Which of the following statements about telomeres is...

Which of the following statements about telomeres is incorrect? a) They function like a counter, keeping track of how many times a cell has divided. b) At birth, they are long enough to permit approximately 50 cell divisions in most cells. c) They are slightly shorter in prokaryotic cells than in eukaryotic cells. d) They function like a protective cap on chromosomes. e) They contain no critical genes.

Which of the following statements about telomeres is incorrect?

a) They function like a counter, keeping track of how many times a cell has divided.
b) At birth, they are long enough to permit approximately 50 cell divisions in most cells.
c) They are slightly shorter in prokaryotic cells than in eukaryotic cells.
d) They function like a protective cap on chromosomes.
e) They contain no critical genes.

Key Concepts

Telomeres

Telomeres are repetitive nucleotide sequences found at the ends of linear chromosomes in eukaryotes. They serve as protective caps that prevent chromosomes from deteriorating or fusing with neighboring chromosomes, thereby maintaining genomic stability.

Cell Division and Telomere Shortening

During each cell division, telomeres shorten because the DNA replication mechanism cannot completely replicate the ends of linear chromosomes. This progressive shortening acts like a cellular division counter, eventually signaling the cell to cease dividing once telomeres reach a critically short length.

Telomerase

Telomerase is an enzyme that adds telomeric repeat sequences to the ends of chromosomes. It is active in certain cell types, such as stem cells and cancer cells, where it helps maintain telomere length and allows for continued cell division.

Eukaryotic versus Prokaryotic Chromosomes

Eukaryotic chromosomes are linear and contain telomeres, which are essential for protecting chromosome ends. In contrast, prokaryotic cells typically have circular chromosomes that do not require telomeres, as their replication mechanisms differ substantially from those of eukaryotes.

Genomic Organization in Telomeres

Telomeres are composed of non-coding repetitive DNA sequences and do not house critical genes. This structural organization serves to protect the essential coding regions of the chromosome during replication, as they buffer against the loss of important genetic information.

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