AP Biology

 Carbon: The backbone of Life?  Wait, what? Isn’t it water?  Well yes and no.  Water is the universal medium for life  Most living organisms are made up of chemicals that are based on the element carbon

 Carbon enters the biosphere through the action of plants  Plants use solar energy to transform atmospheric CO2 into the molecules of life  Molecules are then passed to animals that feed on plants

 Carbon is able to form molecules that are large, complex and diverse  It makes possible the diversity of organism that have evolved on earth

 1800’s: Theory of vitalism  A belief that a life force outside of the jurisdiction of physical and chemical laws  1950’s: U.S. Stanley Miller. Theory of mechanism  The view that physical and chemical laws govern all natural phenomena including the processes of life.

 In order to prove that spontaneous life could occur, he did an experiment  Primordial soup idea went from speculation to empirical science!

 Methane, ammonia, and hydrogen and subjected it to steam  It was then exposed to an electrical charge  This caused a chemical reaction  The result: proteins and amino acids

 Carbon has 6 electrons  Carbon usually shares its electrons to complete the valence shell  Creates covalent bonds  Each carbon atom acts as an intersection point and can branch off in as many as four directions  This allows carbon to form complex bonds.

 Methane  Ethane  Ethylene

 Balloon  40 ml of water  Soft drink bottle  Drinking straw  Lemon juice or vinegar  1 teaspoon baking soda

 Stretch out the balloon  Pour 40 ml of water into the soft drink bottle  Add the teaspoon of baking soda and stir it around with the straw till it is dissolved  Pour the vinegar or lemon juice in and quickly put the stretched balloon over the bottle

 If all goes well then your balloon should inflate! Adding the lemon juice to the baking soda creates a chemical reaction. The baking soda is a base, while the lemon juice is an acid, when the two combine they create carbon dioxide (CO2). The gas rises up and escapes through the soft drink bottle, it doesn't however escape the balloon, pushing it outwards and blowing it up. If you don't have any lemons then you can substitute the lemon juice for vinegar.