What is the telomere repeat sequence in humans?
Telomeres are sections of DNA? found at the ends of each of our chromosomes?. They consist of the same sequence of bases ?repeated over and over. In humans the telomere sequence is TTAGGG. This sequence is usually repeated about 3,000 times and can reach up to 15,000 base pairs? in length.
Where is telomerase most active?
Telomerase is not usually active in most somatic cells (cells of the body), but it’s active in germ cells (the cells that make sperm and eggs) and some adult stem cells.
What is the point of telomerase?
In egg and sperm cells, an enzyme called telomerase keeps adding more of the repeating sequence onto the end of DNA strands, so that the telomeres in these cells don’t shorten. In other cells, telomerase is less active, leading to the gradual shortening of telomeres over time.
What enzyme is responsible for maintaining the length of telomeres?
Are telomeres non coding?
Telomeres are made of repetitive sequences of non-coding DNA that protect the chromosome from damage. Each time a cell divides, the telomeres become shorter. Eventually, the telomeres become so short that the cell can no longer divide.
How do cancer cells use telomerase?
Cancer cells achieve proliferative immortality by activating or upregulating the normally silent human TERT gene (hTERT) that encodes telomerase, a protein with reverse transcriptase activity that complexes with other proteins and a functional RNA (encoded by hTR, also called hTERC) to make a ribonucleoprotein enzyme …
What are 90% of human cancers due to?
The fact that only 5–10% of all cancer cases are due to genetic defects and that the remaining 90–95% are due to environment and lifestyle provides major opportunities for preventing cancer.
How do you make cancer cells die?
But cancer cells also die from withdrawal of a hormone such as estrogen or androgen, blockade of a growth factor such as EGFR, loss of cellular attachment, interference with intracellular signaling, amino acid starvation, viral infection, and immune activation.