Intro and Chem

• Biology


  The study of living organisms
• What makes an organism alive

  • Shares six specific characteristics
• Six characteristics of life

  • Organized
  • Acquire materials and energy
  • Homeostatic
  • Respond to stimuli
  • Reproduce and grow
  • Evolutionary history
• Biological organization


  From an atom to the biosphere
• Acquiring materials and energy

  • Need to acquire food to perform work and build structures
  • Food provides energy through metabolism
  • Ultimate source of energy is the sun
  • Plants, bacteria, and algae can harvest sun's power through photosynthesis
• Homeostasis


  • Cells must operate under certain fairly constant conditions
  • Maintaining homeostasis prevents disease processes
• Responding to stimuli


  • Respond to both internal and external stimuli
  • Controlled by nervous and endocrine systems
• Reproduction and growth


  • Passing on genetic information to next generation
  • Genetic information in DNA and genes
  • Growth from single cell to trillions of cells
• Evolutionary history


  • Process by which a population of organisms change over time
  • Due to environment selecting the most fit (natural selection)
  • Example of white vs brown fur rabbits in Arctic
• Atoms


  The smallest unit of an element that retain the chemical and physical properties of the element
• Subatomic particles


  • Protons
  • Neutrons
  • Electrons
• Nucleus


  The central portion of the atom where protons and neutrons are located
• Electron orbitals/shells


  The areas surrounding the nucleus where electrons inhabit
• Positively charged protons


  Attract the negatively charged electrons
• Ion


  An atom that has had an electron removed or added, giving it a positive or negative charge
• Isotope


  An atom that has had a neutron removed or added, making it lighter or heavier, but without a charge
• Molecule


  Two or more like atoms combined chemically
• Compound


  Two or more different atoms combined chemically
• Chemical bonds


  Interactions between electrons of neighboring atoms that allow atoms to combine
• There are ninety two naturally occurring elements
• Matter can be a solid, gas, liquid, or plasma
• An element cannot be broken down by chemical means
• Examples of elements include carbon, hydrogen and oxygen
• If you add or remove a proton from an atom, you convert it to another type of atom
• We will explore covalent, ionic and hydrogen bonds next
• Covalent bonds


  The strongest type of bond, result from electrons being shared between two or more atoms
• Covalent bonds


  • Two electrons are being shared by the two atoms
  • Can also be built by four electrons being shared by two atoms (double covalent bond)
• Polar covalent bond


  Electrons are not shared equally between two atoms, one atom has a partially negative charge and the other has partially positive charges
• Polar covalent bond


  • Water (single oxygen atom and two hydrogen atoms)
• Ionic bonds


  Form when electrons are completely transferred from one atom to another, resulting in one positively charged atom and one negatively charged atom
• Ionic bond


  • Sodium and chloride ions (table salt)
• Ionic bonds


  • Positively charged atom (from nuclear proton)
  • Negatively charged atom (from extra electron)
  • Opposite charges are attracted
• Hydrogen bonds


  Weak chemical bonds between a hydrogen and another atom
• Hydrogen bonds


  • In water
• The insect in the image is able to walk on water by dispersing its weight over many hydrogen bonds
• Inorganic compounds


  Chemicals that do not contain carbon
• Important inorganic compounds in biology

  • Water
• Water


  • Most abundant inorganic compound
  • High heat capacity
  • High heat of evaporation
  • Solvent
  • Polar molecule
  • Cohesive
  • Adhesive
  • Solvent of life
• Solution


  Mixture of a solvent and its dissolved solute
• Hydrophilic


  Molecules attracted to the polar water molecule