Why are telomeres necessary in eukaryotes but not prokaryotes?
To prevent the loss of genes as chromosome ends wear down, the tips of eukaryotic chromosomes have specialized DNA “caps” called telomeres. … Telomeres need to be protected from a cell’s DNA repair systems because they have single-stranded overhangs, which “look like” damaged DNA.
Why do eukaryotic chromosomes have telomeres and bacterial chromosome do not?
Bacteria and viruses possess circular DNA, whereas eukaryotes with typically very large DNA molecules have had to evolve into linear chromosomes to circumvent the problem of supercoiling circular DNA of that size. Consequently, such organisms possess telomeres to cap chromosome ends.
Why do prokaryotes not have telomerase?
The “end replication problem” is exclusive to linear chromosomes as circular chromosomes do not have ends lying without reach of DNA-polymerases. Most prokaryotes, relying on circular chromosomes, accordingly do not possess telomeres.
How are chromosomes different in prokaryotic and eukaryotic cells?
Eukaryotic chromosomes are larger than that of prokaryotes. Prokaryotic chromosome contains a covalently closed circular DNA (cccDNA). Each eukaryotic chromosome contains a linear DNA with two ends. Prokaryotic chromosomes codes for few proteins.
What do telomeres do in eukaryotes?
Telomeres are the physical ends of eukaryotic chromosomes. They protect chromosome ends from DNA degradation, recombination, and DNA end fusions, and they are important for nuclear architecture. Telomeres provide a mechanism for their replication by semiconservative DNA replication and length maintenance by telomerase.
Why are telomeres problematic for eukaryotic chromosome replication?
Why are telomeres problematic for eukaryotic chromosome replication? Removal of the lagging strand primer leaves a gap in the one of the strand’s DNA sequences.
Why don t prokaryotic chromosomes have centromeres and telomeres?
Prokaryotic cells typically have a single, circular chromosome located in the nucleoid. Since prokaryotic cells typically have only a single, circular chromosome, they can replicate faster than eukaryotic cells. … Each time a typical or somatic eukaryotic cell divides, the telomeres get shorter.
Are telomeres found in prokaryotes and eukaryotes?
Eukaryotes have solved the end-replication problem by locating highly repeated DNA sequence at the end, or telomeres, of each linear chromosome. … Most prokaryotes with circular genome do not have telomeres.
Why do bacterial chromosomes not have telomeres?
Bacteria don’t need telomerase because their chromosomes don’t have telomeres. Most bacterial chromosomes are circular, meaning they have no end.
How does DNA replication differ between eukaryotes and prokaryotes?
The prokaryotic DNA replication is a continuous process and occurs throughout the cell cycle. The eukaryotic DNA replication occurs during the S phase of the cell cycle. The DNA molecule in prokaryotic cells is double-stranded and circular in shape.
What are the telomeres and why are they important?
Telomeres, the specific DNA–protein structures found at both ends of each chromosome, protect genome from nucleolytic degradation, unnecessary recombination, repair, and interchromosomal fusion. Telomeres therefore play a vital role in preserving the information in our genome.
Do bacterial chromosomes contain telomeres?
Although much less commonly appreciated, linear chromosomes and telomeres are not exclusive to the eukaryotic kingdom; they can be found in a number of bacteria, including Streptomyces, Borrelia, Rhodococcus, etc.