CHEM114A_Midterm 1_Key

CHEM114A_Midterm 1_Key - Name _ Midterm Exam 1 Chem114A...

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Name _______________________________ 1 Midterm Exam 1 Chem114A (Instructor: Hector Viadiu) Fall 2009 (October 16, 2009) 1. Explain the origin of eukaryotic cells (5 points). inefficient anaerobic ancestral eukaryote engulfed an aerobic bacterium (efficient metabolism). -Some bacterial genes moved to nucleus; the new symbiotic system (endosymbionts become mitocondria) can carry out aerobic catabolism. (nonphotosynthetic eukaryote) -Cyanobacteria endosymbiosis results in photosynthetic eukaryotes 2. Explain the experiment that was carried out by Urey and Miller that helps us to understand the origin of organic compounds? (5 points). -experimental input: NH3, CH4, H2, H20 @ 80C, electrodes providing energy (sparks) -experimental output: Resulted in CO and CO2 in gas phase and some amino acids, hydroxy acids, aldehydes and HCN in aqueous phase. -experiment proved Oparin’s theory of primitive reducing atmosphere. 3. Explain how the cell manages to carry out endergonic reactions (5 points). Endergonic reactions are carried out in cells by coupling to highly exergonic reactions (ATP->ADP) 4. Briefly explain the 4 non-covalent forces that are important to understand macromolecules. Which one is the strongest? (5 points). strongest: Ionic interactions H-bonding Hydrophobic interactions Van der Waals interactions/induced dipoles 5. Mention 5 properties of water that make it a unique solvent (5 points). -high heat capacity -high melting and freezing points -available solid, liquid, and gas on earth -cohesive, polar, high surface tension and can H-bond with itself (forming networks) and polar compounds -dissolves many polar solutes -pH ~ 7 -Osmotic pressure can move large volumes of water across membranes 6. Draw the three ionization states of glycine (3 points). Which one is the zwitterionic state and why? (2 points).
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Name _______________________________ 2 H 3 N OH O H 3 N O O H 2 N O O zwitterionic need correct structure and ionization states to get full credit. It's Zwitterionic because it has negative and positive charges on the same molecule. 7. Draw and name 5 aliphatic amino acids (5 points).
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This note was uploaded on 05/26/2010 for the course CHEM chem 114A taught by Professor Gourisankarghosh during the Fall '06 term at UCSD.

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CHEM114A_Midterm 1_Key - Name _ Midterm Exam 1 Chem114A...

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