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Unformatted text preview: Department of Chemical Engineering ChE 170 University of California, Santa Barbara Fall 2010 Problem Set No. 1 Due: Thursday, 10/07/10 at the start of class Objective : To understand the components and basic structure of cells, and to develop a picture of the molecular-scale interactions relevant to biological processes. Review problems You should pay special attention to these questions after reading. Note that the answers are given in the back of the book. Formulate your answers fully first and then check them. This can be a significant aid in your understanding of the material, and similar questions may be asked on the final. You do not need to provide written answers in the solutions you hand in. • ECB 1-9 • ECB 1-11 • ECB 1-16 • ECB 2-17 • ECB 2-19 • ECB 3-11 Problem 1 Draw the chemical structure of a small fragment of DNA, a dinucleotide of thymine and guanine, whose sequence is abbreviated TG. Be sure to show all double bonds and formal charges. Be sure your sequence is not reversed. Problem 2 Consider that the human genome (i.e., the total DNA content containing genetic information) consists of roughly 3 billion nucleotide pairs. When two unrelated human individuals are compared, roughly 0.1% of these nucleotides varies. The variable part of the DNA sequence gives rise to genetic diversity, while the remaining common 99.9% is what makes each individual distinctly human. Consider a random individual to whom you are not related. What is the probability that your genome is identical to theirs? Express your answer as 1 in 10 x . Recall that four bases are possible at each nucleotide in a DNA sequence. Problem 3 In the largely aqueous environment of the cell, complementary DNA strands spontaneously self-assemble to form the iconic so-called “B” helical structure that is so familiar in popular science. At first glance, this may seem counterintuitive because the phosphate-deoxyribose backbone contains negative charges that would result in repulsive like-charge interactions between the two strands. (a) The human genome consists of roughly 3 billion base-paired nucleotides. In eukaryotes, DNA exists inside of the cell nucleus, and a typical mammalian nucleus is spherical with a diameter of about 6 microns. What typical total concentration of positively-charged, monovalent species (e.g., Na+ or K+) must be present inside the nuclei of human cells in order to maintain an overall charge-neutral environment there? Express your answer in millimolar. Compare it to the value of ~150 mM often found in the cytosol....
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This note was uploaded on 12/29/2011 for the course CHE 170 taught by Professor Ceweb during the Fall '10 term at UCSB.
- Fall '10
- Chemical Engineering