Experiment $1$: Coding

In this experiment, you will model the effects of mutations on the genetic code. Some mutations cause no structural or functional change to proteins while others can have devastating affects on an organism.

Materials

Red Beads

Blue Beads

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Yellow Beads

Green Beads

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Procedure:

Using the red, blue, yellow and green beads, devise and lay out a three color code for each of the following letters $($codon$).$ For example Z $=$ green : red : green.

In the spaces below the letter, record your $$code$.$

C:

E:

H:

I:

K:

L:

$\_\_\_$

$\_\_\_$

$\_\_\_$

$\_\_\_$

$\_\_\_$

$\_\_\_$

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M:

O:

S:

T:

U:

$\_\_\_$

$\_\_\_$

$\_\_\_$

$\_\_\_$

$\_\_\_$

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Create codons for:

Start:

Stop:

Space:

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$\_\_\_$

$\_\_\_$

$\_\_\_$

Using this code, align the beads corresponding to the appropriate letter to write the following sentence $($don$$t forget start, space and stop$)$: The mouse likes most cheese

How many beads did you use?

There are multiple ways your cells can read a sequence of DNA and build slightly different proteins from the same strand. We will not go through the process here, but as an illustration of this $$alternate splicing$,$ remove codons $($beads$)52-66$ from your sentence above.

What does the sentence say now? $($re$-$write the entire sentence$)$

Mutations are simply changes in the sequence of nucleotides. There are three ways this occurs:

Change a nucleotide$($s$)$

Remove a nucleotide$($s$)$

Add a nucleotide$($s$)$

Using the sentence from exercise $21$B:

Change the $24$th bead to a different color. What does the sentence say now $($re$-$read the entire sentence$)?$ Does the sentence still make sense?

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Replace the $24$th bead and remove the $20$th bead $($remember what was there$).$ What does the sentence say $($re$-$read the entire sentence$)?$ Does the sentence still make sense? If it doesn$$t make sense as a sentence, are there any words that do$?$ If so$,$ what words still make sense?

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Replace the $20$th bead and add one between bead numbers $50$ and $51.$ What does the sentence say now? Does the sentence still make sense?

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In $3.$a $($above$)$ you mutated one letter. What role do you think the redundancy of the genetic code plays in this type of change?

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Based on your observations, why do you suppose the mutations we made in $3.$b and $3.$c are called frame shift mutations?

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Which mutations do you suspect have the greatest consequence? Why?