Biochemistry 1: Water

1. Biochemistry 1:
Water
ppt. by Robin D. Seamon
Amoeba Sisters: Properties of water (7 min)

2. 1. Amoeba Sisters: Properties of water (7 min)
2. POGIL: Properties of Water
3. Lecture
4. WS

3. IMPORTANCE OF WATER
Without water, most of our bodily processes
would not work.
About 60% of our bodies are made up of water.
• 90% blood (plasma) is water
• Carries wastes out of the body (sweat, tears,
urine)
• Helps maintain body temperature homeostasis
(sweat)
Water is used in many of the biochemical
reactions within our cells.

4. H2O
CHEMISTRY REVIEW:
• Oxygen is in group 16,
therefore it has 6 valence
(outer) electrons.
• Hydrogen is in group 1 so
has 1 valence electron.
• (The STABLE number state
is to have 8 electrons in the
valence shell.)
• How many more does
oxygen need to be stable?
• 2 Hydrogen molecules
provide that: creating a very
strong, stable bond.
2 Hydrogen atoms
1 oxygen atom
Covalent bond:
sharing electrons

5. Polarity of water
Water is considered to be a polar substance
because one side of the molecule has a POSITVE
charge and one of side has a NEGATIVE charge.

6. Positive and negative particles attract one another:
Hydrogen bonds- bonds
of water pulling
together; not as strong
as other bonds

7. S T I C K I N G T O G E T H E R :
• Cohesion- force that holds molecules of a
material together
• Adhesion- force that holds different substances
together
Water drop and
water drop
Water drop and
paper
7

8. The cohesion of water creates surface tension.
• This bond is strong enough to hold small
insects.
• It is also how a water-needle compass works-
the needle floats on the surface tension as it
orients itself towards the Earth’s magnetic
North Pole.

9. D I S S O L V I N G
• Water is a solvent- it dissolves solutes of solids,
liquids & gases
• Solute- substance that dissolves
• Solution- mixture of solvent and solute
(EXAMPLES: blood, sweat, tears)
http://www.chem4kids.com/files/matter_
solution.html
9

10. W A T E R
• universal solvent- most substances will dissolve
in it
WHY?
• Polar- have two areas that have opposite
charges
10

11. 11
+ ions pull toward
negative side of water
molecule
Water surrounds charged particles and
pulls them apart
- ions pull toward
positive side of water
molecule
http://www.chemistryland.com/CHM107/Water/WaterTutorial.htm#
VIDEO: How polarity makes water behave strangely (4min)

12. 12
pH- power of Hydrogen
• The acid/base balance
• 7 is neutral
VIDEO: Strengths & Weaknesses of acids & bases (3:50)
VIDEO: Crash Course Chemistry#30 pH & pOH (11min)
 STRONGER baseSTRONGER acid 

13. Acids release hydrogen ions (H+) in water.
HCL  H+ + Cl-
Bases release hydroxide ions (OH-) in water.
NaOH  Na+ + OH-
Sodium
Hydroxide
Hydrogen
Chloride
Sodium
Chloride = salt
Neutral
solutions- have
same number of
H+ ions and OH-
ions.

14. 14
NEUTRAL
Solubility of heavy
metals
Algal blooms
More Hydrogen Less Hydrogen
HIGHER
TEMP.
pH

15. Buffer-
• Chemical substance that
neutralizes small amounts of
acids and bases
• Help maintain pH homeostasis
• Blood- good buffer
CC VIDEO #2 Water (10 min)