Life Occurs in Water

1
Life Occurs in Water

• The All Purpose Molecule

2
The All Purpose Molecule

• Of all the molecules of life none is so
  omnipresent as water.
• Our cells are 70 water.

3
Primordial Soup

• Life began in water.
• When our ancestors arose from the sea to become
  land dwellers we brought water along with us
  within our cells

4
The All Purpose Molecule

• Water participates in all kinds of chemical
  reactions.
• Bounded by water insoluble membranes cells owe
  their shape and rigidity to water.
• Water provides and inexhaustible supply of the
  HYRDOGEN ions needed for converting the suns
  energy into chemical energy.

5
(No Transcript)
6
The All Purpose Molecule

• The key to the importance of water is its
  polarity.
• Composed of a single OXYGEN atom sharing
  electrons with two HYDROGEN atoms like a head
  wearing a pair of Mickey Mouse ears a water
  molecule looks quite ordinary.
• While the molecules overall electric charge is
  neutral, the oxygen tends to pull negatively
  charged particles towards it leaving the HYDROGEN
  ears slightly positive charged relative to the
  more negative OXYGEN head.

7
Properties of Water

• 1. Becomes less dense as it freezes

8
Properties of Water

• 2. Evaporative cooling

9
Properties of Water

• 3. Conducts electricity

10
Properties of Water

• 4. Its high specific heat

11
Properties of Water

• 5. Its activity as an almost universal solvent

12
Properties of Water

• 6. Its high surface tension cohesiveness and
  Adhesiveness

13
Questions to Ponder

• Oxygen is more electromagnetic than Hydrogen.
  What does this mean in regards to the covalent
  bond that holds a water molecule together?
• A water molecule is a polar molecule, what is
  that?
• What type of bond holds water molecule(s)
  together?

14
Questions to Ponder

• What causes the extraordinary qualities found in
  water?
• What is cohesion? Why does it happen?
• What is transpiration and what affect does
  cohesion have on the water in a plant during
  transpiration?

15
Questions to Ponder

• Show and explain surface tension. How does
  hydrogen bonding allow for such a feat?
• What is
• Kinetic energy
• Heat
• Temperature
• Calorie
• Joule

16
Questions to Ponder

• Water acts as a heat bank? What?
• What is specific heat? Compare the specific heat
  of water to sand, and air.
• The pacific NW was very mild winters. Why does
  the specific heat of water allow for this?

17
Questions to Ponder

• Heat of vaporization, evaporative cooling,
  sweating, and high humidity.
• Explain the exotic nature of water as a solid.
• Solution, solvent, solute.

18
Questions to Ponder

• Hydrogen shell, show and explain this property of
  aqueous solutions?
• FINALLY, the pH scale (acid, base, buffer, H
  OH-).