BIOCHEMISTRY

DATE: Wednesday, October 21, 2015

TIME: 1:45 PM

WEATHER CONDITIONS: At the time of observation, it was approximately 74˚F outside. There was no precipitation during the time of observation. There was 30.25 in. of atmospheric pressure. The average humidity was 75%. There was very little wind throughout the day, and it was sunny all day.

CHANGES: There aren't many changes to report. The tree mostly has green leaves with a few dead, brown ones mixed in. There weren't any animals observed around the tree at the time of observation, except for several tiny bugs crawling up the trunk. There are a ton of dead leaves scattered around at the base of the trunk, and several acorns are sprinkled in.

AUTUMN FOLIAGE: Leaves change colors due to the four different pigments found inside them: chlorophylls, carotenoids, anthocyanins, and tannins. The amount of production of these pigments determines the leaf's overall color.

TRANSPIRATION:
Transpiration is the process by which water and moisture is carried throughout the plant, changing into vapor at some point and releasing back into the atmosphere. It's not really known for sure why plants, such as the Turkey Oak, perform transpiration, but it is thought to have something to do with temperature control. In order for any plant to grow and thrive, water must reach all parts of the plant, including far down into its roots. But also by spreading the water out among the plant, the plant maintains constant homeostasis.

CAPILLARY ACTION:
Cohesion describes a water molecule sticking together with another water molecule through hydrogen bonding, the type of bonding the exists between polar molecules. Capillary action is the process of water flowing from the roots of trees up to other parts of the tree, such up the trunk and to the leaves. This is a scientific phenomenon, because the water is flowing against gravitational forces. The cohesive forces occurring between the water molecules are what force the water to maintain the certain shape necessary for moving up the trunk of the tree. Adhesion is another property that is essential for this process to occur. This occurs between water and other polar molecules, and capillary action can only occur when adhesive forces are stronger than cohesive forces.

PROPERTIES OF WATER:
1. Ability to Moderate Temperature: Hydrogen bonding is very strong BETWEEN MOLECULES, and it takes a lot of energy to disrupt them. This allows the water molecule to resist temperature change, because not many molecules can break the bonds that exist between them. This property is important to Earth because it keeps Earth's bodies of water at a temperature that is suitable to all life forms that use them for their habitats.

2. Expansion upon Freezing: When water reaches a near-freezing temperature, the hydrogen bonds between the water molecules become stronger. The molecules are harder to break apart, and they form refined crystal-like structures that take up more space. Unlike when the water is at a warmer temperature, the water molecules are not moving around, so they remain clumped together, and the overall collection of water molecules expand. This property is crucial to life because ice sheets forming on the top of bodies of water contribute to the polar environments, and allow many organisms to live below the ice in the freezing water. It also prevents oceans from freezing completely solid.

3. Versatility as a Solvent: In aqueous solutions, ionic compounds and polar molecules can dissolve in water. Because many molecules are polar or charged, water readily dissolves with most molecules. Hydrogen bonding is what makes it possible for these bonds between water and the other molecule to exist. The positive hydrogen atom is able to bond with many other negative ions. This property is essential to life on earth because wherever water exists, it is bonding with other essential nutrients, chemicals, and minerals.

pH:
Acidic Solution: pH is less than 7; any substance that increases the H+ concentration of any solution to become a positive ion (a molecule with an overall positive charge).
Neutral Solution: pH is 7
Basic Solution: pH is greater than 7; any substance that reduces the H+ concentration of any solution to become a negatively charged ion.

ACID RAIN:
Acid rain is formed when compounds such as sulfur dioxide and nitrous oxide enter the atmosphere and create a chemical reaction. If these compounds rise high enough into the atmosphere, they mix with other elements such as oxygen and water to form acidic pollutants, or acid rain. The pollutants are carried far by the wind and then get mixed with the fog, sleet, and rain environments sometime experience. The acid rain, when it lands on the earth, will dissolve the essential nutrients and minerals that plants and animals need in order to grow and thrive. Acid rain also causes aluminum, which is a toxic element to the plants and animals, to release into the soil.

REFERENCES:

• http://harvardforest.fas.harvard.edu/leaves/pigment
• http://water.usgs.gov/edu/watercycletranspiration.html
• http://www3.epa.gov/acidrain/education/site_students/whatcauses.html
• http://chemwiki.ucdavis.edu/Physical_Chemistry/Physical_Properties_of_Matter/Bulk_Properties/Cohesive_And_Adhesive_Forces/Capillary_Action
• http://socratic.org/questions/how-do-water-hydrogen-bonds-moderate-temperature
• Water and pH lecture on class page
• https://en.wikibooks.org/wiki/Structural_Biochemistry/Unique_Properties/Expansion_upon_Freezing
• http://water.usgs.gov/edu/qa-solvent.html