Download Experiment 1: Coding Procedure A) Using red, blue, yellow and

Experiment 1: Coding
Materials
For the following exercises:
Red beads
Blue beads
Yellow beads
Green beads
Regular beads are used as
nucleotides
Pop-it beads are used as amino
acids
Procedure
A) Using 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:
R:R:R
B:B:B
Y:Y:Y
G:G:G
R:B:Y
B:Y:G
M:
O:
S:
T:
U:
G:Y:B
Y:B:R
R:B:G
B:R:Y
G:B:R
Create
codons for:
Start:
Stop:
Space:
Y:R:G
B:G:Y
R:G:R
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B)
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
YRG BRY YYY BBB RGR GYB YBR GBR RBG BBB RGR BYG GGG RBY BBB RBG
RGR GYB YBR RBG BRY RGR RRR YYY BBB BBB RBG BBB BGY
Used 87 beads
1. 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.
YRG BRY YYY BBB RGR GYB YBR GBR RBG BBB RGR BYG GGG RBY BBB RBG RGR
RRR YYY BBB BBB RBG BBB BGY
2. What does the sentence say now? (re-read the entire sentence)
The sentence now says: The mouse likes cheese
Mutations are simply changes in the sequence of nucleotides. There are three ways this occurs:
Change one, remove one, or add one
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Using the sentence from exercise 1B:
C) Change the 24th bead to a different color.
3. What does the sentence say now? (re-read the entire sentence)
YRG BRY YYY BBB RGR GYB YBR GB*B* RBG BBB RGR BYG GGG RBY BBB RBG
RGR GYB YBR RBG BRY RGR RRR YYY BBB BBB RBG BBB BGY
The 24th bead was R, and then changed to a B [between the asterisks]. The
sentence now says: The mo_se likes most cheese. [I used _ because GBB does
not correspond to any letters above]
4. Does it make sense?
Most of it still makes sense, except for the word mo_se
D) Replace the 24th bead and remove the 20th bead (remember what was there).
5. What does the sentence say (re-read the entire sentence)?
YRG BRY YYY BBB RGR GYB Y*RG BRR BGB BBR GRB YGG GGR BYB BBR BGR
GRG YBY BRR BGB RYR GRR RRY YYB BBB BBR BGB BBB GY
Now the sentence says: [blanks are codons with no corresponding amino acids.
there are no spaces between the blanks!]
[START] The m[START] _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ e _ _ e
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6. Does it make sense?
No, it does not make any sense because the deletion of the 20th bead shifted
all of the original codons
7. Where does it make sense?
Only the beginning of the sentence makes sense, before the removal of the
20th bead.
E) Replace the 20th bead and add one between bead numbers 50 and 51.
8. What does the sentence say?
YRG BRY YYY BBB RGR GYB YBR GBR RBG BBB RGR BYG GGG RBY BBB RBG
RG*B* RGY BYB RRB GBR YRG RRR RYY YBB BBB BRB GBB BBG Y
The sentence says: [blanks are codons with no corresponding amino acids.
there are no spaces between the blanks!]
The mouse likes_ _ _ _ u[START]c _ _ e _ _ _
9. Does it make sense?
No, it does not make any sense because the addition of a bead shifted all of
the original codons
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10. In “C” we mutated one letter. What role do you think the redundancy
of the genetic code plays, in light of this change?
The redundnacy of the genetic code means that if one letter is mutated in a
codon, the mutated codon may still code for the same amino acid. This is
important because it prevents mutations from becoming deleterious.
11. Based on your observations, why do you suppose the mutations we
made in “D” and “E” are called frame shift mutations.
The mutations in D and E are called frameshift mutations because they shift
the reading frame of the codons either to the left or the right
12. Which mutations do you suspect have the greatest consequence?
Why?
Frameshift mutations have the greatest consequence, because everything
after the mutation is shifted and potentially will not make any sense.
DNA codes for all of the proteins manufactured by any organism (including you!). It is valuable,
highly informative and securely protected in the nucleus of every cell.
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