In what part of the cell cycle does does DNA occur? How could you demostrate that in a labratory??
828091
Replication of DNA occurs in the "S" phase (or Synthesis phase) of the cell cycle process. Usually, people perform cell cycle analysis on cells fixed at progressively differing time points. In our laboratory, we fix our cells with 70% EtOH at 0, 12, 18, 24, and 48 hours. Then we use a FACS calibur machine to visualize and quantify the percentage of cells in each phase of the cell cycle.
248643
I'm not sure if you mean the "nucleus" or the "nucleolus", but either way, in cells which have a nucleus, the DNA resides here mostly because of seperation of activities in the cell - all of the enzymes used to process DNA (ie, winding and unwinding, transcription into RNA) are in the nucleus.  Other organelles in a cell, like the mitochondria or Golgi, similarly have membranes and components for specific cell activities.
285177
Mitosis\n\nThe beginning of mitosis is called prophase. In early prophase, the centrosomes move toward opposite poles of the cell, organizing the spindle microtubules between them. The sister chromatids become visible in the nucleus as they condense. \n\nIn late prophase, the nuclear membrane breaks down and some of the spindle microtubules attach to the sister chromatids. The microtubules pull the chromatid pairs to the midline of the cell, or metaphase plate.\n\n•••\n\nThe chromatids remain lined up between the poles of the cell during metaphase.\n\n•••\n\nAnaphase begins when the pairs of sister chromatids separate. The separated chromatids are now called chromosomes, and move toward the poles of the cell.\n\n•••\n\nThe chromosomes arrive at the poles in telophase, and new nuclear membranes form around them.\n\n•••\n\nDivision of the cytoplasmic components is called cytokinesis. \n\nIn animal cells, cytokinesis occurs when a ring of actin and myosin filaments constricts the plasma membrane at the equator. Eventually, the parent cell is divided into two cells.\n\nAnimal Cytokinesis Movie (500K)\n\n\n\nIn plant cells, a number of small vesicles fuse at the metaphase plate to form the cell plate. Over time, the cell plate reaches across the cell and joins with the plasma membrane.\n\n•••\n\nThe process of mitosis and cytokinesis creates two separate cells, each with an identical set of chromosomes. After cytokinesis, the daughter cells will enter interphase.
938356
Cells reproduce by cell division. This is called a-sexual reproduction or binary fission or Mitosis. This type of reproduction only requires one induvidual. The cell divides in order two create two daugter cells that are identical to the original cell. First Interphase, when the cell is making copies of DNA. In Prophase, the nucleolus fades and the chromatins condense into chromosomes. In Metaphase, all the chromosomes are aligned on spindle fibers. In Anaphase, the spindle fibers dissaspear. In Telophase, the daughter chromosomes move to the poles. In Cytokinesis, not truly part of Mitosis, there are now two finallized daughter cells.\n______________________\nHope this helps!!! :) :) \nHere's for more information:  http://www.cellsalive.com/mitosis.htm
113165
Mitosis occurs pretty much everywhere, the two major exceptions being red blood cells and nervous tissue. Aside from that name any living tissue in your body and there is mitosis occuring.
