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It is possible to count chromosomes only during vell division (mitosis or meiosis). This is because when the cell is not dividing the chromosomes are in an uncoiled, extended state and are not visible under the microscope. During cell division the chromosomes coil up, becoming shorter and thicker and so visible. At this time they can be counted.
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Why is DNA spread out during interphase?
So transcription factors and RNA polymerase have access to it to induce transcription. DNA that is not transcribed in a particular cell (e.g. hemoglobin gene in nerve cells) is not unraveled as much and remains as tightly packed heterochromatin. The parts of your DNA that are actively transcribed unravel the most and are called euchromatin.
Why cant sex cells form by mitosis?
if I'm not mistaken I'm pretty sure its that sperm cells and the egg. (gamete's)each have around 23 chromosomes each. and a skin cell already has 46 chromosomes.so mitosis wouldn't be able to happen.well at least that's what i think.
Are homologous chromosomes present in prokaryotic cells?
NO,in place of histone protien prolamin is present which act as histone analog in prokaryotes.
What is formed during mitosis?
Mitosis creates TWO new cells, which are used for growth and repair. Each of these new cells has the same number of chromosomes as the parent cell, 46 and it happens to reproduce and replace damaged cells and to allow an organism to grow. Im doing the science gcse exam with it in today so i need to know it :D
Why do you need to use oceto orcein in mitosis?
Oceto orcein is a stain commonly used in mitosis studies because it helps to visualize chromosomal structures. Specifically, it stains chromosomes, highlighting their shape, size, and number, making it easier to observe and analyze mitotic division. It enhances contrast and allows for better identification and characterization of various stages of mitosis.
What do chromosomes do before mitosis?
Before mitosis begins, the chromosomes in a cell replicate. This occurs during the S (synthesis) phase. Chromosomes need to replicate so that when the cell divides at the end of mitosis, the daughter cells each recieve a copy of the chromosomes.
Why do cells need to double their chromosomes before mitosis starts?
They are in need of reproduction.
What is happening when chromosomes attach to spindle fibers?
That would be during metaphase in mitosis and the chromosomes attach to the spindle fibers because each half of the chromosomes need to migrate to the opposite poles. The spindle fibers are temporary but aid in the movement of the chromosomes.
When random assortment of chromosomes IN MITOSIS?
Crossing over occurs in meiosis. There is no need for crossing over in mitosis.
How many chromosomes are there in each daughter cell after mitosis?
There are 46 chromosomes or 23 pairs of chromosomes in each daughter cell after mitosis. Each daughter cells need 46 or 23 pairs of chromosomes to work properly and survive.
Why do chromosomes line up in the middle of the cell during metaphase?
It is important that chromosomes move during mitosis because the chromosomes' sister chromatids need to separate. They must separate to become daughter cell-carrying chromosomes themselves.
Why is it important that sex cells do not go through mitosis?
sex cells need to go through meiosis because the daughter cells will get half the chromosomes. if they when through mitosis they would get all the necessary chromosomes and when an egg is fertilized and creates a child it will have double the number of chromosomes that it needs. it could cause mutations.
Why do cells need to go through division?
Mitosis is how somatic-or non-reproductive cells-divide. ... In mitosis, the important thing to remember is that the daughter cells each have the same chromosomes and DNA as the parent cell. The daughter cells from mitosis are called diploid cells. Diploid cells have two complete sets of chromosomes.
Why is DNA spread out during interphase?
So transcription factors and RNA polymerase have access to it to induce transcription. DNA that is not transcribed in a particular cell (e.g. hemoglobin gene in nerve cells) is not unraveled as much and remains as tightly packed heterochromatin. The parts of your DNA that are actively transcribed unravel the most and are called euchromatin.
How do you describe each phase of mitosis?
Soon before interphase ends, the chromosomes duplicate. During prophase, the chromosomes line up in their pairs. Metaphase has the chromosomes centering to be split, while anaphase splits the chromosomes apart. Telophase forms the new nuclei, and finally divides the cell into two.
How does the structure of a eukaryotic chromosome during mitosis differ from its structure during the rest of the cell cycle?
During cell division, chromosomes are condensed. They coil and supercoil, becoming thousands of times shorter and much fatter, so that they are visible under a light microscope.Being condensed, the chromosomes move freely through the cell during metaphase and anaphase without tangling.Much of prophase is taken up with this condensation, and much of telophase with its opposite: extension.During interphase, chromosomes need to expose sequences of nucleotides as templates for nucleic acid synthesis (transcription and replication). The chromosomes therefore have to be fully uncoiled (extended).
Why do mitosis and mitosis need to occur?
Mitosis is used for several purposes 1. Growth. the embryo increases in size due to mitosis. Enlargement of the embryo, young child and growth during puberty is due in part to increasing the number of cells. 2. Repair. If you cut yourself, or an incision is made during surgery, the hole is closed by cells dividing to close the space created by the wound. 3. Replacement. Some cells wear out rapidly (blood - 90-120 days; skin - 2 weeks; intestine 2.5 days) these old and worn out cells need to be replaced on a constant basis 4. Reproduction - protists that undergo mitosis have produced two identical cells and thus have reproduced 5. Cancer - unfortunately cancer is mitosis of cells that we don't want to be undergoing mitosis. Meiosis is used to produce the sperm and the egg each of which have half the number of chromosomes as the starting cell. This is so that when a sperm fertilizes an egg the total number of chromosomes is equal to that in any other cell
