Question

Experiment 1 - Coding

ab 13DNA and RNA xperiment 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 Yellow Beads Blue Beads Green Beads Procedure: 1. 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: H: K: L: M: O: S: T: U: Create codons for: Start: Stop: Space: 2. 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 a. 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 9 2013 eScience Labs, LLC. All Rights Reserved Science Labs ab 13DNA and RNA here, but as an illustration of this "alternate splicing", remove codons (beads) 52 - 66 from your sentence above b. 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: 1. Change a nucleotide(s) 2. Remove a nucleotide(s) 3. Add a nucleotide(s) 3. Using the sentence from exercise 21B: Change the 24th bead to a different color. What does the sentence say now (re-read the entire sentence)? Does the sentence still make sense? a. Replace the 24th bead and remove the 20th 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? b. Replace the 20th bead and add one between bead numbers 50 and 51. What does the sentence say now? Does the sentence still make sense? c. d. 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? Based on your observations, why do you suppose the mutations we made in 3.b and 3.c are called frame shift mutations? e. f. Which mutations do you suspect have the greatest consequence? Why? 9 2013 eScience Labs, LLC. All Rights Reserved Science Labs

Answer 1

For this experiment, there are many possible answers as the colors chosen can be different from one person to another. But you can use this explanation as example Using colored beads: Red beads (R), Blue beads (B), Yellow beads (Y), Green beads (G),

1. Devise and lay out a three colors code for each letter: C: RBY E: BYG H: YGR :GRB K: RYG L: BGR M: YRB O: GBY S: RBG T: BYR U: YGB START: GRY STOP: RYB SPACE: BGY

2. The mouse likes most cheese: GRBYGBYGRBGBYGRYB How many beads? 87 a. b. Instead of The mouse likes most cheese, now the sentence reads GRYBYRYGRBYGBGYYRBGBYYGBRBGBYGBGYBGRGRBRYGBYGRBGBGY-YRBGBYRBGBYRBGY RBYYGRBYGBYGRBGBYGRYB GRYBYRYGRBYGBGYYRBGBYYGBRBGBYGBGYBGRGRBRYGBYGRBGBGYRBYYGRBYGBYGRBGBYGR YB THE MOUSE LIKES CHEESE

3. Using the sentence from 2B: Change the 24th bead to a different color. What does de sentence say now? Does the sentence still make sense? a. GRYBYRYGRBYGBGYYRBGBYYGRRBGBYGBGYBGRGRBRYGBYGRBGBGYRBYYGRBYGBYGRBGBYG RYB It reads: THE MOHSE LIKES CHEESE The sentence doesn't make sense anymore.

Replace the 24th bead and remove the 20th. What does the sentence say? Does the sentence still make sense? If it doesn't make sense, are there any words that do? If so, what words still make sense? b. The sentence reads: THE MXXXUXXXUHXXXIUHXHX Where X are triplets that don't match any letter. The sentence doesn't make sense anymore Only "The " makes sense in the sentence

c. Replace the 20th bead and add one between 50 and 51. What does the sentence say? Does the sentence still make sense? GRYBYRYGRBYGBGYYRBGBYYGBRBGBYGBGYBGRRBRYGBYGRBGBGRYRBYYGRBYGBYGRBGBY GRYB The sentence reads: THE MOUSE LIKESLMXCOIO It doesn't make sense anymore

d. In 3a. what role do you think the redundancy of the genetic code plays in this type of change? The redundancy in the genetic code means that different codons (triplets of beads) can encode the same amino acid (letter). So, in real life if one nitrogenous base is changed for another, it may be possible that the same amino acid is formed; which won't have any effect in the individua Why do you suppose the mutations made in 3b. and 3c. are called frame shift mutations? e. They are called frame shift mutation because when you add or replace a bead, the reading of the codons changes completely. f. Which mutations do you suspect have the greatest consequence? Why? Frame shifting mutations have the greatest consequence because it changes the code completely. They form totally different letters (amino acids) which can cause the mis production of some proteins or the production of different ineffective proteins in the organism.