642-2010-01 - Chem-642 Instructor Junghuei Chen 105 Drake...

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Unformatted text preview: Chem-642 Instructor: Junghuei Chen, 105 Drake, 831-1035, [email protected] Office Hours: Wednesdays, 9:30-11:30 AM Down Load Power Points: http://www.udel.edu/chem/course/courseS2010.html Grading: First exam (30%), Second Exam (30%), Final examination (40%). Date to Remember: First Exam: March 11 March 30, April 1 (Spring recess; no class) Second Exam: April 22 Last day of class: May 18 Final exams week: May 19-26 DNA, Chromosomes, and Genomes The nucleosome An egg cell. The DNA of this single cell contains the genetic information needed to specify construction of an entire multi- cellular animal. All cells store their genetic information in DNA Figure 11 The hereditary information in the egg cell determines the nature of the whole multicellular organism. (A and B) A sea urchin egg gives rise to a sea urchin. (C and D) A mouse egg gives rise to a mouse. (E and F) An egg of the seaweed Fucus gives rise to a Fucus seaweed. Chromosomes in cells. (A) Two adjacent plant cells photographed through a light microscope. The DNA has been stained with a fluorescent dye (DAPI) that binds to it. The DNA is present in chromosomes, which become visible as distinct structures in the light microscope only when they become compact structures in preparation for cell division, as shown on the left. The cell on the right, which is not dividing, contains identical chromosomes, but they cannot be clearly distinguished in the light microscope at this phase in the cells life cycle, because they are in a more extended conformation. (B) Schematic diagram of the outlines of the two cells along with their chromosomes. Hereditary information is carried on Chromosomes that consist of both DNA and proteins Experimental demonstration that DNA is the genetic material. (Avery) These experiments, carried out in the 1940s, showed that adding purified DNA to a bacterium changed its properties and that this change was faithfully passed on to subsequent generations. Two closely related strains of the bacterium Streptococcus pneumoniae differ from each other in both their appearance under the microscope and their pathogenicity. One strain appears smooth (S) and causes death when injected into mice, and the other appears rough (R) and is non-lethal. (A) This experiment shows that a substance present in the S strain can change (or transform) the R strain into the S strain and that this change is inherited by subsequent generations of bacteria. (B) This experiment, in which the R strain has been incubated with various classes of biological molecules obtained from the S strain, identifies the substance as DNA. The structure and function of DNA A DNA Molecule Consists of Two Complementary Chains of Nucleotides DNA and its building blocks....
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This note was uploaded on 05/24/2010 for the course BIOCHEM chem642 taught by Professor Chen during the Spring '10 term at University of Delaware.

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642-2010-01 - Chem-642 Instructor Junghuei Chen 105 Drake...

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