What is the difference between centrioles, centrosome, and the MTOC?
Organelles
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Centrioles are inside the centrosome, correct me if I'm wrong but -some means its membrane bound?
and a centrosome is an example of a MTOC
and a centrosome is an example of a MTOC
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Centrosomes and Centrioles. In many cells, microtubules grow out from a centrosome, a region often located near the nucleus that IS considered to be a "microtubule-organizing center." These microtubules function as compression-resisting girders of the cytoskeleton. Within the centrosome of an animal cell are a pair of centrioles, each composed of nine sets of triplet microtubules arranged in a ring (Figure 6,22). Before a cell divides, the centrioles replicate. Although centrioles may help organize microtubule assembly, they are not essential lor this function in all eukaryotes; centrosomes of most plants lack centrosomes, but have well-organized microtubules.
Bilology, 7th Ed, Campbell, Reece
I guess it's still considered an organelle, even though it does not have very explicit boundaries.
-some means a body, there is nothing in it implying that it will be membrane bound.
A centriole is a small organelle in the cytoplasm of animal cells. Located specifically within the centrosome "the microtubule organizing center"
Function: A centriole organizes the spindle apparatus during mitosis or meiosis
A centromere: area of a chromosome at which sister chromatids are joined. Function: point of attachment to the spindle fiber during meiosis and mitosis
Quick Recap:
So centrosomes and centrioles are related in function and organization of microtubules. And centromere is involved in joining of chromatids. I remember the relationship between centromere & chromatids by thinking of "CentroM for ChroM" Sorry, don't have better phrase.
Function: A centriole organizes the spindle apparatus during mitosis or meiosis
A centromere: area of a chromosome at which sister chromatids are joined. Function: point of attachment to the spindle fiber during meiosis and mitosis
Quick Recap:
So centrosomes and centrioles are related in function and organization of microtubules. And centromere is involved in joining of chromatids. I remember the relationship between centromere & chromatids by thinking of "CentroM for ChroM" Sorry, don't have better phrase.
so my EK FL #3 says that stabilizing microtubules would inhibit mitosis. Can you tell me why "stabilizing" the microtubules impede mitosis?
EK: "if the stability of microtubules is increased, then the microtubules cannot change length. this means the cell will not be able to elongate and dividine into two new daughter cells." This was a Discrete question
please quote me so i will see your response. i appreciate your help
EK: "if the stability of microtubules is increased, then the microtubules cannot change length. this means the cell will not be able to elongate and dividine into two new daughter cells." This was a Discrete question
please quote me so i will see your response. i appreciate your help
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microtubules need to change length rapidly for all kinds of different functions. They are useful for many jobs, structure and transport among them, and being able to quickly dismantle and re-appear somewhere else is one of their key features, iirc. And they "blow apart" pretty fast, once told to do so.
I can only imagine the chaos induced in a cell where they are suddenly stuck, rigid poles, unable to be moved. Isn't there a kind of anti-cancer agent that causes them to stick together (to kill the cell)? Let me see..
"Highly dynamic mitotic-spindle microtubules are among the most successful targets for anticancer therapy. Microtubule-targeted drugs, including paclitaxel and Vinca alkaloids, were previously considered to work primarily by increasing or decreasing the cellular microtubule mass. Although these effects might have a role in their chemotherapeutic actions, we now know that at lower concentrations, microtubule-targeted drugs can suppress microtubule dynamics without changing microtubule mass; this action leads to mitotic block and apoptosis."
http://www.nature.com/nrc/journal/v4/n4/full/nrc1317.html
also
http://jcs.biologists.org/content/122/15/2579.full
theres a bunch of info to read up on about microtubules. Two things I will never forget, I saw a picture in my molec/cell book once where they put a microtubule organizing center in the middle of a small box, and the organelle centered itself in the box by sending out microtubules to sense the shape of it's enclosure. The second thing is that apparently they divide when the cell does, and there is no way for the cell to makes it's own "new" organizing center from the DNA. Correct me if I am wrong, that is what I seem to recall.
centromere = point where the sister chromatids connect
centrioles = 2 circular/tube like things on the poles
MTOC = microtubules make the mitotic spindles that connect between the centrioles and centromeres, these help to guide the chromosomes to the opposite poles during anaphase
centrioles = 2 circular/tube like things on the poles
MTOC = microtubules make the mitotic spindles that connect between the centrioles and centromeres, these help to guide the chromosomes to the opposite poles during anaphase
