2.1 - Structure of DNA and RNA

• 2 common types of nucleic acids ?

  DNA and RNA
• What’s the function of DNA ?

  holds genetic info in all living cells
• What’s the function of RNA ?

  transfers genetic info from DNA to the ribosomes
• What are ribosomes made of ?

  RNA and protein
• DNA and RNA are polymers of…

  Nucleotides
• What 3 components forms nucleotides ?

  Phosphate group, Pentose, Nitrogen-containing base
• What are the pentose sugars in DNA and RNA ?

  deoxyribose and ribose
• What is the bond between 2 nucleotides called ?

  Phosphodiester bond
• How are phosphodiester bonds created ?

  Condensation reactions between 2 nucleotides
• What’s the bond between the pentose and phosphate ?

  Ester bond
• What’s the bond between the pentose and the base ?

  Glycosidic bond
• What are the 2 types of bases ?

  Pyrimidines and purines
• Describe a DNA molecule ?

  A double helix with 2 polynucleotide chains held together by hydrogen bonds between specific complementary base pairs
• Is the RNA molecule short or long ?

  Relatively short polynucleotide chain
• Why did scientists doubt that DNA carried the genetic code ?

  Its relatively simple structure
• 4 differences between DNA and RNA ?

  DNA is double stranded, RNA is single

  Deoxyribose sugar, ribose sugar

  1 type, 3 types

  Has thymine bases, has uracil
• How many bonds do the DNA base pairs form between them?

  G and C form 3

  A and T form 2
• What are the purine and Pyrimidine bases ?


  Purine - adenine and guanine

  Pyrimidine - cytosine and thymine or uracil for RNA
• Who worked out the structure of DNA ?

  Watson and Crick with help from Rosalind Franklin
• 2 reasons why DNA is a stable molecule ?

  Phosphodiester backbone protects chemically reactive organic bases

  Many hydrogen bonds create strength, especially G and C pairings as there’s 3 bonds