Chemical Compounds in Cells

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					Chemical Compounds in
            Section 3, Chapter 1
              Cells and Heredity
Elements and Compounds
 An element is any substance that cannot be
  broken down into simpler substances.
 Ex: Oxygen
 The smallest unit of an element is an atom.
 The elements found in living things include
  carbon, hydrogen, oxygen, nitrogen,
  phosphorus, and sulfur.
 When two or more elements combine
  chemically, they form a compound.
 Ex: Carbon Dioxide
 The smallest unit of many compounds is
  called a molecule.
 Most elements in living things occur in the
  form of compounds.
Organic and Inorganic
 Some important groups of organic
  compounds found in living things are
  carbohydrates, lipids, proteins, and nucleic
 Most compounds that contain carbon are
  called organic compounds.
 A carbohydrate is an energy-rich organic
  compound made of the elements carbon,
  hydrogen and oxygen.
 Sugars and starches are examples of
 Carbs are important components of some cell
  parts. Ex: the cellulous found in the cell walls
  of plants is a type of carbohydrate.
 Lipids are energy-rich organic compounds
  made of carbon, hydrogen, and oxygen.
 They contain even more energy than
 Cells store energy in lipids for later use.
 EX: during winter, a dormant bear lives on
  energy stored in fat within its cells.
 Proteins are large organic molecules made of
  carbon, hydrogen, oxygen, nitrogen and in
  some cases, sulfur. A bird’s feather, a
  spider’s web, and your fingernails are mainly
  made of proteins.
 Protein molecules are made up of smaller
  molecules called amino acids. Although there
  are only 20 common amino acids, cells can
  combine them in different ways to form
  thousands of different proteins.
Functions of Proteins
 Much of the structure of cells is made up of
 The proteins known as enzymes perform an
  important function in the chemical reaction
  that takes place in the cells.
 An enzyme is a type of protein that speeds up
  a chemical reaction in a living thing.
 EX: enzymes in your saliva speed up the
  digestion of food by breaking down starches
  into sugars in your mouth.
Nucleic Acids
 Nucleic acids are very long organic molecules
  made of carbon, oxygen, hydrogen, nitrogen
  and phosphorus.
 There are two kinds of nucleic acids:
  Deoxyribonucleic Acid (DNA) and Ribonucleic
  Acid (RNA)
 DNA – is the genetic material that carries
  information about an organism and is passed
  from parent to offspring.
 RNA – plays an important role in the
  production of proteins.
Water and Living Things
 Most chemical reactions within cells could not
  take place without water.
 Water also helps cells keep their size and
 Because water changes temperature slowly, it
  helps keep the temperature of cells from
  changing rapidly.

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