DNA Structure and Replication

• • Deoxyribose acid (DNA) is a polymer made up of many repeating monomeric units called nucleotides
  • A molecule of DNA consists of two polynucleotide strands which run in opposite directions (antiparallel)
  • The two antiparallel strands are joined together by hydrogen bonds between nitrogenous bases
• Base pairing in DNA:

  
• What is the procedure for extracting DNA?

  1. Grind the sample in a mortar and pestle (breaks down the cell wall)
  2. Mix the sample with detergent (breaks down the cell membrane releasing the contents into the solution)
  3. Add salt (breaks down proteins [hystones] associated with the DNA in the nuclei)
  4. Add a layer of ethanol on top of the sample (causes the DNA to precipitate out of the solution)
  5. The DNA will be seen as white strands forming between the layer sample and the layer of alcohol. The DNA can be picked up by spooling it onto a glass rod
• What is the process of DNA replication?

  DNA Replication occurs through the semi-conservative mechanism, where each strand of the DNA double helix acts as a template for the synthesis of a new complementary strand. The DNA strands separate, and each strand is used as a template to build a new complementary strand by the addition of nucleotides.
• What is the process of Semiconservative replication?