Mutations

Today's focus was on mutations to the DNA.  The two main categories for mutations are base-pair (or point) mutations and insertions/deletions.  Base pair substitutions may result in silent, missense or nonsense codons.  Insertions and deletions (unless they involve multiples of 3 nucleotides) result in a frameshift.  The impact of mutations depends upon the type and location of the mutation.  Several examples of genetic diseases based on missense mutations were discussed.  A few that were named were: sickle-cell anemia, cystic fibrosis and Tay-Sachs.  You can learn more about each of these genetic diseases, as well as others at http://www.ygyh.org/

Here are some great links about mutations:

• A very nice look at why a base-pair substitution may occur.
• http://highered.mcgraw-hill.com/sites/0072556781/student_view0/chapter11/animation_quiz_3.html
• An explanation of deletions and insertions
• http://highered.mcgraw-hill.com/sites/0072556781/student_view0/chapter11/animation_quiz_4.html 
• A focus on thymine dimers caused by UV light.
• http://highered.mcgraw-hill.com/sites/0072556781/student_view0/chapter11/animation_quiz_5.html

Homework
Your homework tonight is to read pp. 359-361 and then take a look at the animations (there is also a good one in Ch. 19 of your textbook's website).  Then answer this one question: How does all of the DNA fit into the nucleus in an organized way?

http://www.pbs.org/wgbh/nova/genome/dna.html
http://www.biostudio.com/demo_freeman_dna_coiling.htm