How many chromosomes are there in a human body cell?

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There are 46 chromosomes in a normal human body cell.

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Humans have diploid cells, meaning each one contains two copies of each chromosome. The number of unique chromosomes, including sex chromosomes, is 23 in humans. This is the n, or haploid number. 2n, or the diploid number is 46, and refers to the actual number of chromosomes in a human cell, including the duplicates.

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46 chromosomes.

ie, 23 pairs of which 22 pairs are autosomes and 1 pair of sex chromosomes.

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23 pairs of chromosomes, which results in 46 chromosomes.  22 of the pairs are automsomes, while 1 pair in the sex chromosomes (which XX results in a female and XY results in a male).

I would like to clarify that sometimes people can have more or less than 46 chromosomes is not due to mutation, but rather nondisjunction.  Basically it is caused by improper division of chromosomes during meiosis.  The only time someone can survive from nondisjunction (result in a vilable baby) is when the person has an extra chromosomes 21, or an extra sex chromosomes.  Also one may survive with only 1 X chromosome or missing part of chromosome 5.

Extra chromosome 21:  Down Syndrome

Missing a partial Chromosome 5:  Cri du chat Syndrome (aka Cat's Cry)

XXX:  Tripe X Syndrome 

X: Turner's Syndrome

XYY:  XYY Syndrome 

XXY:  Klinefelter's Syndrome

 

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There are 46 chromosomes that is 23 pairs of chromosomes that is 22 pair of autosomes and 1 pair of sex chromosomes.

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I have to correct the first answerer--the "normal" number of 46 chromosomes is the DIPLOID number, not the haploid. In egg and sperm cells, half the number is present, and this is known as the haploid number.

In some individuals, the diploid number is off; this is known as either a monosomy (only one of the usual pair is present), or a trisomy (3 copies, instead of two). The most well-known trisomy is Trisomy 21--3 copies of the 21st pair, otherwise known as Down Syndrome. This is not always obvious simply from counting chromosomes in a karyotype, as the extra material can be attached to another chromosome. Extra/missing X or Y chromosomes are other common genetic mistakes.

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