I'm trying to understanding base pairing. So every linear chromosome is a double stranded double helix. Is this double stranded property the same as saying an organism is diploid? Or do the chromosomes of a haploid eukaryotic organism, like a member of Fungi, each have 2 strands (with the purines always pairing w/ pyrimidines), which would imply that diploids organisms actually have 4 strands?

EDIT: Part of my confusion comes from the fact that in diploid organisms, each parent gives 1 chromosome to the child. If the double stranded property is the same as saying an organism is diploid, does this mean that say if a nucleotide on one chromosome is A, then the nucleotide on the other chromosome in the same loci must be T? Doesn't chromosome mean a paired up strand, not a single strand?

  • 1
    $\begingroup$ All chromosomes are double-stranded (they wouldn't be stable otherwise). Diploid organisms have two double-strands, for a total of 4 strands. Haploid organisms one have one double-strand, for a total of 2 strands. $\endgroup$
    – C_Z_
    Jun 30 '16 at 16:09

Is this double stranded property the same as saying an organism is diploid?

No. You are a diploid organism because you have two copies of every chromosome.* You got one from your mother, and one from your father. All your cells are also diploid, except for your gametes, each of which contains only one copy of every chromosome (due to crossing over, each chromosome is partially from your mother, partially from your father).

Bacteria just have one copy of their genome. They duplicate it prior to cell division, and each resulting cell has one copy of each chromosome.

*Unless your sex chromosomes are XY, or are anuploidic.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.