Expert: Walter Hintz - 2/17/2006

Question
hello, how are you? I was wondering if you can explain to me this question. I am a independent AP student i would like some help.
    a) Describe in a brief paragraph the characteristics of mutation.
    b) List the various alterations in the hereditary material that result in
         mutations. Illustrate with a simple diagram.
    c) Discuss the ways in which one of the alterations that you list in part b) causes
         hereditary changes.

Answer
Hi bm:
It is difficult to answer this question briefly since I am unaware about what you already know about DNA and genetic changes.  All I can do is give you a short outline and if you do notunderstand something you will have to get back to me.
a) First of all a mutation is an alteration in the DNA.  DNA consists of a sequence of four different nucleotides and this sequence constitutes a code that is eventually translated by the synthesis of proteins. A mutation is a change in the sequence.
b)I do not know how to make a diagram on a computer but I can give you a practical example of the effects of a mutation.  The DNA acts as a template for the production of RNA and the RNA acts as  template for protein synthesis. A protein as you know is made up of amino acids and the amino acid sequence determines the type of protein. A very large protein, the hemoglobin molecule consists of two chains on AAs (a beta chain 146 AAs and an  alpha chain of 142 AAs)In normal hemoglobin there is glutamic acid (an AA) in the 6th position but in some circumstances a valine replaces it.  The result is sickle cell disease. Why is their a substitution?  Because there is a mutant gene resulting in a change in the DNA which transcribes an change in the RNA which translates the amino acid valine in the beta chain sequence.  I believe this also answers (c)