Chemistry

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Chemistry
You gotta’ know it to understand
LIFE!
Atomic Structure
Elements
Table 2-1
Isotopes
• Some applications of radioactive isotopes in
biological research are:
– Dating fossils
– Tracing atoms through metabolic processes
– Diagnosing medical disorders
Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings
Positron Emission Tomography
•
http://www.sumanasinc.com/webcontent/animations/content/positronemissiontomography.html
Ions
• Normal Atoms
Ions
Electron Energy Levels
Electron Energy Levels
• Why “Octet”
Ionic Bonding
Covalent Bonding
Molecules
Hydrogen
Molecules
Amino Acids
Insulin
Lipid
Enzyme
Molecule
DNA
Chemical Reactions
Synthesis vs. Decomposition
Two important Biological Reactions
1. SYNTHESIS
eg.
2. DECOMPOSITION
eg.
WATER
Hydrogen Bonding- Hydrogen will
often have a positive (+) charge when
bonded to another element in a molecule.
This positive charge can interact with other
charges on elements of other molecules or
even within the same molecule
H Bonding affects boiling and freezing points
of compounds as well as the shapes of
many biological molecules.
WATER
Water is a polar compound
Four emergent properties of water
contribute to Earth’s fitness for life
• Four of water’s properties that facilitate an
environment for life are:
– Cohesive behavior (capilary action)
– High Specific Heat (Ability to moderate
temperature)
– Expansion upon freezing (Lowers its Density)
– Solvent properties
ALL OF THESE ARE THE RESULT OF
WATER’S POLAR PROPERTY
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 3-UN4
Ice: stable hydro- Liquid water:
gen bonds
transient hydrogen
bonds
Water’s Cohesive Property
The specific heat is the amount of heat required to raise the
temperature by one degree Celsius.
Specific Heat Capacity of water is Higher than most substances
.
and is the result of water’s polar property
CAUTION!
FILLING
IS HOT?
Specific heat capacity of water is larger than
soil, so the rise of temperature is less for
water, all
other things being equal.
This is why it’s typically cooler
near the coast in summer and
warmer in the winter.
Fig. 3-5
Los Angeles
(Airport) 75°
70s (°F)
80s
San Bernardino
100°
Riverside 96°
Santa Ana
Palm Springs
84°
106°
Burbank
90°
Santa Barbara 73°
Pacific Ocean
90s
100s
San Diego 72°
40 miles
Adhesion
• Adhesion is the property of water that
allows it to cling to other substances.
Water’s polar characteristics cause it to be attracted to
other polar substances OR it can induce a charge on
the substance to which it clings.
This adhesion causes a phenomenon
known as Capillary Action
Water Transport in Plants
This transport is a property
of water’s POLARITY that
give it both
cohesiveness and
adhesiveness
Acids and Bases
Threats to Water Quality on Earth
• Acid precipitation refers to rain, snow, or
fog with a pH lower than 5.6
• Acid precipitation is caused mainly by the
mixing of different pollutants with water in
the air and can fall at some distance from
the source of pollutants
• Acid precipitation can damage life in lakes
and streams
• Effects of acid precipitation on soil chemistry
are contributing to the decline of some
forests
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
• Human activities such as burning fossil fuels
threaten water quality
• CO2 is released by fossil fuel combustion
and contributes to:
– A warming of earth called the “greenhouse”
effect
– Acidification of the oceans; this leads to a
decrease in the ability of corals to form calcified
reefs
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 3-11
EXPERIMENT
RESULTS
40
20
0
150
250
200
[CO32–] (µmol/kg)
300
•
http://ww
w.youtub
e.com/wa
tch?v=fJb
yC-eqrfs
You should now be able to:
1. List and explain the four properties of water
that emerge as a result of its ability to form
hydrogen bonds
2. Distinguish between the following sets of
terms: hydrophobic and hydrophilic
substances; a solute, a solvent, and a
solution
3. Define acid, base, and pH
4. Explain how buffers work
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
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