Biology 1.2-1.4

4 elements that account for 96% human body

  • nitrogen
  • oxygen
  • carbon
  • hydrogen

Trace element that is essential for human health

  • Iron is an essential trace element
  • without iron human are tired, have food fortification
  • this can be helped by taking iron supplements and by having dietary diversification

Elements

  • can not be broken down
  • example: Oxygen, Hydrogen, Neon

Compounds

  • 2 or more different elements in a fixed ratio
  • example: H2O - water

Molecules

  • two or more atoms held together by covalent bonds
  • Example: H2 or O2

Covalent Bonds

  • do not transfer electrons but share them

Ionic Bonds

  • transfer atoms to another molecule

Polar Bonds

  • two atoms that differ in electronegativity

Non-Polar Bonds

  • electrons shared equally between two atoms that share electronegativity

Formation of Hydrogen Bonds

  • attraction between atoms carrying out opposite partial charges

Van Der Waal Interaction

  • weak interactions caused by atoms being close together
  • due to hot spots of weak charge that occur as electrons move around nucleus
  • weak interaction work together to stabilize bio-structure and interactions

Identify Relative Strength of Bonds in Bio-Systems

  1. covalent bonds
  2. ionic bonds
  3. hydrogen bonds
  4. Van Der Waal bonds

How are the shape and chemical properties directly related to its biological functions of ___?

  • the shape causes it to fit into the receptor on the brain allowing it to release pleasure
  • signals the brain cell to cause a reaction
  • structures function is to cause a reaction

Why is a water molecule polar ?

  • the Oxygen is more electronegative than Hydrogen
  • molecules are attached by polar covalent bonds
  • molecule is a wide V shape

What are the 8 properties of water

  • Cohesion
  • surface tension
  • adhesion
  • solvent properties
  • moderation of temperatures
  • evaporative cooling
  • expansion upon freezing
  • ionization and PH