Notes explaining the structure of DNA, replication process of DNA, how mutations work in DNA, and the Polymerase chain reaction process

Essay by skierdude1000College, Undergraduate February 2005

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-DNA is a polymer of nucleotides

-Each nucleotide consists of a nitrogenous base, a sugar, and a phosphate group

-The sugar in DNA is a pentose sugar called deoxyribose

-The different kinds of bases are adenine, thymine, guanine, and cytosine

-In DNA, there is a 1:1 ratio of nucleotide bases: number of adenine = number of thymine and number of guanine = number of cytosine

-DNA consists of 2 strands in a shape called a double helix

-Double helix is 2-nm in diameter

-The strands have a sugar-phosphate backbone

-The two strands are held together by hydrogen bonds

-The rungs of the helix consist of purine/pyrimidine rings

-Adenine and guanine are purines

-Purines have two organic rings

-Cytosine and thymine are pyrimidines

-Pyrimidines have a single organic ring

-Pyrimidines pair with purines to form rungs of helix (adenine with thymine and guanine with cytosine)

-Adenine and Thymine form 2 hydrogen bonds

-Guanine and Cytosine form 3 hydrogen bonds

-The helix makes one full turn ever 3.4

nm along its length

-Bases are stacked .34 nm apart

-Ten layers of base pairs in each turn of the helix

-Replication is explained by the Semiconservative model

-When a double helix replicates, each of the two daughter molecules will have one old strand derived from the parent molecule and one newly made strand

-DNA replication involves unzipping the DNA molecule into 2 strands

-Each strand acts as a template to assemble a new, complementary strand

-Results in two identical double-stranded molecules of DNA

-How DNA replication occurs

-Helicase unwinds the DNA forming a replication fork (Y-shaped region where the new strands of DNA are elongating)

-Single-stranded DNA binding proteins prevent single strand of DNA from recombining

-RNA Primase initiates DNA replication at special nucleotide sequences called origins of replication. RNA Primase uses short...