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7

In many cases cell division depends on the stage of development an organism is in. The rate of cell division is obviously much faster in a developing organism and from what I understand fully differentiated cells such as neuron and those in skeletal muscles don't divide (correct me if I'm wrong here). In early development totipotent cells (stem cells that ...


6

If the question is about the one and only most important difference between mitosis and meiosis, then the answer "meiosis reduces ploidy" is probably correct. But if the list of important differences is open, it would be critical to add that mitosis generates identical cells (identical to each other and any ancestral cells, barring rare new mutations), while ...


6

Mature, differentiated neurons do not divide (undergo mitosis), but apparently there is a small population of self-renewing neural stem cells in adults that can produce new neurons. Neurogenesis predominantly occurs in the subventricular and subgranular zones of the brain. Peripheral nerves can regenerate along its axon as long as the endoneurial tube and ...


5

I'm actually not sure myself. If I were to use something, I would go with "Mitos'd" and "Meios'd". However, you may not win over many fans, depending on the audience. If it's with students or maybe a professor, you could get away with shortening the processes. If it's in any formal setting, be as precise and descriptive as possible. It's not a lot of ...


4

Telomeres do not "cause" ageing as such - although you are right that they limit the number of times a somatic cell can divide. Each time a cell divides the chromosomes are replicated in an imperfect way, and as such a small amount of DNA is lost from the end of the chromosome during each round of cell division. Telomeres are just extensions to the ...


3

Errors in division occur all the time and can show up in any dividing cell; this is, of course, important for cancer biology. If one of my cells replicates oddly right now it likely won't matter since it's only one out of trillions, but if that happened at a very early age in development it could be present in many if not all of my cells. Identical twins ...


3

well i had done some search on this before but not for CHO (I checked for the cells that I was culturing). i can look up for more. Just pasting the data that I have right now. Cell type Total G1 S G2 M S+G2/G1 Ref Neuro2a 9 2 5 1.5 0.5 3.25 De Laat et al 1980 PNAS Hela 16.2 7.7 7.2 ...


2

According to all I've learned and heard, the only thing consistent about meiosis is that it reduces ploidy because homologous chromosomes are separated. (Not necessarily diploid to haploid - it can be polyploid as well, although odd ploidies usually seem to mess it up.) Mitosis on the other hand mainly serves to separate two copies of a genome into ...


2

Question is two years old, and the answer is approx 20 yo, but I believe both are still pertinent: According to Jared Diamond on pg 12 of his Harper paper version (1993 -- but reissued in 2006) of The Third Chimpanzee, we replace intestinal lining epithelium every few days, urinary bladder lining every two months, and replace every red blood cell about every ...


2

It's a spatial constraint. As the DNA is replicated, the two resulting chromatids are kept stuck together by cohesin proteins. The DNA sequence that corresponds to the centromere then coalesces the kinetochore. It seems that the DNA-protein interactions at the centromeres creates a particular structure along the chromosome. Since the two chromatids have ...


2

Identical twins do start out identical, but their DNA will quickly diverge. Not in a dramatic way, but in point mutations, at random locations, in different cells. Think of how there is a certain error rate associated with DNA replication - so even from that very first cell, when it divides to form a second cell, there is a chance there may be mutations in ...


2

Cytokinesis is separate from mitosis. What edition are you looking at? To quote from the Fourth Edition: The cell cycle culminates in the division of the cytoplasm by cytokinesis. In a typical cell, cytokinesis accompanies every mitosis, although some cells, such as Drosophila embryos (discussed later) and vertebrate osteoclasts (discussed in Chapter ...


2

If you are thinking of a process like meiosis but followed by DNA duplication, the problem is that this would create daughter cells that do not have the same genome as the parent cell. The diploid genome of a sexually reproducing species' cell has different alleles of the same locus. If the cell replicates itself by passing one chromatid to each daughter ...


2

Colchicine inhibits the formation of the microtubules by binding to tubilin and rendering it unavailable for the polymerization. Thats why the cells get arrested in the metaphase and can not go on further in the cell cycle and divide. For chromosome studies this is very useful since this is the phase where the chromatin is most condensed and can be viewed ...


2

There are many questions in your question. I'll try to answer each question pointwise. Which flags are used by the enzymes in the process of making the centromere to tell them that it is the right spot There are some centromere associated repeats in the DNA which mark the site for centromere assembly. There is no particular consensus sequence of this ...


1

Couldn't fit in a comment... To me, your question sounds like "what are the possible advantages of sexual reproduction over asexual reproduction?" but in the meantime you're saying that you're not interested neither in the advantage of recombination nor in the advantage of "independent assortment". I don't quite see what you mean by "independent assortment" ...


1

The biggest problem is this: if you have only one copy of the DNA how is it going to divide it between the two cells so that both have a complete copy?


1

The number of spindle fibres is actually more than total number of kinetochore pairs. The fibres attached to kinetochores are called K-fibres and the others are called polar fibres. I cant surely say that there is exactly one K-fibre per kinetochore but as per its definition and from the microscopic images you can conclude that there is one per kinetochore. ...


1

I'm not sure about the first developmental stages but, given you already have hundreds of cells with slightly different physiology, the next developmental stages like dev. of neural tube happen through excretion of translation factors and growth factors in several cells. Each of those cells that are in a region where more than one excretion overlaps get a ...


1

As was pointed out by @jello differentiated neurons do not divide, instead new neurons are recruited into existing networks from undifferentiated cells. This process is called neurogenesis. A high level summary of adult neurogenesis: Neural progenitor cells differentiate into new neurons that have zero (or very few) synaptic connections, but are sensitive ...



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