DNA and RNA

• nucleotides are the monomers of nucleic acids such as DNA and RNA.
• nucleotides are monomers that can join together to form dinucleotides or polynucleotides.
• a nucleic acid is the functional molecule made up of one or more polynucleotide chains.
• what are the components of a nucleotide?

  a pentose sugar, phosphate group and a nitrogenous base.
• when nucleotides join together via condensation reactions the phosphate group of one nucleotide joins to the pentose sugar on another forming a phosphodiester bond.
• Phosphodiester bonds can be broken via hydrolysis reactions, releasing the nucleotide monomers.
• DNA is a type of nucleic acid that contains the instructions needed to make proteins.
• what are the components of a DNA nucleotide?

  deoxyribose sugar, a phosphate group and a base (a, t, c or g)
• structure of DNA nucleotide: deoxyribose sugar, phosphate group, nitrogenous base

  
• what two scientist were credited with identifying DNA's structure?

  Watson and Crick
• what features of DNA enable genetic information to be passed from one generation to another?

  sugar phosphate backbone- protects coding bases on the inside of helix

  double stranded- allows strands to act as templates in DNA replication

  large molecule- stores lots of information

  double helix- makes molecule compact

  complementary base pairing- allows accurate DNA replication

  weak hydrogen bonds- strands can separate in DNA replication
• the four bases found in DNA can be grouped into 2 categories- purines or pyrimidines.
• what is the difference between purines and pyrimidines ?

  purines are larger bases that contain two carbon ring structures

  pyrimidines are smaller bases that contain one carbon ring structure
• adenine and thymine pair via 2 hydrogen bonds.
• cytosine and guanine pair via 3 hydrogen bonds.
• a smaller pyrimidine base will always bind to a larger purine base.
• why do smaller pyrimidines always bind to larger purine bases ?

  it maintains a constant distance between the 2 sugar-phosphate backbone.
• nucleotide structure

  A) phosphate group

  B) pentose sugar

  C) nitrogenous base

  
• polynucleotides diagram

  A) phosphodiester bonds

  B) sugar-phosphate backbone

  
• pyrimidines and purines:

  A) 2 rings

  B) purines

  C) pyrimidines

  
• RNA is a type of nucleic acid that use information from DNA to synthesis proteins.
• RNA structure:

  A) ribose

  B) A,U,C,G

  
• what are the 3 components that make up RNA?


  ribose, a phosphate group, and a base (A,U,C or G)
• RNA is a single stranded molecule made up of one polynucleotide strand.
• RNA molecules are much shorter than DNA molecules.
• comparison of DNA and RNA

  A) long

  B) 1

  C) 2

  D) ribose

  E) A,U,C,G