A chromatid is one of the two strands that form when a chromosome replicates itself for the process of cell division (either mitosis or meiosis). Prior to replication, human somatic cells contain 46 chromosomes. Thus, after replication, there would be 92 chromatids.
In other words, a chromatid is one half of a replicated chromosome. Two chromatids are joined together by a central centromere to form one single chromosome. The two chromatids that are joined by a centromere are sometimes referred to as “sister chromatids.” Chromatids remain as long as they are attached to the centromere. Thus, chromatids are present during prophase and metaphase of mitosis.
Once a chromatid becomes detached from the centromere, it becomes a chromosome. Thus, it is during anaphase of mitosis that the separation of sister chromatids occurs.
Further Reading
How many chromosomes are there in a human body cell?
There are 46 chromosomes in a normal human body cell.
How many chromosomes are there in a human body cell?
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.
How many chromosomes are there in a human body cell?
46 chromosomes.
ie, 23 pairs of which 22 pairs are autosomes and 1 pair of sex chromosomes.
How many chromosomes are there in a human body cell?
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
How many chromosomes are there in a human body cell?
There are 46 chromosomes that is 23 pairs of chromosomes that is 22 pair of autosomes and 1 pair of sex chromosomes.
How many chromosomes are there in a human body cell?
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.
How many of each kind of chromosome does a body cell have?
Most human cells are called somatic cells, meaning they are not cells produced for sexual reproduction. Somatic cells in humans are diploid, meaning they have two copies of each human chromosome. There are 23 pairs of human chromosomes (22 autosome pairs and 1 pair of sex chromosomes) for a total of 46 chromosomes. The one exception here are gametes, or sperm or egg cells created for sexual reproduction. These cells are haploid, meaning they have only one of each chromosome for a total of 23 chromosomes. This is so that when a sperm and egg cell combine to form a zygote during fertilization, they produce a diploid cell with 46 chromosomes.
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