Question

7. A gene has a base sequence of GTC. Due to a mutation, the base sequence changes to GTG. Answer the following questions using the codon table below.

a) What are the bases of mRNA coded for by this section of DNA, before the mutation? (1 point)

b) What are the bases of mRNA coded for by this section of DNA, after the mutation? (1 point)

c) What amino acid is coded for by this sequence before the mutation? (1 point)

d) What amino acid is coded for by this sequence after the mutation? (1 point)

e) Is this is a silent mutation or a missense mutation? Explain. (1 point)

g) If the strand of DNA with the sequence GTA mutated to GTG, would this be a silent or missense mutation? (1 point)

h) If the strand of DNA with the sequence TTA mutated to TTG, would this be a silent or missense mutation? (1 point)

i) If the strand of DNA with the sequence TGA mutated to GGA, would this be a silent or missense mutation? (1 point)

8. A gene has a base sequence that begins with TAA CTA TGA CGT CG. Answer the following questions using the codon table from question 7.

a) What RNA sequence would be produced during transcription? (1 point)

b) What are the first four amino acids coded by this sequence? (1 point)

c) The gene has a frameshift mutation, where the fifth base in the sequence is deleted. Write the new DNA base sequence. (1 point)

d) What is the new RNA sequence? (1 point)

e) What are the first three amino acids coded by this new mutated sequence? (1 point)

f) How does the correct amino acid sequence compare to the mutated sequence? (1 point)

Answer 1

7.

Answer:

a) CAG

b) CAC

c) Gin.

d) His.

e) This is a missense mutation because the original gene sequence produced a different mRNA base sequence than the mutated gene sequence. The different mRNA base sequences code for two different amino acids. For humans, this can cause accumulation of the wrong protein needed in the body, which can be harmful in the future.

g) Silent mutation

h) Silent mutation

i) Missense mutation

8.

Answer:

a) AUU GAU ACU GCA GC

b) Lie. Asp. Thr. Ala.

c) TAA CAT GAC GTC G

d) AUU GUA CUG CAG C

e) Lie. Asp. Leu.

f) "You can answer this..."

7.

Step-by-step explanation:

a)

Base pairing rule:

• Adenine (A) only pairs with Uracil (U)
• Thymine (T) only pairs with Adenine (A)
• Guanine (G) only pairs with Cytosine (C), and vice versa.

b) "Go back to 7a)"

c)

Note: Only use the mRNA codons to determine the amino acids.

How to read the Codon Table (Look at attachment for an example):

1. Search for first mRNA base in the codon.
2. Search for second mRNA base in the codon.
3. Search for third mRNA base in the codon.

d) "Go back to 7c)"

e)

Missense mutation vs. silent mutation:

• Both types of mutation will produce a mRNA base sequence different from the mRNA base sequence produced by a healthy gene.
• Missense mutation's mRNA codon will produce a different amino acid than the mRNA codon of a healthy gene. (Harmful)
• Silent mutation's mRNA codon will produce the same amino acid as the mRNA codon of a healthy gene. (Unharmful)

g) "Go back to 7e)"

h) "Go back to 7e)"

i) "Go back to 7e)"

8.

Step-by-step explanation:

a) "Go back to 7a)"

b) "Go back to 7c)"

c) Thymine (T) in the second codon is deleted. Therefore, shift all bases to the left one space.

d) "Go back to 7a)"

e) "Go back to 7c)"