Telomere_DNA_replication

Telomeres

Structures made from DNA sequences and proteins found at the ends of eukaryotic chromosomes.

Prokaryotic chromosome

A circular chromosome found in the cytoplasm.

Eukaryotic chromosome

A linear chromosome that is condensed around histone proteins and found in the nucleus.

Telomere sequence in humans

5’ TTAGGG 3’, repeated about 3,000 times.

Function of telomeres

They help organize chromosomes, protect the ends of chromosomes, and allow proper replication during cell division.

Critical length of telomeres

The point at which telomeres become too short and the chromosome can no longer be replicated, triggering cells to stop dividing.

Telomerase

An enzyme that adds guanine-rich repetitive sequences to maintain the length of telomeres.

Reverse transcriptase function of telomerase

Using an RNA template to produce complementary DNA at the 3’ end of eukaryotic chromosomal DNA.

Consequences of telomere shortening

When telomeres shorten, cells stop dividing, leading to tissue aging.

Lagging strand replication problem

The problem encountered at the 3' end of the lagging strand during DNA replication.

Role of telomeres in cancer

Telomeres can become critical in cancer as they allow for the unlimited division of cancer cells.

Telomere length and aging

As organisms age, telomeres typically shorten, which is associated with cellular aging and reduced regenerative capacity.

Telomerase activity in stem cells

Telomerase is often active in stem cells, enabling them to divide many times without losing telomere length.

Impact of lifestyle on telomere length

Factors such as stress, diet, and exercise can influence telomere length and cellular aging.

Methods to measure telomere length

Telomere length can be measured using techniques such as quantitative PCR and Southern blot analysis.

Telomere dysfunction

Telomere dysfunction can lead to genomic instability and is associated with various diseases, including cancer.