2012 Summer Assignment Notes- Ap Biology

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Summer Assignment – AP Biology – Chapters 2-5
Chapter 2
1. CHNOPS are the six most crucial elements in most macromolecules. Name them. Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorous, Sulfur.

2. Create a chart and state how many bonds each of the CHNOPS elements can form. Carbon| Hydrogen| Nitrogen| Oxygen| Phosphorous| Sulfur| 4| 1| 3| 2| 3 or 5| 2|

3. Create a Venn Diagram to compare and contrast polar covalent bonds, nonpolar covalent bonds, and ionic bonds.

4. Why is water a polar molecule? Draw a water molecule and show the δ+ and δ- poles. Water is a polar molecule because electrons in a water molecule are not shared equally, and electrons are more strongly attracted to and spend more time orbiting around oxygen atoms because oxygen has a bigger electronegativity differencce than hydrogen. Therefore, oxygen molecules have a slight negative charge, and hydrogen molecules have a slight positive charge.

5. How are hydrogen (H) bonds and Van der Waals interactions similar and different?

6. What is the most common molecule to find H bonds? Water.

7. Draw one central water molecule, and show how this can H bond with four additional water molecules.

8. Write out the equations for photosynthesis. Indicate the products and reactancts. 6CO2 + 6H20 (reactants) C6H12O6 + 6O2 (products)

Chapter 3
1. Why would you not see two water molecules arranged as shown below?

Since the hydrogen molecules are slightly positive and the oxygen molecules are slightly negative, they are attracted to each other. Two negatively charged oxygen molecules are not attracted to each other because they both have the same charge and will repel each other.

2. What are the four major properties of water? Cohesive/ adhesive behavior, ability to moderate temperature (high specific heat and evaporative cooling, expansion upon freezing (density), and universal solventa ability.

3. What is the difference between cohesion and adhesion? On what structural property of water are both dependent? Cohesion is the binding together of like molecules, often by hydrogen bonds (co= together or “to share”). Adhesion is the attraction between different kinds of molecules. (think “adhesive” like tape or glue= bonds to a completely different thing). They are both dependent on hydrogen bonding formed between between two different water molecules.

4. Why is surface tension associated with cohesion and not adhesion? At the surface of the water, there is an ordered arrangement of water molecules that are hydrogen-bonded to each other and to the water BELOW, not the air above the water. This has a result of pulling the water molecules “down” away from the air-water interface.

5. Use the properties cohesion, adhesion, high specific heat, evaporative cooling, expansion upon freezing, and universal solvent ability to create a chart that has the following information: property of water, effects of this property, and how this can be seen in nature.

6. Something that is hydrophobic will not dissolve in water. Explain why it does not and give an example of a hydrophobic substance. Hydropobic substances will not dissolve/ dissocaite in water because they are nonionic, nonpolar, or cannot form hydrogen bonds for some other reason. A hydrophobic substance’s behavior results the wide-spreadness of relatively nonpolar bonds, which don’t bond well with water, a polar molecule and a hydrphilic substance. Nonpolar covalent bonds are all sharing electrons equally, so there are no positive or negative poles to create attraction. Some examples of hydrophobic substances include: oil, butter, tar, gasoline, and anything else oily or oil based.

7. The phrase “like dissolves like” is often used in biology and chemistry. In terms of being hydrophilic and hydrophobic, what does this mean? Hydrophilic substances will only dissolve other hydrophilic substances, and hydrophobic substances...
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