Update enter image description here

This is for a diploid cell (2n).

At G1, cell growth before the DNA is duplicated.

At S, DNA replicated. Chromosomes doubled!

At G2, cell growth

Then Mitosis; Prophase, Metaphase, Anaphase, Telophase, Cytokinesis

Could anyone explain if the chart is correct or incorrect?

  • 1
    $\begingroup$ Closevoters: please read the actual text of the close reason. The OP here has clearly shown their attempt at an answer. $\endgroup$
    – terdon
    Jan 20, 2017 at 10:34
  • 1
    $\begingroup$ I agree with @terdon, this might be not the greatest question but there is no reason to close it. $\endgroup$
    – Chris
    Jan 20, 2017 at 12:21
  • $\begingroup$ can you explain what mlcl means? $\endgroup$
    – KingBoomie
    Jan 21, 2017 at 18:12
  • $\begingroup$ Further one chromosome does not contain the whole genome just a chuck of it (however sometimes a whole genome can be on one chromsoome in the case of simple life forms such as bacteria) can you please specify the organism you are talking about? $\endgroup$
    – KingBoomie
    Jan 21, 2017 at 18:18
  • $\begingroup$ Mlcl= Molecule. and idk what organism is. It wasnt specify. Initial chromosome number was 6 (which i believe 2n=6). $\endgroup$
    – Chris
    Jan 21, 2017 at 21:20

1 Answer 1


# DNA molecules
A chromosome can have either 1 DNA molecule or 2, this depends upon what stage the cell is at that moment. It actually might help to know what chromatids are:

A chromatid (Greek khrōmat- 'color' + -id) is one copy of a newly copied chromosome which is still joined to the original copy by a single centromere. (wiki)

This means that the number of chromatids is directly related to the number of DNA molecuels.

Before replication, one chromosome is composed of one DNA molecule. Following replication, each chromosome is composed of two DNA molecules; in other words, DNA replication itself increases the amount of DNA but does not increase the number of chromosomes.(wiki)

enter image description here
We can now add another row which indicates the DNA molecules, chromatids are directly related to the number of DNA molecules thus from left to right:

 46        92         92        46

These are the basics, now in some more detail about mitosis:
enter image description here So based on the number of chromatids and your chromosome number you can figure out the nubmer of chormatids and thus the number of DNA molecules:
Thus before replication (G1) = 6, then after S phase (G2) = 12, then metaphase = 12 and after cytokinesis = 6. Just as in your table so that part is correct!

# of chromosomes
You can read these from the table, however I think it's important to understand what is happening. In simple words chromatids and chromosomes are related in this sense:

It is only when sister chromatids separate – a step signaling that anaphase has begun – that each chromatid is considered a separate, individual chromosome (source)

The phase in which the chromatids seperate is called anaphase, so after this seperation:
enter image description here
we consider the previoulsy chromatids as chromosomes. Thus anaphase and telophase contain the double number of chromosomes as the amount you started with. However anaphase and telophase are not mentioned in your table. So let's go back to the phases in your table. During metphase the chromatids are still connected to each other, meaning that we consider them as one chromosome (the same is true for G1 and G2, because we did not seperate anything). So that part of you table is correct too.

# genome copies

The human genome is the complete set of nucleic acid sequence for humans (Homo sapiens), encoded as DNA within the 23 chromosome pairs in cell nuclei and in a small DNA molecule found within individual mitochondria.(wiki)

However read this question and the answers, some say 1 genome per cell and some say two genomes per cell, this confuses me too so I'm not sure about this one, however based on the wiki it would say that 2n = one genome, which would make sense because the two pair of chromosomes are not equal and when saying you have two genomes per cell you are actually counting mitochondrial DNA twice.

  • 1
    $\begingroup$ I think the number of genome copies is correct on my chart. What do you think? $\endgroup$
    – Chris
    Jan 24, 2017 at 0:04
  • $\begingroup$ I think it is @Chris $\endgroup$
    – KingBoomie
    Jan 24, 2017 at 14:44

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .