Chapter 1

 Element – a substance that cannot be broken down into simpler substances – smallest unit of an element is an atom  Compound – two or more elements that are chemically combined – smallest unit is called a molecule  Water – most chemical reactions in cells would not take place without water  Inorganic compounds – does not contain carbon  Organic compounds - contain the element carbon – carbohydrates, lipids, proteins, nucleic acids

 Two-thirds of your body’s mass is water.  67% has water inside cells and rest surrounds cells.  Water helps with homeostasis.  H 2 O – one hydrogen and two oxygen

 Made of carbon, hydrogen, oxygen – has LOTS of energy  Energy source for the cell and make up some cell parts (cell wall)  C 6 H 12 O 6 - sugar

 Energy rich organic compound – fats, oils and waxes  Cells store energy in them  Source of energy for the cell – make up the cell membrane

 Large organic molecules made up of C, H, O, Nitrogen, and sometimes Sulfur  Made up of smaller molecules called amino acids  Most of the structures in a cell are made of proteins – proteins called enzymes help chemical reactions in a cell take place

 Very long organic molecules made of carbon, oxygen, hydrogen, nitrogen, and phosphorus.  Contain the instructions that cells need to carry out the functions of life  DNA – genetic material that carries information and passed from parent to offspring.  RNA – helps in the formation of proteins