Assignment 5

In the previous exercises we have considered alterations in hemoglobin structure created by base-pair substitution mutations in the globin gene. Working together in a group of four or five students or on your own, complete the following assignment which considers other types of mutations. Work within HemoglobinLab as you answer the questions below.


1 .		Select patient Juan Rodriquez. Click on the Blood Samples view and read his history. Note any differences in the color of Juan's blood compared with the control cells. Select the Microscope view and note the appearance of Juan's red blood cells compared with the control cells. Select the Gel Electrophoresis view and describe the electrophoretic pattern of Juan's hemoglobin. Based on this electrophoretic pattern, develop at least two hypotheses that could explain this observation.

2 .		To determine if any of your hypotheses are correct, select the Peptide Sequence view. Click on the Find Differences button. Compare the amino acid sequence of Juan's hemoglobin with the control sequence.

3 .		Once you have determined the first amino acid difference, refer to the codon chart in HemoglobinLab and identify the codon for the amino acid on the normal protein sequence. Select the Edit DNA Sequence view to modify this codon and recreate this mutation. Return to the Peptide Sequence view. Use the double arrows to examine the rest of Juan's hemoglobin. Record all differences in amino acid sequence that you observe in the field below.

4 .		Do the results of this examination confirm or refute your hypothesis? If necessary, formulate a new hypothesis to account for this observation.

5 .		Return to the Edit DNA Sequence view. Based on your hypothesis, alter the codon sequence of Juan's globin gene until you have identified the nucleotide change(s) that have occurred in Juan's globin gene.

6 .		What is an aplastic crisis? What are common causes of aplastic anemia? Consider Juan's patient history. How might his aplastic crisis have resulted from the hemoglobin mutation that he has? If necessary, refer to an anatomy and physiology textbook in your library to answer this question.