791273
Definitely b...\nDuring Interphase, there are 3 subphases - G1, S, and G2.  G1 is for growth of the cell, S is for synthesis of an extra set of chromosomes (amount of DNA in cells), and G2 is for preparation for the rest of cell division.  After interphase is prophase (nuclear membrane dissolves and DNA bundles up), then metaphase (DNA lines up on the center of the cell), anaphase (DNA separates towards poles), and telophase (Cell divides into two cells).  I hope this helps!\n\nAnswer: b. between the G1 and G2 phases of the cell cycle
893608
This is simple. The interphase is a stage of the cell cycle.\nHere is the article in Wikipedia:\n"Interphase is a phase of the cell cycle, defined only by the absence of cell division. During interphase, the cell obtains nutrients, and duplicates its chromosomes. Most eukaryotic cells spend most of their time in interphase. For example, human skin cells, which divide about once a day, spend roughly 22 hours in interphase. Cells during interphase may or may not be growing. At any given time, even in an area of rapid cell division such as the tip of a plant root, 90 percent of cells are in interphase. Some cells, such as nerve cells, can stay in interphase for decades. The cell grows and replicates its DNA and centrioles. There are 3 parts of interphase: G1 (growth 1 in which the cell creates organelles and begins metabolism), S phase (DNA synthesis in which the chromosomes of the cell are copied) and G2 (growth 2 in which the cell grows in preparation for cell division). Sometimes the cells exit the cell cycles (usually from G1 phase) and enter the G0 phase. In the G0 phase, cells are alive and metabolically active, but do not divide. In this phase cells do not copy their DNA and do not prepare for cell division. Many cells in the human body, including those in heart muscle, eyes, and brain are in the G0 phase. If these cells are damaged they cannot be replaced. Interphase is the step before the mitotic phase, though it is frequently erroneously thought to be part of mitosis. The mitotic phase follows interphase, and begins with prophase.\n\nDuring interphase, the chromosomes are found arranged in the nucleus and appear as a network of long, thin threads, called the chromatin. At some point before prophase begins, the chromosomes begin to replicate themselves to form pairs of identical chromosomes. The deoxyribose nucleic acid (DNA) of the chromosomes is in use only during interphase, when the cell is in a stable and self reliant phase. In prophase the two chromatids are still connected by something called the centromere. The sister chromosomes contract tightly. Meanwhile, the nucleolus and the nuclear envelope break down and disappear, since their components have been sufficiently altered. Outside the nucleus are two centrosomes which sprout microtubules by polymerizing free-floating proteins. The centrosomes push themselves to opposite ends of the cell. The network of microtubules forms the beginning of the mitotic spindle. These spindle fibers become visible. The centrioles separate starting to radiate bundles of fibers, called asters. The spindle fibers run from one centriole to the other, at both poles of the cell. At the onset of prophase, chromatin condenses together into a highly ordered structure called a chromosome."\n---- End of citation ---\n\n\nRegarding the staining of the onion specimen - you do this in order to see the inner parts of the cell at the microscope. There are diferent types of colorations and you use one or other dependeg on what do you want to see (for example some coloration could be used for seing the chromosomes, while other coloration might be better for examining the cell wall).
612256
Those portions of DNA are probably difficult to replicate properly (or perfectly I should say).  What's the difference between 5,000 repeats and 4,995?  Not much as far as the cell is concerned.
283484
ur question should be under biology but still, mitosis is the process of when the cells split to create 4 indentical cells during mitosis, one copy of the dna is distributed into each of the tow daughter cells mitosis id divided into 4 interphases: prophase, metaphase, anaphase, and telophase. in prophase, the chromatin in the nucleus condenses to form chorosomes. structures celled spindle fibers form a bridge between the ends of the cell. the nuclear membrane breaks down. in metaphase, the chromosomes line up across the center of the cell. each chromosome attaches to a spindle fiber at its centromere, which still holds the chromatids together. in anaphase, the centromeres split. the two chromatids separate. one chromatid moves along the spindle fiber to one end of the cell. the other chromatid moves to the opposite end. the cell becomes stretched out as the opposite ends pull apart. in telophase, the chromosomes begin to stretch out and lose their rodlike appearance. this occurs in the two regions at the ends of the cell. a new nuclear membrane forms around each region of chromosomes. o yeah and btw mitosis is on stage of the cell cycle there are like 2 before it and 1 after it
918391
When cells prepare for mitosis their DNA strands twist together more and shorten enough to be seen under a microscope.  During normal interphase the DNA is unraveled and working, so the strands appear longer and thinner.  Most microscope cannot allow you to see these thin strands.
396880
DNA duplicates during inter phase of cell division to prepare the cell for mitosis
417992
The replication of chromosomes does not occur during mitosis. This replication occurs during the S phase of the interphase. Think of the word SYNTHESIS when you think of the S phase. The new strands of DNA in the chromosome are SYNTHESIZED in the S phase.
