Questions-3 NAN

• What doe DNA stand for?

  Deoxyribonucleic acid
• What does RNA stand for?


  Ribonucleic acid.
• What are the monomers for DNA and RNA?

  nucleotides.
• What are the three general components for a nucleotide?

  a phosphate , pentose sugar and nitrogen containing base
• What are the four organic bases in DNA?

  Adenine, Thymine, Guanine, Cytosine
• what type of bond is formed by two adjacent nucleotides?

  phosphodiester bond.
• what shape is a DNA molecule?

  double-stranded double helix.
• which bonds keep DNA strands together?

  hydrogen bonds
• describe the structure of RNA?

  relatively short single stranded polynucleotide chain.
• what is the first stage in DNA replication?

  unwinding the double helix using DNA helicase.
• what is the role of DNA helicase?

  breaks hydrogen bonds between complementary bases.
• what does DNA polymerase do in replication?

  joins adjacent nucleotides to form phosphate backbone.
• how many hydrogen bonds form between thymine and adenine?

  2 hydrogen bonds
• how many bonds form between guanine and cytosine?

  3 hydrogen bonds
• how do you obtain DNA fragments using electrophoresis

  -use of restrictions enzymes

  -use of buffer

  -place DNA in sample wells at negative cathode

  -shorter fragments move towards anode faster than larger fragments