macromolecules (Macro=Large)  They are life's building blocks  All living things are formed from these molecules AP Biology  Biomolecules are complex, but are made up of simpler components AP Biology  Biomolecules  Biomolecules start out small as monomers and you add on to them to build them up to become polymers SMALL TO BIG Mono= One Poly= Many AP Biology