U06_F08 - Unit 6 1 UNIT 6 PART A: DNA STRUCTURE PART B: DNA...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Unit 6 1 U NIT 6 P ART A: DNA S TRUCTURE P ART B: DNA R EPLICATION P ART A: DNA S TRUCTURE The most remarkable of all the properties of living cells and organisms is their ability to reproduce themselves with nearly perfect fidelity for countless generations. This continuity of inherited traits implies constancy, over thousands or millions, of years in the structure of the molecules that contain the genetic information. This hereditary information is preserved in DNA. DNA is a long thin organic polymer in which the linear sequence of covalently linked nucleotide subunits encodes the genetic message. Two of these polymeric strands are twisted about each other to form the DNA double helix, in which each monomeric subunit in one strand pairs specifically with the complementary subunit in the opposite strand. This unit provides an overview of the structure of nucleotides and nucleic acids found in most cells. Assignment: Nelson & Cox, pp. 271 - 281, 287 - 288, 945 - 971, 976. 1. Given the structures of the four common bases (Fig. 8-2, p. 272), identify each as a purine or pyrimidine and give its common name. (Note: You will not be asked to draw the structure of the bases, given the name.)
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Unit 6 2 2. Nucleosides and Nucleotides a. Given the structure of the bases in Fig. 8-2 (p. 272), draw structures representing (Fig. 8-1, p. 271): 1) a 2'-deoxynucleoside 2) a 2'-deoxynucleotide 3) a 2'-deoxynucleoside 5'-di- or triphosphate b. Use Fig. 8-1 (p. 271) to discuss the numbering convention for the pentose ring. Which atom in the sugar is the base attached to? What kind of bond joins the sugar to the base (p. 272)? Using Fig. 8-4 (p. 273), identify the atom that is found at the 2' position in deoxyribonucleotides? - in ribonucleotides? What functional group is at the 3' position in ribo- and deoxy-ribonucleotides? To which atom in the sugar is the phosphate bound? c. Use Fig. 8-4 (p. 273) to discuss the nucleotides found in DNA. Compare and contrast these nucleotides to those found in RNA. 3. Draw a section of DNA (use the letters A, C, G, and T to represent the structure of the base). Point out the following (Fig. 8-7, p. 275): a. phosphodiester bond (or linkage; note the difference between a phosphodiester bond and a phosphanhydride bond by comparing to Fig. 1-15, p. 12) b. sugar-phosphate backbone c. 5' and 3' ends d. overall charge 4. Distinguish between an oligonucleotide and a polynucleotide (p. 276). 5. Use Fig. 8-11 (p. 277) to discuss the hydrogen bonds that stabilize the DNA double helix.
Background image of page 2
Unit 6 3 6. How was DNA shown to be the genetic material (p. 278)? Why was the base composition (Chargaff's rules) important in suggesting a model for the structure of DNA (p. 278)? What other information was crucial in the
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/07/2009 for the course BIOBM 330 taught by Professor Blankenship during the Spring '09 term at Cornell University (Engineering School).

Page1 / 10

U06_F08 - Unit 6 1 UNIT 6 PART A: DNA STRUCTURE PART B: DNA...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online