848818
If your organism has a nucleus, it occurs in the nucleus, if not it happens in the cytosol of the cell, not in an organelle.
44364
The cell cycle, or cell division cycle, is the cycle of events in a eukaryotic cell from one cell division to the next. It consists of interphase, mitosis, and usually cell division. The cell cycle is regulated by cyclins and cyclin-dependent kinases. Leland H. Hartwell, R. Timothy Hunt, and Paul M. Nurse won the 2001 Nobel Prize in Physiology or Medicine for their discovery of these central molecules in the regulation of the cell cycle.\nThe phases of the cell cycle are:\n\nThe G0 phase is a period in the cell cycle where cells exist in a quiescent state. \nThe G1 phase is the first growth phase. \nS phase, during which the DNA is replicated, where S stands for the Synthesis of DNA. \nG2 phase is the second growth phase, also the preparation phase for the cell. \nM phase or mitosis and cytokinesis, the actual division of the cell into two daughter cells. \nA surveillance system, so-called "checkpoints", monitor the cell for DNA damage and failure to perform critical processes. Checkpoints can block progression through the phases of the cell cycle if certain conditions are not met. For instance, there is a checkpoint which monitors DNA replication and keeps cells from proceeding to mitosis before DNA replication is completed. Similarly, the spindle checkpoint blocks the transition from metaphase to anaphase within mitosis if not all chromosomes are attached to the mitotic spindle.\n\nIf this system senses a problem, a network of signaling molecules instructs the cell to stop dividing. They can let the cell know whether to repair the damage or initiate programmed cell death, a form of which is called apoptosis. Programmed cell death ensures that the damaged cell is not further propagated. For example, a certain protein, called p53, acts to accept signals provoked by DNA damage. It responds by stimulating the production of inhibitory proteins that then halt the DNA replication process. Without proper p53 function, DNA damage can accumulate unchecked. A direct consequence is that the damaged gene progresses into a cancerous state. Today, defects in p53 are associated with a variety of cancers, including some breast and colon cancers.\n\nSome cells, such as neurons, never divide once they become locked in a G0 phase. However, recent data has shown that neurons undergoing cell death re-enter the cell cycle. Addition of cell cycle inhibitors prevent this type cell death called apoptosis.
68378
I think what you're looking for has to do with replication. Every time the cell goes through mitosis to divide, it has to make an exact copy of all the DNA in the cell, so that there are two complete copies, one for each daughter cell. The process of replication and division is the cell cycle.\n\nIn replication, a complex of enzymes copies the DNA by unzipping the double helix to expose the single strands. Someone else mentioned A-T C-G bair pairing and that is correct. The four subunits in DNA are the bases, and they are abbreviated A,T,C and G. Just by the shape of the molecules, A will connect with T and C with G pretty much always (though there are exceptions that are beyond the scope of a general explanation). \n\nSo in replication, enzymes pull the two strands of the double helix apart in short regions, pulling apart the A-T C-G bair pairing. It is energetically unfavorable to have a single strand of DNA exposed and not base paired. Free nucleotides in the cell will come in and form hydrogen bonds with the exposed template strand (it will happen on both strands), and then enzymes will connect the newly deposited bases with phosphodiester linkages to form a new DNA molecule. This forms a new strand of what is called duplex DNA, meaning it is a new double helix. The complementarity of the base pairs drives replication to produce an exact copy of each part of the genetic code. The error rate is very low, but errors can and do occur, and there is proofreading machinery to check for mistakes and excise and replace incorrect base pairs.\n\nPictures are helpful...in the second link, scroll down to see the replication bubble. A replication fork and a replication bubble are essentially the same thing...it's the site where the double helix is open and replication is occurring.
891283
Chromatin is the unbound DNA inside the nucleus.  So its pretty much what form the DNA is in at any time thats not cell division.
792899
mitosis is the normal mode of cell multiplication and increasing there number without a change in their constiution so it occurs in all the SOMATIC CELLS (normal cells of body not involved in sexual reproduction).\nmeiosis occur in gamete forming cells as it is the reductoinal division