Mutations Wrap Up

There were a couple of you that still needed to present your slides so I had you do that.  We started class with the following daily questions though.  This is a good wrap up for mutations and how they affect not only the RNA sequence, but consequently the protein itself.

Wednesday April 25^th

In a frameshift mutation, which would cause more harm to the protein the addition on 1 nucleotide or the addition of 6 nucleotides?Why?

Adding just one - when adding nucleotides in sets of three you are just adding another amino acid instead of moving everything down (unless of course you add three in the middle of a codon)

*Mutations such as missense and nonsense would occur during which of these processes?

** During DNA Replication or Transcription.  These types of mutations are changes in the actual DNA or RNA sequence - therefore it could only happen when DNA or RNA is MADE.  So during DNA replication if the DNA Polymerase doesn't do a good job of "proof-reading" that will change the DNA which then during transcription will be coded into mRNA with that same mistake. 

*Mutations such as translocation and nondisjunction would occur during which of those?

Meiosis - these are when crossing-over goes "Wrong" or when chromosomes do not fully separate from each other. 

A couple last things then that I discussed.  First, we have talked about mutations that have no effect (silent mutations) and those that cause LARGE changes in the protein shape that are harmful; but a key thing to understand is that some mutations are actually advantageous!!  We will talk more about this in the next chapter and you will see how this all just flows together.  If no mutations ever occurred then there would only really be two sets of genes that ALL of us had (from the first male/female).  The word Mutation often times gets a bad wrap when really ANY change in the DNA is a mutation.  So different alleles are just different "mutations" which ultimately give us the variety in traits that we have today.

Tomorrow will be our formal review - I have almost finished typing it up so feel free to check it out tonight but here is a run down of the content that we have covered this chapter.

*DNA Structure

*DNA Replication

*Transcription

*Translation

*Mutations