2.  Proteins have many different functions in the body  Structure – proteins help provide structure and support, make up muscles and bones

3.  Transport – some proteins help to carry things around the body or into and out of cells

4.  Hormones – messenger proteins that carry signals throughout your body  Enzymes – proteins that help with chemical reactions  Antibodies – proteins that help protect the body from infection

5.  Proteins can have up to 4 levels of organization ◦ Primary ◦ Secondary ◦ Tertiary ◦ Quaternary

6.  Primary protein organization = the initial chain of amino acids  Peptide bond – the bond between amino acids to form the long chain we call a protein

7.  Secondary structure consists of two shapes ◦ Alpha helix ◦ Beta sheets  Caused by hydrogen bonding

8.  Three dimensional structure of a single protein molecule  Caused by hydrophobic interactions

9.  3D structure with multiple protein subunits  Held together by disulfide bonds

10.  Some proteins help to control reactions and cell processes  Enzyme – Specific proteins that can speed up reactions

11.  Energy can be either released or absorbed whenever chemical bonds form or are broken  Living things carry out chemical reactions that require energy  Organisms need a source of energy ◦ Plants have the sun ◦ Animals eat food

12.  Activation energy – the energy needed to start a chemical reaction

13.  Remember!  Some reactions give off energy…and some absorb energy!

14.  Chemical reactions that release energy often occur spontaneously  Chemical reactions that absorb energy won’t happen without an input of energy

15.  Draw two energy reaction graphs in your notes!

16.  Catalyst –a substance that speeds up the rate of a reaction  Catalysts lower activation energy  Enzymes are biological catalysts! They help speed up chemical reactions in your body!

18.  Enzymes are very specific!  A single enzyme usually only works with one type of reaction  HINT: The name of an enzyme usually has something to do with reaction it works with  Enzymes almost always end with –ase!!!

19.  Each enzyme will combine with only a specific molecule  Substrate – the molecule an enzyme binds to in a reaction  We call this the “lock and key model”

20.  Like a key in a lock…each enzyme fits only one substrate molecule

22.  Enzymes are picky…they only like to work under certain conditions  Each enzyme is designed to work in a certain temperature range  Enzymes in your body work best at 37 ºC

24.  pH also plays a role on enzyme activity  Enzymes in your stomach work best at a pH of around 2  Each enzyme works best at a specific pH level ◦ Most around 7.4 …Why?

26.  What type of molecule are enzymes?  Proteins  Proteins are made up of what type of molecules?  Amino acids

27.  The amino acids that make up proteins and enzymes are held together by which type of bond?  Peptide bond

28.  How do enzymes help speed up a chemical reaction?  Lower the reactions activation energy  What are two things that can change how well an enzyme works?  Temperature and pH

29.  Each enzyme works on one particular substrate  “Lock and Key Model”

30.  Enzymes aren’t used up!  Once the reaction is done, the enzyme is left unchanged and can continue its job  So enzymes are reusable!

31.  pH and Temperature have an effect on enzyme activity  Denature – when a protein loses its shape and can no longer work  http://www.sumanasinc.com/webcontent/ani mations/content/proteinstructure.html http://www.sumanasinc.com/webcontent/ani mations/content/proteinstructure.html