chemistry you gotta’ know it to understand life!
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ChemistryYou 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 InsulinLipid
DNA
Enzyme Molecule
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 Four emergent properties of water contribute to Earthwater contribute to Earth’’s s fitness for lifefitness for life
• Four of waterFour of water’’s properties that facilitate s properties that facilitate an environment for life are:an environment for life are:
– Cohesive behavior (capilary action)Cohesive behavior (capilary action)– High Specific Heat (Ability to moderate High Specific Heat (Ability to moderate
temperature)temperature)– Expansion upon freezing (Lowers its Expansion upon freezing (Lowers its
Density)Density)– Solvent propertiesSolvent properties
ALL OF THESE ARE THE RESULT OF ALL OF THESE ARE THE RESULT OF WATER’S POLAR PROPERTYWATER’S POLAR PROPERTYCopyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 3-UN4
Liquid water:transient hydrogenbonds
Ice: stable hydro-gen 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
San Diego 72°
40 miles
Pacific Ocean
70s (°F)
80s
90s
100s
Santa Barbara 73°
Los Angeles (Airport) 75°
Burbank90°
San Bernardino100°
Riverside 96°Santa Ana 84° Palm Springs
106°
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
Cal
cif
icat
ion
rat
e(m
mo
l C
aCO
3
per
m2 p
er d
ay)
[CO32–] (µmol/kg)
150 200 250 3000
20
40
• http://www.youtube.com/watch?v=fJbyC-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 pH4. Explain how buffers work
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
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