Docstoc

Lab 3 DNA Forensics Exercise 1 DNA Replication Lab Objective to

Document Sample
Lab 3 DNA Forensics Exercise 1 DNA Replication Lab Objective to Powered By Docstoc
					Exercise 1: DNA Replication Lab

Objective: to understand how probability can be used to demonstrate the need for DNA
replication machinery.

Materials: Cut craft sticks with foamies attached in four colors each corresponding to
different bases (adenine, guanine, thymidine, cytosine).

Your ziplock bag contains 100 game pieces (halved craft sticks). The sticks have
different color foamies attached to them. The four colors of represent each of the four
bases that make up a DNA strand. First draw out 25 game pieces and place them on the
table in front of you in the order that you drew them from the bag. The color code for the
bases is listed on the front of your ziplock bag.

Record your DNA sequence in the worksheet provided. When you have finished answer
the questions below.

   1. What is the percentage of each of the four colored bases in the DNA strand in part
      one of the lab exercise?




   2. Average your data for each of the four colors with everyone else’s in the class.
      What do you think the actual percentage of the colors was in the group of popsicle
      sticks you had?




   Adenine always pairs with thymidine and cytosine always pairs with guanine. Your
   task now is to synthesize the complementary strand of DNA. Draw out a game piece
   from the bag and see if it is complementary to the first base in your sequence. If it is
   not, put the piece back in the bag and draw again. Keep drawing until you get the
   complimentary base. When you do, record how many times you had to draw to get
   the correct base in the worksheet. When you have finished, answer the questions
   below.
3. How many tries did you expect it would take to get the “complimentary” base to
   the DNA sequence from part one?




4. On average how many tries did it take to get the “complimentary” base in part
   one?




5. Do you notice any pattern in the data you collected on the number of tries it takes
   to get a complimentary base? If so what is the pattern you observed.




6. What do you think causes this pattern?




7. Can you name a common biological or molecular process that also has this
   pattern?
Nucleotide sampling exercise 2

You have been given a second bag containing game pieces. The proportion of the game
pieces is different than in the first bag. The rules are the same as for the previous
exercise. Draw 25 game pieces and record the DNA sequence. Answer questions 1 and
two. Then make the complementary DNA strand, record how many tries it takes and
proceed to the rest of the questions.

   1. What is the percentage of each of the four colored bases in the DNA strand in part
      one of the lab exercise?




   2. Average your data for each of the four colors with everyone else’s in the class.
      What do you think the actual percentage of the colors was in the group of popsicle
      sticks you had?




   3. How many tries did you expect it would take to get the “complimentary” base to
      the DNA sequence from part one?




   4. On average how many tries did it take to get the “complimentary” base in part
      one?
   5. Do you notice any pattern in the data you collected on the number of tries it takes
      to get a complimentary base? If so what is the pattern you observed.




   6. What do you think causes this pattern?




   7. Can you name a common biological or molecular process that also has this
      pattern?




How would the difference in nucleotide composition between sampling exercise one and
two affect the genome sequence?

				
DOCUMENT INFO
Shared By:
Categories:
Stats:
views:51
posted:10/28/2010
language:English
pages:4
Lingjuan Ma Lingjuan Ma MS
About work for China Compulsory Certification. Some of the documents come from Internet, if you hold the copyright please contact me by huangcaijin@sohu.com