| REVIEW GUIDE: DNA structure and replication
Key Ideas: � DNA is the nucleic acid that stores and transmits the genetic information from one generation of an organism to the next. � DNA is made up of units of nucleotides. Each nucleotide is a molecule made up of three parts: a 5-carbon sugar called deoxyribose, a phosphate group, and a nitrogen base. � DNA has four nitrogen bases: adenine, thymine, cytosine, and guanine. Adenine belong to a group of compounds called purines and thymine and cytosine belong to a group of compounds called pyrimidines. � During replication, the DNA molecule unzips, or separates, into two strands. Each of the separated strands serves as a template, or pattern, for the attachment of complementary nucleotides. � Restriction enzymes are enzymes that cut DNA molecules at specific nucleotides sequences. � In gel electrophoresis, an electrical current is used to separate a mixture of DNA fragments from each other. Key Words: Genetic code DNA nucleotide adenine Guanine cytosine thymine base pairing Hydrogen bonds replication complimentary bases Okazaki fragments Deoxyribose Restriction enzymes gel electrophoresis purines pyrimidines A little practice� Here is a DNA sequence 5� ATGGTAATC 3� Draw the molecule using a circle for the phosphate group, pentagon for the sugar, and rectangle for the nitrogen bases. Draw the molecule so that the 5� end is on the top. Next draw the same DNA sequence undergoing DNA replication. Which side is continuous, which side is discontinuous? |