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.
Are telomeres short repeat sequences?
Telomeres are composed of
long stretches of tandem repeats of short sequence elements
, typically 5-8 bp long, which are rich in G residues on the strand oriented in the 5′ to 3′ direction toward the end of the chromosome.
What is the sequence of the DNA repeat in telomeres?
To prevent the loss of genes as chromosome ends wear down, the tips of eukaryotic chromosomes have specialized DNA “caps” called telomeres. Telomeres consist of hundreds or thousands of repeats of the same short DNA sequence, which varies between organisms but is
5′-TTAGGG-3′ in humans and other mammals
.
What is a telomere sequence?
Telomere, segment of DNA occurring at the ends of chromosomes in eukaryotic cells (cells containing a clearly defined nucleus). Telomeres are made up of repeated segments of DNA that consist of the sequence
5′-TTAGGG-3′
(in which T, A, and G are the bases thymine, adenine, and guanine, respectively).
Can telomere change sequence?
Mutation
of the template region in the RNA component of telomerase can cause incorporation of mutant DNA sequences at telomeres. … These results suggest that mutant telomere sequences elicit a checkpoint that is genetically distinct from those activated by deletion of telomerase or DNA damage.
What sequence is at the end of your telomeres?
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
.
What happens if telomeres are too long?
It was known that very short telomeres cause harm to a cell. But what was totally unexpected was our finding that damage also occurs when telomeres are very long.” … As telomeres shorten over time, the chromosomes themselves become vulnerable to damage.
Eventually the cells die
.
Can you lengthen your telomeres?
A small pilot study shows for the first time that
changes
in diet, exercise, stress management and social support may result in longer telomeres, the parts of chromosomes that affect aging. It is the first controlled trial to show that any intervention might lengthen telomeres over time.
How do you lengthen telomeres through diet?
Research shows that those with
higher levels of antioxidants such as Vitamin C, E and selenium
tend to have longer telomeres. Fruits and vegetables are the best sources of antioxidants, which is why a plant-based diet is highly recommended.
How do telomeres solve the end replication problem?
Eukaryotes have solved the end-replication problem by
locating highly repeated DNA sequence at the end, or telomeres, of each linear chromosome
. … In prokaryotes, the end-replication problem is solved by having circular DNA molecules as chromosomes. Another cause of telomere shortening is oxidative stress.
Can telomerase reverse aging?
An enzyme called
telomerase can slow, stop or perhaps even reverse the telomere shortening that happens as we age
. The amount of telomerase in our bodies declines as we age. Telomerase maintains and may even lengthen telomeres.
What is the best supplement for telomeres?
Vitamin D
promotes activity of telomerase, the repair enzyme that steadily adds to telomere length. Vitamins C and E preserve telomere length by reducing the chemical stresses that contribute to telomere shortening. Gamma-tocotrienol in particular may reverse telomere shortening and attendant cellular aging.
Why is it called satellite DNA?
The density of DNA is a function of its base and sequence, and
satellite DNA with its highly repetitive DNA has a reduced or a characteristic density compared to the rest of the genome
. Thus, the name ‘satellite DNA’ was coined.
What is telomere replication?
The ends of the linear chromosomes are known as telomeres:
repetitive sequences that code for no particular gene
. … Once the 3′ end of the lagging strand template is sufficiently elongated, DNA polymerase adds the complementary nucleotides to the ends of the chromosomes; thus, the ends of the chromosomes are replicated.
What is the end replication problem?
The end replication problem hypothesis
proposes that the ends of linear DNA cannot be replicated completely during lagging strand DNA synthesis
. Although the idea has been widely accepted for explaining telomere attrition during cell proliferation, it has never been directly demonstrated.
What is the function of telomerase?
Telomerase is the enzyme
responsible for maintenance of the length of telomeres by addition of guanine-rich repetitive sequences
. Telomerase activity is exhibited in gametes and stem and tumor cells.
