CONCEPT 1. What is life?

• Characteristics of life: common set of elements, comprised of cells, genetic information, growth and change, respond to environment, use and make molecules, extract and use energy, exist in populations and evolve
• Cell theory. cells are the fundamental unit of life, all living organisms are comprised of cells, all cells come from pre-existing cells, modern cells have evolved from a common ancestor.
• A common origin of life is supported by the fact that the genetic code is universal, meaning that it is found in all living organisms in the same forms
• Life arose on Earth after the appearance of liquid water. A variety of molecules were able to be spontaneously formed within the liquid and eventually gave rise to nucleic acids, the building blocks of life.
• Properties of water. molecules may interact with each other through hydrogen bonding, high heat capacity, high melting point, high heat of vaporisation, cohesion, adhesion
• Cohesion. water molecules stick together
• Adhesion. the attraction of water molecules to other molecules
• Water is fundamentally connected to life as it facilitates the chemical reactions of life
• What are the elements of nature?

  Carbon, Hydrogen, Oxygen, Nitrogen
• Carbon is the primary component of all known life due to its ability to form stable covalent bonds with other atoms (up to four).
• Macromolecules: polymers containing thousand or more atoms. Includes carbohydrates, proteins, nucleic acids and lipids.
• What is a dipole-dipole force?

  A type of intermolecular force describing the attractive force between oppositely charged poles of two different molecules. Occurs between polar molecules and is also known as hydrophilic interaction.
• What are the requirements of polar molecules?

  Must have one or more polar bond where electrons are shared unevenly due to large difference in electronegativity between atoms and asymmetrical distribution of charge across the molecule.
• What is hydrogen bonding?

  Attraction between a hydrogen atom and an electronegative atom including oxygen, nitrogen and fluorine. Type of intermolecular force.
• Polarity of a water molecule.

  A) oxygen - partial negative

  B) hydrogen - partial positive

  
• What is dispersion force?

  A type of van de Vaals force where temporary dipoles formed when the electrons in a molecule end up on one side of a molecule results in the polarisation of another, creating an induced dipole.
• Where are dispersion forces found?

  In all molecules but most significant in non-polar molecules as it is the only intermolecular force they contain and in bigger molecules as the chance of temporary dipoles forming increases.
• What is an ion?

  an atom with an unequal amount of electrons and protons
• What is a dipole?

  a substance that has two charges, one positive side and one negative side.
• What is a polar molecule?

  A molecule with a positive and negative end.
• What is ion-ion interaction?

  Electrostatic interaction between opposite charges, occurring between a metal and non-metal.
• What is a covalent bond?

  A covalent bond is a type of chemical bond where two atoms share electrons. In a non-polar covalent bond, electrons are shared equally. In a polar covalent bond, electrons are shared unequally.