7th grade notes

Chapter 3 - Section 1 Chemical Compounds in Cells


I. Chemical Compounds in Cells   

A.  ElementsAn element is any substance that cannot be broken down into simpler substances.  The smallest unit of an element is an atom.         Example of an element is carbon.    

  B.  Compounds         A compound is two or more elements that are chemically combined.         The smallest unit of a compound is a molecule.         An example of a compound is water.     

C.  Organic and Inorganic Compounds         Inorganic compounds do not contain carbon.          Organic compounds contain carbon and hydrogen and usually are associated with living things.

 Four groups of Organic Compounds

 Lipids Proteins Nucleic Acids
Made of the elements carbon, hydrogen, and oxygenMade of the elements carbon, hydrogen, and oxygenMade of the elements carbon, oxygen, hydrogen, nitrogen,and sulfurMade of the elements carbon, oxygen, hydrogen, nitrogen, and phosphorus
Supply energy for cell processes, form plant structures; short-term energy storageStore large amounts of energy long term; form boundaries around cellsRegulate cell processes and build cell structuresCarry hereditary information; used to make proteins
Sugars-fruits, starch-pasta, and cellulose-found in cell walls of plantsFats, oils, waxes, phospholipids, and cholesterolEnzymes, skin, and hairDNA and RNA