Quick Answer: Why Is Telomerase Necessary For Complete Replication Of A Chromosome?

What is telomerase and why is it important?

The enzyme telomerase adds TTAGGG repeats onto mammalian telomeres, which prevents their shortening.

The activation of telomerase in malignant cancers seems to be an important step in tumorigenesis, whereby the cell gains the ability of indefinite proliferation to become immortal..

Why are telomeres necessary?

Their job is to stop the ends of chromosomes from fraying or sticking to each other, much like the plastic tips on the ends of shoelaces. Telomeres also play an important role in making sure our DNA gets copied properly when cells divide. … DNA strands get shorter and shorter with every cell division.

Why do bacteria not need telomerase?

Bacteria do not have the end-replication problem, because its DNA is circular. In eukaryotes, the chromosome ends are called telomeres which have at least two functions: to protect chromosomes from fusing with each other.

What does telomerase mean?

: a DNA polymerase that is a ribonucleoprotein catalyzing the elongation of chromosomal telomeres in eukaryotic cell division and is particularly active in cancer cells.

What happens if telomerase is blocked?

However, blocking telomerase activity could affect cells where telomerase activity is important, such as sperm, eggs, platelets and immune cells. Disrupting telomerase in these cell types could affect fertility, wound healing and the ability to fight infections.

How does telomerase cause cancer?

It is believed that cancer occurs because a genetic mutation can trigger the production of an enzyme, known as telomerase, which prevents telomeres from shortening. While every cell in the body has the genetic coding to produce telomerase, only certain cells actually need it.

How many Telomeres are in a chromosome?

2 telomeresThere are 2 telomeres in each chromosome which is equal to 92 telomeres in total including all 46 chromosomes.

What enzyme covalently connects segments of DNA?

AP Bio – Chapters 16 & 17ABuntwists and separates the template DNA strands at the replication forkhelicaseCatalyzes synthesis of a new strand of DNADNA polymeraseCovalently connects short segments of DNAligaseSynthesizes short segments of RNAprimase43 more rows

Does Ecoli have telomeres?

Each eukaryotic chromosome consists of a single molecule of DNA associated with a variety of proteins. (This is in contrast to such bacterial chromosomes as that in E. … coli that is a closed circle, i.e. has no ends.)

Why is telomerase necessary during the replication of eukaryotic chromosomes?

To prevent the loss of genes as chromosome ends wear down, the tips of eukaryotic chromosomes have specialized DNA “caps” called telomeres. … Proteins associated with the telomere ends also help protect them and prevent them from triggering DNA repair pathways.

Is telomerase good or bad?

Too much telomerase can help confer immortality onto cancer cells and actually increase the likelihood of cancer, whereas too little telomerase can also increase cancer by depleting the healthy regenerative potential of the body.

What foods lengthen telomeres?

Telomere length is positively associated with the consumption of legumes, nuts, seaweed, fruits, and 100% fruit juice, dairy products, and coffee, whereas it is inversely associated with consumption of alcohol, red meat, or processed meat [27,28,33,34].

Why are telomeres a necessary component of linear chromosomes?

Why are telomeres a necessary component of linear chromosomes? … They maintain the length of a chromosome because DNA is shortened every time it is replicated.

What is the role of telomerase in DNA replication?

The ends of the linear chromosomes are known as telomeres: repetitive sequences that code for no particular gene. These telomeres protect the important genes from being deleted as cells divide and as DNA strands shorten during replication. … Telomerase adds complementary RNA bases to the 3′ end of the DNA strand.

How does telomerase solve the end replication problem?

The mechanism for restoring the ends of DNA molecule in a chromosome relies on telomerase. This enzyme works by adding tandem repeats of a simple sequence to the 3′ end of a DNA strand. Hence, the loss of genomic sequences at each replication cycle can be compensated by addition of DNA sequence repeats.

What is the role of telomerase in cancer?

Telomeres, repetitive (TTAGGG) DNA–protein complexes at the ends of chromosomes, are crucial for the survival of cancer cells. They are maintained by an enzyme called telomerase in the vast majority of tumors. … Telomeres protect chromosome ends from fusion and from being recognized as sites of DNA damage (Box 1).

Where is telomerase found?

Telomerase is found in fetal tissues, adult germ cells, and also tumor cells. Telomerase activity is regulated during development and has a very low, almost undetectable activity in somatic (body) cells. Because these somatic cells do not regularly use telomerase, they age. The result of aging cells is an aging body.

Do bacteria have chromosomes?

The DNA of most bacteria is contained in a single circular molecule, called the bacterial chromosome. The chromosome, along with several proteins and RNA molecules, forms an irregularly shaped structure called the nucleoid. This sits in the cytoplasm of the bacterial cell.