Concept explainers
Suppose a triplet on the template strand of a piece of DNA has the sequence 5′-ATA-3′. What would be the consequences if the sequence were mutated to GTA? TTA? GCA? Explain your answer in each case.
To determine: The consequences if a sequence 5ʹ-ATA-3ʹ on template strand of DNA has been mutated to GTA.
Introduction: The specific sequences which are present on template strand of DNA (Deoxyribose nucleic acid) in the form of triplet codons will transmit the information for the formation of messenger RNA (Ribose nucleic acid) and proteins.
Explanation of Solution
When a sequence of 5ʹ-ATA-3ʹ on template strand of DNA has been mutated to GTA, it will lead to the formation of messenger RNA having triplet codons UAC in 3' to 5' direction. It occurs because if ATA was present, the resulting messenger RNA would be UAU. Therefore, due to the mutation, UAC will code for amino acid tyrosine similar to UAU because of both UAU and UAC code for amino acid tyrosine.
(b)
To determine: The consequences if a sequence 5ʹ-ATA-3ʹ on template strand of DNA has been mutated to TTA.
Introduction: The specific sequences which are present on template strand of DNA (Deoxyribose nucleic acid) in the form of triplet codons will transmit the information for the formation of messenger RNA (Ribose nucleic acid) and proteins.
Explanation of Solution
When a sequence of 5ʹ-ATA-3ʹ on template strand of DNA has been mutated to TTA, it will lead to the formation of messenger RNA having triplet codons UAA in 3' to 5' direction. It occurs because if ATA was present, the resulting messenger RNA would be UAU. Therefore, due to the mutation, UAA will code for stop codon instead of tyrosine that would be coded by UAU.
(c)
To determine: The consequences if a sequence 5ʹ-ATA-3ʹ on template strand of DNA has been mutated to GCA.
Introduction: The specific sequences which are present on template strand of DNA (Deoxyribose nucleic acid) in the form of triplet codons will transmit the information for the formation of messenger RNA (Ribose nucleic acid) and proteins.
Explanation of Solution
When a sequence of 5ʹ-ATA-3ʹ on template strand of DNA has been mutated to GCA, it will lead to the formation of messenger RNA having triplet codons UGC in 3' to 5' direction. It occurs because if ATA was present, the resulting messenger RNA would be UAU. Therefore, due to the mutation, UGC will code for amino acid cysteine instead of tyrosine that would be coded by UAU.
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Chapter 18 Solutions
BECKER'S WORLD OF THE CELL-W/ACCESS
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