DNA and RNA

• What are DNA and RNA classified as?

  Types of nucleic acids
• What is the primary function of DNA?

  To store genetic information
• What is one of the main roles of RNA?

  To transfer genetic information to ribosomes
• What is a nucleotide made from?

  A sugar, a base, and a phosphate group
• What is the sugar in DNA called?

  Deoxyribose
• What are the four possible bases in DNA?

  Adenine, thymine, cytosine, guanine
• What sugar does RNA contain?

  Ribose
• What base replaces thymine in RNA?

  Uracil
• What is the structure of DNA?

  Two polynucleotide chains in a double helix
• What is the role of DNA helicase in replication?

  To break hydrogen bonds between bases
• What does semi-conservative replication mean?

  Half of the original DNA is retained
• How do new strands form during DNA replication?

  By complementary base pairing with templates
• What enzyme catalyzes the joining of nucleotides?

  DNA polymerase
• In which direction does DNA polymerase add nucleotides?

  In a 5' to 3' direction
• What did Meselson and Stahl's experiment demonstrate?

  DNA replication is semi-conservative
• What isotopes did Meselson and Stahl use in their experiment?

  Heavy nitrogen (15N) and light nitrogen (14N)
• What happens to DNA in a centrifuge after replication?

  It settles based on nitrogen weight
• What is the significance of the DNA settling in the middle of the centrifuge tube?

  It shows a mixture of heavy and light DNA