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Chapter 14 Blog: Mutation, DNA Repair, And Cancer (Garielle)

Page history last edited by Garielle Wagnac 13 years, 5 months ago


A.  Chapter Summary


The first section in the chapter discusses the different types of mutations that can occur. The effects of te mutations varies. If a base substitution were to occur in the third base of an amino acid sequence then there likely won't be an effect. Those mutations are called silent. A missense mutation changes an amino acid, this may alter protein function. If the change is between similar acids then there shouldn't be an effect but if not then there is a big problem. Nonsense codons changes one of the nucleotides causing for a stop codon to transcribed which will likely produce an ineffective gene. Frameshift totally messes up the transcription of a gene because either an addiction or deletion of a nucleotide occurs. This causes the mutated gene to be read differently than the original because the gene is read in 3s.


The second section of the chapter discusses DNA repair. There are 3 ways to repair DNA. The book focuses on direct repair and nucleotide excision repair. Direct repair is when an enzyme finds something wrong structure wise with the DNA and immediately converts it back to the correct structure. Nucleotide excision repair is when the mutated region is removed and is later filled in when DNA polymerase goes over the DNA.  Need help with understanding when each repair is used.


The third section of the chapter focuses on cancer.  Cancer is complicated. Cancer goes through this long precess before it is is cancer. It is a tumor first. When you find a tumor you hope for it to be benign because then it will not proceed to the cancerous stage. However, not everyone is lucky and the tumor can be malignant and if malignant is is called cancer. If you get cancer you really don't want it to be metastasis. All hell breaks loose there. Ahh! Here is where the whole oncogene and tumor suppressors gens come into place. Oncogenes are genes that help with cell growth that become mutated and the genes become overactive. Tumor suppressor genes are genes that encode proteins that prevent cancers but once these things become mutated there are no more prevention. It is a shame. Now for oncogenes to become mutated that is a whole other thing. It could happen through multiple things like the following: gene application, chromosomal translocation, chromosomal translocation, and retroviral insertion. Cancer is ridiculous! 


B. Useful Materials



  1. Causes of Oncogenic Chromosomal Translocation (02/06/11)- This article is perfect if you wanted to read an experiment of how the results showed that chromosomal translocation might need to be aided by other mutations for chromosomal mutation to really be a huge effect on the body concerning cancer. It is just interesting to read something like that after reading in the book made it seem like chromosomal translocation is huge cause of caner all by itself. Maybe this article is discussing the ripple effect of chromosomal translocation on the genes. Hmmm...confusing. 
  2. Nucleotide Excision Repair (02/06/11) - The is video is a good way to see the process that occurs and how it is different from DNA repair.  It is a silent video but there are many blurbs so it would be helpful to pause and read the blurbs to understand what is going on. 
  3. Cancer Website (02/06/11) - This is a god website for finding more information about oncogenes. There are pages about oncogenes and videos and articles are available for understanding oncogenes.  



Comments (1)

Derek Weber said

at 12:46 am on Feb 16, 2011

Let's talk about repair sometime. We can skype or talk after lab.

See comments for chapter 13 in regard to the summary.

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