DNA structure

• What are the monomers that make up DNA called?

  Nucleotides
• What are the components of a nucleotide?

  Central sugar, nitrogenous base, phosphate group

  
• What sugar is found in DNA nucleotides?

  Deoxyribose

  
• What are the components of a DNA nucleotide?

  A central sugar molecule (deoxyribose), a nitrogenous base (A, T, C, or G), and a phosphate group

  
• What is the structure of the DNA molecule?

  Two strands of nucleotides twisted into a double helix

  
• How are the individual strands of the DNA molecule formed?

  The phosphate groups of the nucleotides form covalent bonds with the deoxyribose molecules of adjacent nucleotides

  
• Why is it easier to separate DNA strands with lots of A-T base pairs compared to those with lots of G-C base pairs?

  Because the A-T base pairs are held together by 2 hydrogen bonds, while the G-C base pairs are held together by 3 hydrogen bonds
• What are the two categories of nitrogenous bases in DNA and RNA?

  Purines (Guanine and Adenine) and pyrimidines (Cytosine, Thymine, and Uracil)

  
• What is the basis for the complementary base pairing in DNA?

  Adenine pairs with thymine, and cytosine pairs with guanine, through hydrogen bonding

  
• How many hydrogen bonds are formed between A-T and G-C base pairs?

  A-T base pairs are held together by 2 hydrogen bonds, while G-C base pairs are held together by 3 hydrogen bonds
• What is the structural difference between purines and pyrimidines?

  Purines have a double ring structure, while pyrimidines have a single ring structure

  
• What is the relationship between the types of nitrogenous bases in complementary base pairs?

  Each complementary base pair consists of one purine and one pyrimidine
• What are the key features of the DNA molecule structure?

  • Two strands of nucleotides twisted into a double helix
  • Nucleotides consist of a deoxyribose sugar, a phosphate group, and a nitrogenous base (A, T, C, G)
  • Strands held together by complementary base pairing (A-T, G-C)
  • A-T pairs have 2 hydrogen bonds, G-C pairs have 3 hydrogen bonds
  • Purines (G, A) have double ring structure, pyrimidines (C, T, U) have single ring structure

  
• What are the key differences between purines and pyrimidines in DNA and RNA?

  • Purines (G, A) have a double ring structure, pyrimidines (C, T, U) have a single ring structure
  • In DNA, the pyrimidine is thymine (T), in RNA it is uracil (U)
  • Each complementary base pair consists of one purine and one pyrimidine

  
• How does the structure of DNA allow it to be replicated and transcribed?

  The weak hydrogen bonds between the complementary base pairs allow the DNA strands to be separated during replication and transcription