centrosome vs centriole

[GomerPyle]

I don't understand the difference. Centrosome is the site where microtubules originate from. So does the centrosome split into two centrioles, or how does it work?

Also, kinetechores are located on the chromosome itself, correct? And they originate from the centromere?

Then there is the telomere that is on the ends of chromosmes which serve to protect the DNA?

Thanks.

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[Synapsis]

I don't understand the difference. Centrosome is the site where microtubules originate from. So does the centrosome split into two centrioles, or how does it work?

Also, kinetechores are located on the chromosome itself, correct? And they originate from the centromere?

Then there is the telomere that is on the ends of chromosmes which serve to protect the DNA?

Thanks.

The centrosome contains the centrioles. The centrioles will duplicate during cell division. Now it turns out that centrosomes aren't necessary for mitosis. Plant cells lack centrosomes, and animal cells without centrosomes can be given functional spindles in vitro that work. It's thought that the centrosome makes mitosis more efficient. Just extra stuff that's not important.

Yep, kinetochores are on the chromosome at the centromere. Kinetochore microtubules are different than just the kinetochore. The kinetochore has motor proteins on it that bind the kinetochore microtubule.

And telomeres are at the end of the chromosome. With each round of replication the DNA strand can shorten slightly. Telomerase is an enzyme that maintains telomeres, stopping (or at least slowing) this process.

 

[gettheleadout]

The centrosome contains the centrioles. The centrioles will duplicate during cell division. Now it turns out that centrosomes aren't necessary for mitosis. Plant cells lack centrosomes, and animal cells without centrosomes can be given functional spindles in vitro that work. It's thought that the centrosome makes mitosis more efficient. Just extra stuff that's not important.

Yep, kinetochores are on the chromosome at the centromere. Kinetochore microtubules are different than just the kinetochore. The kinetochore has motor proteins on it that bind the kinetochore microtubule.

And telomeres are at the end of the chromosome. With each round of replication the DNA strand can shorten slightly. Telomerase is an enzyme that maintains telomeres, stopping (or at least slowing) this process.

You mean centrioles in all the bolded places.

 

[Synapsis]

You mean centrioles in all the bolded places.

Nope, I mean what I said. This was something my Cell Biology professor specifically spent a little more time on when discussing mitosis, and was a topic in a research paper he published, referenced here.

Now I have seen random sites that state that plant cells have centrosomes and no centrioles, but I think I'll go with what I was taught in upper level biology and what I've seen published, even though this may be just beyond the scope of the MCAT.

 

[gettheleadout]

Nope, I mean what I said. This was something my Cell Biology professor specifically spent a little more time on when discussing mitosis, and was a topic in a research paper he published, referenced here.

Now I have seen random sites that state that plant cells have centrosomes and no centrioles, but I think I'll go with what I was taught in upper level biology and what I've seen published, even though this may be just beyond the scope of the MCAT.

But it implies that centrioles are necessary for mitosis, which isn't true: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2883084/

 

[Synapsis]

But it implies that centrioles are necessary for mitosis, which isn't true: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2883084/

I didn't imply that, and neither did the paper I provided. I stated that the centrosome is not always necessary for mitosis, which in turn implies that the centriole is not always necessary for mitosis, which is correctly and explicitly stated multiple times in the paper you cited. The paper I provided merely implies that plant cells do not use centrioles or centrosomes, but they use CMTs. I offered this as evidence for why centrosomes are not critical for mitosis.

Cortical microtubules (CMTs) are essential for normal plant morphogenesis because they affect the axes of cell elongation and predict the placement of cell division planes. The function of the CMTs is intimately linked to their organizational state, which is subject to spatial and temporal modifications by developmental and environmental cues. CMT assembly dynamics govern when, where, and how microtubules appear in a cell's cortex, and the regulation of these properties affects their organization.

 

[gettheleadout]

I didn't imply that, and neither did the paper I provided. I stated that the centrosome is not always necessary for mitosis, which in turn implies that the centriole is not always necessary for mitosis, which is correctly and explicitly stated multiple times in the paper you cited. The paper I provided merely implies that plant cells do not use centrioles or centrosomes, but they use CMTs. I offered this as evidence for why centrosomes are not critical for mitosis.

I took your sentence regarding centrosomes improving efficiency to be distinguishing their effects relative to isolated centrioles, sorry. I wasn't referring to the Dixit paper.

 

[Gauss44]

From TBR: "The growth of microtubules occurs from regions called microtubule organizing centers (MTOCs). Three common centers are the centrosome (cell center), kinetochores (spindle attachment sites on chromosomes), and centrioles."

There's currently a good article about the centrisome cycle on wikipedia that helps to put this in context.

Me: The centrosome seems to be more of an area or collection of parts, two of those parts being centrioles. A centriole may or may not be able to migrate away from the centrosome.

 

[GomerPyle]

Okay wait, so the centrosome is in the middle of the cell and it contains the centrioles which duplicate during mitosis. The microtubules originate from the centrioles AND the kinetechores???

 

[sakabato93]

Okay wait, so the centrosome is in the middle of the cell and it contains the centrioles which duplicate during mitosis. The microtubules originate from the centrioles AND the kinetechores???

Centrosome is an organelle composed of orthogonal centrioles. The centrosome is an animal cell organelle that serves as the MTOC (microtubule organizing center). The microtubules originally form as asters that radiate from the MTOC. Some MTs will extend toward the metaphase plate where the chromosomes are aligned in order to attach to the kinetochores on chromosomes.

Centrosomes are NOT necessary for cell division. MTOC formation is sufficient for MT formation during cell division (but I'm not sure whether or not centrosomes are necessary for animal cell division under normal conditions).