Final answer:
None of the provided answer choices accurately represents a DNA mutation on the template strand that would change serine to cysteine since they do not involve changes that would lead to mRNA with codons UGU or UGC, which code for cysteine.
Step-by-step explanation:
The question presented relates to a DNA mutation that would change the amino acid serine to cysteine. Serine is encoded by the codons AGU and AGC on mRNA, while cysteine is encoded by UGU and UGC. Keeping in mind that the question specifies a mutation in the template strand of DNA, and given that mRNA is synthesized using the template strand as a guide, option (c) AGU to UGU represents the correct answer. This is because the AGU codon for serine on the template strand would pair with UCA on mRNA, and changing AGU to UGU on the template strand would result in ACA on mRNA, which codes for threonine instead of cysteine. Option (c) is incorrect because UGU would pair with ACA, not the initial sequence AGU on the template strand. Thus, none of the answer choices directly converts serine to cysteine based on a mutation in the template strand.
A correct mutation converting serine (AGU or AGC on mRNA) to cysteine (UGU or UGC) on the mRNA would need to involve changing the DNA template strand nucleotide that pairs with the first position in the serine codon from an 'A' to a 'G' (complementing the mRNA 'U' to 'C' change). However, none of the provided answer choices accurately describe this. Therefore, none of the provided answer choices is correct.