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IB DNA Replication Lab

The process of DNA replication results an exact identical copy of the original DNA strand.  The process uses a number of different enzymes to complete the sequence.  DNA replication is completed during S Phase of Interphase in preparation for cell division.  

Purpose: Use nucleotide cut outs to simulate the process of DNA replication while identifying the different enzymes and molecules necessary to complete the process.  Use your notes, textbook, internet, etc. to help in walking through the process.  Take your time, it is important you can explain the multiple different steps.

Directions & questions:

  1. Make the left side of your DNA molecule by connecting the following nucleotides to form a vertical chain: cytosine (topmost), thymine, guanine, and adenine (bottommost).  Let this arrangement represent the left half of your DNA molecule.
  2. Make the right side of your DNA molecule by connecting the matching nucleotides to the left chain.  You will have to turn these nucleotides upside down in order to make them fit.
  1. What is the sequence of nitrogen bases for the right side of the DNA molecule?

  1. Where is this DNA located?

  1. Your finished model should now look like a ladder.
  1. What type of bonds connects the nitrogen bases together?

  1. To show replication, separate the left side from the right side, leave a space of about 12 cm wide between the two.  
  1. What enzyme separates the left side from the right side?

  1. You now have two strands of DNA.  Use the remaining nucleotides to create a complimentary copy of the left side strand of the original DNA strand. This is the leading strand
  1. What enzyme adds nucleotides to the old DNA strand?

  1. Where does replication begin?

  1. Circle which of the following statements that’s true.
  1. One daughter DNA molecule contains two old strands, while the other contains two new/copied strands.
  2. Each daughter DNA molecule contains one old strand and one new strand.
  1. Create a copy of the right side of the original DNA molecule; this is the lagging strand.
  1. Describe how the lagging strand is synthesized during replication.

  1. What are Okazaki fragments?

  1. How are Okazaki fragments joined together

  1. What molecule provides the energy to do so?

  1. Why are Okazaki fragments joined together?

  1. What is the complementary DNA nucleotides to the original right DNA strand?

  1. Using two different color markers, draw an original DNA strand (one color) followed by two daughter DNA molecules  (copied DNA will be a new color).

  1. Name and explain the model that explains the above replication in DNA.