Many cancer cells are immortal and can be cultured in the...

Name: Problem 13, Chapter 12: Biology
Uploaded: 2021-08-05T05:20:18-08:00
Duration: 3 min 44 s
Channel: Bryan Valdivia
Description: Many cancer cells are immortal and can be cultured in the laboratory for many years. Many of these cell lines have highly active telomerase activities. Why would that affect the ability of cancer cells to sustain growth and cell division?

Many cancer cells are immortal and can be cultured in the laboratory for many years. Many of these cell lines have highly active telomerase activities. Why would that affect the ability of cancer cells to sustain growth and cell division?

Key Concepts

Telomeres

Telomeres are protective caps at the end of chromosomes composed of repetitive DNA sequences and proteins. They prevent the loss of essential genetic information during DNA replication and protect chromosome ends from degradation and unwanted repair. Without proper maintenance, telomeres shorten with each cell division, eventually leading to cell cycle arrest or apoptosis.

Telomerase

Telomerase is an enzyme that adds repetitive nucleotide sequences to the ends of telomeres. This maintenance mechanism compensates for the natural shortening of telomeres during cell division, enabling cells to bypass the normal limit on divisions. In many cancer cells, high telomerase activity allows them to maintain telomere length, contributing to their ability to proliferate indefinitely.

Cell Immortality

Cell immortality refers to the ability of cells to bypass the normal limit on cell divisions, leading to continuous growth and proliferation. This trait is commonly observed in cancer cells and is often facilitated by the reactivation of telomerase, which prevents the onset of replicative senescence by stabilizing telomere length.

Transcript

00:01 Okay, alright to answer this question, let's talk about telomers.

00:03 Remember that we have like our genomes, it's a range, our genome is arranged in chromosomes.

00:10 Okay, we have a total of 46 chromosomes, allenged in pairs.

00:18 It means we're going to have 23 pairs of chromosomes.

00:21 For example, this is going to be a chromosome, okay? it's going to be a chromosome.

00:27 It can be chromosome number one, two, three, or whatever of these chromosomes.

00:31 Chromosomes or like these parts of the chromosomes these regions at the end of chromosomes are going to be called telomers okay they are going to have many like a dna sequence here but there is one implication here that when the cell does cell division cell division okay the telomers telomers are going to shorten are going to become like shorter okay because it is like one part is going to be called consumed so this part is going to be consumed and it is going to be like the telomers are going to become shorter okay so the length of the telomers is going to practically tell us how long this cell is going to keep dividing okay it means once that the these telomers will use up to this point think it means this cell cannot divide further or can divide anymore okay so in order to maintain like or to prolong the number of cell divisions that our cells can do, where we have an enzyme called telomerase, okay? and after a cell division, what telomerate, well, what telomerases, i'm sorry, are going to do, it is that they are going to, these telomeres are going to add dna to the telomeres.

02:08 So for example, let's suppose this is a normal length of the telomers like this.

02:14 Okay, and after a cell division, one of this is consumed and you have only this.

02:23 But telomerase is what i are going to do.

02:25 They are going to build dna here in the telomers...

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