[Seatbelt]

Im really really confused about chromosomes.
[ so there are 23 pairs of chromosomes, 1 set of CHROMATIDS come from the mother (maternal chromosomes), the other set of CHROMATIDS come from the father (paternal chromosomes) in each cell in our body ] - is this right?

this adds up to the diploid number 46 chromatids? (confused, is chromatid and chromosome the same thing??)

so this must mean that there are 46 DNA molecules compacted into 46 chromatids (i came to this conclusion, can somebody tell me if this is right?) and each pair of homologous chromosomes are held together by a centromere?

[cuckoo99]

should answer your first question.


1 chromosome = 1 molecule of dna so you have 46 molecules of dna in each of your cells excluding sex cells.

a homologous pair of chromosomes are chromosome pairs of approximately the same length, centromere position, and staining pattern, with genes for the same characteristics at corresponding loci. One homologous chromosome is inherited from the organism's mother; the other from the organism's father. They are usually not identical.

[Seatbelt]

(Original post by cuckoo99)


should answer your first question.


1 chromosome = 1 molecule of dna so you have 46 molecules of dna in each of your cells excluding sex cells.

a homologous pair of chromosomes are chromosome pairs of approximately the same length, centromere position, and staining pattern, with genes for the same characteristics at corresponding loci. One homologous chromosome is inherited from the organism's mother; the other from the organism's father. They are usually not identical.

what do you mean by excluding sex cells?
i thought sex cells have a complete set of chromosomes, so 46 chromosomes/chromatids in each human sex cell?

[racheatworld]

(Original post by Seatbelt)
what do you mean by excluding sex cells?
i thought sex cells have a complete set of chromosomes, so 46 chromosomes/chromatids in each human sex cell?

Sex cells are haploid - they contain 23 chromosomes. This is because when a female sex cell (egg) and male sex cell (sperm) are combined during fertilisation, the cell produced will have 46 chromosomes - the full set.

If sex cells had 46 chromosomes and were not haploid, upon fertilisation a cell with 92 chromosomes would be produced.

[cuckoo99]

(Original post by Seatbelt)
what do you mean by excluding sex cells?
i thought sex cells have a complete set of chromosomes, so 46 chromosomes/chromatids in each human sex cell?

by your lack of knowledge of even the basic genetics i would strongly recommend going through this topic again from the start as mistaking sex cells for having 46 chromosomes is quite a big misconception. a gamete(sex cell) contains half the genetic information that normal cells do because it needs to fuse and create a zygote with another gamete of the opposite sex