What happens as a direct result of a loss of function mutation in telomerase?

What happens as a direct result of a loss of function mutation in telomerase?

• A. The ends of DNA chromosomes will be shortened
• B. The ends of the RNA transcript will have a shorter polyA tail
• C. The ends of the RNA transcript will have a longer polyA tail
• D. The ends of DNA chromosomes will be extended

Answer: (A)

The correct answer is that the ends of DNA chromosomes will be shortened as a direct result of a loss of function mutation in telomerase. Telomerase is an enzyme that adds repetitive nucleotide sequences, known as telomeres, to the ends of eukaryotic chromosomes. These telomeres protect the ends of the chromosomes from degradation and prevent them from fusing with each other. When telomerase is dysfunctional due to a loss of function mutation, it can no longer add the necessary telomeric repeats to the chromosome ends. This results in the progressive shortening of telomeres with each cell division. Eventually, critically short telomeres lead to cellular senescence or apoptosis, which can contribute to aging and the development of age-related diseases. The other options refer to aspects of RNA transcription and processing, which are not directly related to the function of telomerase. The shortening of the RNA transcript's polyA tail or its extension does not have a direct correlation with the activities of telomerase or the structural integrity of DNA chromosomes. Thus, these do not address the specific effects of telomerase mutations on DNA chromosome length.

The correct answer is that the ends of DNA chromosomes will be shortened as a direct result of a loss of function mutation in telomerase. Telomerase is an enzyme that adds repetitive nucleotide sequences, known as telomeres, to the ends of eukaryotic chromosomes. These telomeres protect the ends of the chromosomes from degradation and prevent them from fusing with each other.

When telomerase is dysfunctional due to a loss of function mutation, it can no longer add the necessary telomeric repeats to the chromosome ends. This results in the progressive shortening of telomeres with each cell division. Eventually, critically short telomeres lead to cellular senescence or apoptosis, which can contribute to aging and the development of age-related diseases.

The other options refer to aspects of RNA transcription and processing, which are not directly related to the function of telomerase. The shortening of the RNA transcript's polyA tail or its extension does not have a direct correlation with the activities of telomerase or the structural integrity of DNA chromosomes. Thus, these do not address the specific effects of telomerase mutations on DNA chromosome length.