CHAPTER 14 - DNA (MOL S11) - Chapter 14 DNA The Molecule of...

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Chapter 14: DNA – The Molecule of Heredity 1 CHAPTER 14: DNA – THE MOLECULE OF HEREDITY 14.1 INTRODUCTION: How was the DNA double helix discovered? Deducing the double helix structure of DNA required insights from biology, physics, and chemistry. 14.2 NUCLEOTIDES – THE BUILDING BLOCKS OF DNA 14.2.1 Dexoyribose Sugar 14.2.2 Phosphate 14.2.3 Nucleic Acid Bases 14.2.4 Building a Complete Nucleotide 14.3 CONSTRUCTING THE DNA DOUBLE HELIX 14.3.1 Building a Polynucleotide Strand A polynucleotide is made by linking the phosphate of one nucleotide to the sugar of its neighbor. 14.3.2 Double-Stranded DNA A DNA molecule contains two anti-parallel nucleotide strands and hydrogen bonded base pairs. 14.4 DNA REPLICATION DNA replicates by using each strand as a template to synthesize a new complementary strand. Box 14.1: DNA Amplification using the Polymerase Chain Reaction (PCR) 14.5 PACKAGING DNA IN THE CELL DNA is compactly packaged in eukaryotic cells by winding around protein spools called histones. 14.6 CHAPTER SUMMARY
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Chapter 14: DNA – The Molecule of Heredity 2 14.1 INTRODUCTION: How was the DNA double helix discovered? We all know that we inherit certain traits from our parents, like the color of our hair and eyes. Scientists have also identified more than a thousand genetic disorders – such as sickle cell anemia and cystic fibrosis – that are also the result of heredity. Genetic tests now exist for many of these disorders, which raises challenging questions about how their results should be used. Many hospitals employ genetic counselors to provide parents with information about these potentially devastating problems for their children. The genetic traits that we inherit are determined by a molecule called DNA, which resides within the nucleus of our cells. One of the unifying themes of biology is that every living organism on Earth contains DNA. Figure 14.1 shows the DNA spilling out of an E.Coli bacterium. This large molecule stores the set of genetic instructions that determine almost all of the organism’s biological properties. What distinguishes bacteria from worms and humans is the specific type of information that is stored within the millions or billions of chemical building blocks that are used to construct DNA molecules. In this chapter we will apply the chemical principles we have learned to understand the molecular structure and biological function of DNA. Figure 14.1 Coiled up DNA bursts from a treated E.Coli bacterial cell (center). (Source: Ricki Lewis, Human Genetics) The DNA double helix has become a ubiquitous icon in our modern world. But within the timespan of scientific pursuits, its discovery occurred quite recently. It was just over fifty years ago, in February 1953, that James Watson and Francis Crick submitted a short paper to the prestigious journal Nature with a new proposal for the structure of DNA. They described the geometrical properties of the double helix, identified the rules by which the two DNA strands pair with each other, and suggested a mechanism for how DNA can replicate. A few days later, they posed proudly next to a molecular model of DNA that had provided crucial insights for their discovery (Figure 14.2).
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This note was uploaded on 11/05/2011 for the course MAP V55.0310.0 taught by Professor Tracejordan during the Spring '11 term at NYU.

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CHAPTER 14 - DNA (MOL S11) - Chapter 14 DNA The Molecule of...

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