Chapter 8

Chapter 8 - d The two strands are joined together by...

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1) DNA structure and function a) DNA is the blueprint for how an organism is made b) Carries all the information on how to build the organism and how to operate all of its processes = genetic information c) Genetic information is passed down from generation to generation in the form of DNA 2) Overall organization a) DNA molecules are packaged into units called chromosomes b) Small segments of DNA that contain the instructions for particular characteristics are called genes c) DNA consists of two strands of nucleotides joined together in the middle by hydrogen bonds. This double stranded molecule is twisted into a double-helix shape 3) Nucleotides are the basic, repeating unit of DNA a) Consist of a 5 Carbon sugar, a phosphate group, and a base i) Adenine=A ii) Thymine=T iii) Guanine=G iv) Cytosine=C 4) DNA is double stranded a) Nucleotides are strung together to form each strand b) Each “link” of the strand is held together by covalent bonds between the sugar of one nucleotide and the phosphate group of the next c) This structure of linkage is called the “sugar-phosphate backbone” of DNA
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Unformatted text preview: d) The two strands are joined together by hydrogen bonds that form between the bases 5) Hydrogen bonds form between specific bases a) A pairs with T b) G pairs with C c) The bonds in the sugar-phosphate backbone and between the bases cause the molecule to be twisted into a double helix 6) DNA replication a) Copying DNA i) DNA must be copied before a cell divides, so that the two new cells contain complete sets of the DNA (complete sets of the chromosomes) ii) If a cell doesn’t contain a complete set of chromosomes, it cannot function properly b) The structure of DNA dictates a specific method of replication i) Complementary nucleotides are nucleotides that pair specifically with one another ii) The two DNA strands in a double helix are therefore complementary strands iii) The complementary strands are oriented in opposite directions c) Diagram of replication March 13, 2008 1. Drawing in notebook 2....
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