Part VI.  Assessment

1.  People with Sickle Cell Anemia have distorted red blood cells.  They make hemoglobin S instead of the normal hemoglobin A.  Hemoglobin S moves slower during electrophoresis.  Carriers of the disease make hemoglobin A and S.  Look at the gel below and answer the next three questions.                               

scagel
 Which lane was loaded with the sample from a person with sickle cell anemia?

  1. lane 1
  2. lane 2
  3. lane 3
  4. lane 4

Which lane was loaded with a sample from a normal person?

    1. lane 1
    2. lane2
    3. lane 3
    4. lane 4

Which lane contains a sample from a carrier for sickle cell anemia?

  1. lane 1
  2. lane 2
  3. lane 3
  4. lane 4

 

2.  Another Hemoglobin Genetic Variant:  Hemoglobin Saverne:

The normal DNA for the end of the beta chain of hemoglobin reads:

143
CAC AAG TAT CAC TAA GCT CGC TTT CTT GCT GTC CAA TTT CTA TTA

Fill in the second strand of DNA on the line above.

Make a messenger RNA from this second DNA strand:

 

Translate the mRNA into a protein until you reach the STOP signal; do not translate further – why?

            In the disease Hemoglobin Saverne, the A in triplet CAC #143 is deleted, causing a frameshift mutation.  Delete that A in triplet #143, and reorder the remaining bases downstream as triplets, three at a time, without that A.  The new DNA would then read:

143

Fill in the second strand of DNA above.

Now use the second strand of DNA to make the mRNA:

 

Translate the mRNA into protein; what is the result?

 

What effect do you think this would have on the functioning of the hemoglobin molecule? _____________________________________

 

3.  If you look up the HBB gene on the OMIM database, # 141900, you will see that other kinds of mutations in this gene result in different kinds of beta-thalassemias – what is the difference between sickle cell anemia and beta-thalassemias?

 

 

4.  Use the following terms to fill in the blanks below:  chromosome, DNA, gene, genome, protein.  The challenge is to use each term only once!

            The _______________ hemoglobin is coded by the _______ made of the molecule ___________ .    The genes are organized in the nucleus within _________________ , and all together they make up the entire human ________________.

 

 

Credits: Gel image and question compliments of Dennis Anderson, OCCC.

 

 

 

 

 

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