Notes: Although there is a minimum word count of 2500 words for the entire exam (about 625 words or more per question), you will find that it is likely going to require more than the minimum to fully answer the questions. You may not copy or quote from any source. All information must be re-written in your own words.

Question 1: Elements and Molecules

.Describe the origin of elements heavier than hydrogen, the structure of atomic nuclei and their electron orbitals, and chemical bonding. Include in your answer:

a. a description of the origin of stars, nuclear fusion, and supernova events

b. a general discussion of the shapes of electron orbitals of hydrogen and carbon and the nature of covalent, polar covalent and ionic boding

c. the role of functional groups in defining biomolecules with carbon skeletons and how chemical bonds and functional groups define the shapes of large biomolecules

Question 2: Water.

Describe water’s structure and properties that make it unique among small molecules and essential for life. Include in your answer

: a. a description of the structure of the water molecule including atoms, bond angles, polarity, hydrogen bonding, and interactions with other molecules and why water is a liquid while molecules of greater sizes are gases

b. how molecules are either hydrophobic or hydrophilic and the importance of electronegativity and the nature of chemical bonds

c a description of the pH scale, the pH of water at different temperatures, and the reason partner exchange is important to life’s chemistry

d. a description of water’s high heat capacity and how it serves as a “heat buffer” moderating increases and decreases of temperature in cells and in lakes and oceans.

Question 3: Light and Color.

Describe (1) the nature of light as wave and particle and how it is absorbed and emitted by matter, (2) the production of pigmentary color by differential absorption and production of structural colors by reflection, diffraction and refraction, and (3) the function of color and color change in animals. Include in your answer:

a. a description of the common features of pigment molecules that result in color

b. a description of how light waves can cancel and be additive and how these properties are used in the coloration of the Iridescent Phyllodoce (Phyllodoce multipapillata) and how scattering can produce the blue of the Western Bluebird (Sialia mexicana) and a description of how sunlight and the atmosphere create a blue sky.

c. a description of the nature of color and color change in the Opalescent Squid (Loligo opalescens) and, in particular, the process by which iridocytes can “tune in” a particular color to match ambient light.

Question 4: Why Earth?

Describe the development of Earth as a planet in our solar system and how this history has led to a planet that supports life? Include in your answer:

a. a description of the origin of planetary systems and a comparison of the features of Venus, Earth and Mars

b. a description of the events creating the Hadean Earth and its structure from its core to the surface

c. a description of how prebiotic organic molecules were produced, how early molecules may have been polymerized, and how the first “cells” that isolated and concentrated biomolecules from the open waters of early Earth were formed

References Immediately following the essay, two lines below the last line of your last answer (do not skip to a following page), list all sources used in writing your essay to answer the question. Do not use in-text citations and do not use footnotes. Simply list your sources in this “References” section. You must have a References section with at least five references which you have used in preparing your answers