If a human cell with 46 chromosomes divides by meiosis
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Meiosis is the cell division in the sex cells. The result of the process is four haploid daughter cells. In mens sperm and female eggs. Haploid means that it has just one set of the chromosomes – 23 chromosomes. Normal tissue cells includes 23 pairs of the chromosomes and are called diploid. Reproductive cells have to be haploid because the zygote is formed by two haploid cell - egg and sperm. Show
The Course of Meiosis[edit | edit source]Meiosis includes two nuclear divisions that takes place one after the other:
Meiosis is a type of a sexual reproduction. It is a base of the genetic diversity in offsprings. Meiosis has two parts – meiosis I and meiosis II. Each of them has 4 phases – prophase, metaphase, anaphase and telophase. Meiosis vs Mitosis[edit | edit source] The main differences is in the metaphase and the anaphase. During mitosis the chromosomes line up at the equatorial line. All of them lie just in one line. Then in the anaphase they are separate into the individual sister chromatids. The parent cell has 4N (92 chromosomes) and two daughter cells have 2n (46 chromosomes). Meiosis differs in that; during metaphase the chromosomes lie side by side. Then in the anaphase there is no division of the chromatid. The whole chromosome is pulled to the one pole of the cell. The parent cells have 4N (92 chromosomes) and the daughter cells have 2N (46 chromosomes). But that is just the first meiotic division. The second one takes place directly after - without replication of the DNA. It means that the daughter cell becomes "parent" and divides again. The result is a pair of the sex cell with 1N (23 chromosome). This we call the second meiotic division. The Disturbances of Meiosis[edit | edit source]The most important is the correct division of the chromosomes into the daughter cells. The mistake can occur in the first but also in the second meiotic division. It leads to the trisomy – an extra chromosome – or monosomy – missing a chromosome. We called it meiotic nondisjunction. The most famous disorder connecting with it is Down syndrome. Links[edit | edit source]Related articles[edit | edit source]
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Medical Genetics: How Chromosome Abnormalities HappenChromosomes are stick-shaped structures in the middle of each cell in the body. Each cell has 46 chromosomes grouped in 23 pairs. When a chromosome is abnormal, it can cause health problems in the body. Abnormal chromosomes most often happen as a result of an error during cell division. Chromosome abnormalities often happen due to one or more of these:
Errors during dividing of sex cells (meiosis)Meiosis (my-OH-sis) is the process in which sex cells divide and create new sex cells with half the number of chromosomes. Sperm and eggs are sex cells. Meiosis is the start of the process of how a baby grows. Normally, meiosis causes each parent to give 23 chromosomes to a pregnancy. When a sperm fertilizes an egg, the union leads to a baby with 46 chromosomes. But if meiosis doesn’t happen normally, a baby may have an extra chromosome (trisomy), or have a missing chromosome (monosomy). These problems can cause pregnancy loss. Or they can cause health problems in a child. A woman age 35 years or older is at higher risk of having a baby with a chromosomal abnormality. This is because errors in meiosis may be more likely to happen as a result of the aging process. Women are born with all of their eggs already in their ovaries. The eggs begin to mature during puberty. If a woman is 35 years old, the eggs in the ovaries are also 35 years old. You may be referred for genetic counseling or testing if you’re age 35 or older when you are pregnant. Men make new sperm ongoing. So age doesn’t increase the risk for chromosome abnormalities for older fathers a lot. But newer studies suggest that rare abnormalities do occur. Errors during dividing of other cells (mitosis)Mitosis (my-TOH-sis) is the dividing of all other cells in the body. It’s how a baby in the womb grows. Mitosis causes the number of chromosomes to double to 92, and then split in half back to 46. This process repeats constantly in the cells as the baby grows. Mitosis continues throughout your lifetime. It replaces skin cells, blood cells, and other types of cells that are damaged or naturally die. During pregnancy, an error in mitosis can occur. If the chromosomes don’t split into equal halves, the new cells can have an extra chromosome (47 total) or have a missing chromosome (45 total). Substances that cause birth defects (teratogens)A teratogen (ter-AT-uh-jen) is something that can cause or raise the risk for a birth defect in a baby. They are things that a mother may be exposed to during her pregnancy. Teratogens include:
Researchers have 2 ways of finding out if a substance is a teratogen:
When a cell with 46 chromosomes divides with mitotic cell division how many chromosomes will each resulting daughter cell have?At this point, nuclear division begins, and the parent cell is divided in half, forming 2 daughter cells. Each daughter cell will have half of the original 46 chromosomes, or 23 chromosomes. Each chromosome consists of 2 sister chromatids.
Does meiosis produce cells with 46 chromosomes?Therefore, meiosis results in four haploid genetically unique daughter cells, each with half the DNA of the parent cell (Figure below). In human cells, the parent cell has 46 chromosomes (23 pairs), so the cells produced by meiosis have 23 chromosomes.
What has 46 chromosomes mitosis or meiosis?When the cell divides, the copies are pulled apart, and each new cell gets one identical copy of each chromosome. This type of cell division is called mitosis, and it produces cells with a total of 46 chromosomes.
Are there 46 chromosomes after meiosis 1?Answer and Explanation: After meiosis I, a diploid parent cell that has 46 chromosomes will produce two daughter cells that are haploid and will only have 23 chromosomes. During meiosis I, the homologous chromosomes separate. After meiosis II, the daughter cells will still have 23 chromosomes each.
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