confused! Bio question...help

[JustwantDDS]

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Ok, either I'm being really stupid....or really tired... whatever it is
for some reason this isnt clicking for me.

ok so- my question is....
autosomes- and NON sex cell chromosomes right
the sex chromosomes are X, Y
Humans have 23 chromosomes, 22 autosomes, 1 sex chromosome right?

so in SEX CELLS (ova, sperm) are there only x, y chromosomes?

and with barr bodies- inactivated x- why does barrons say theres an inactivated x in every somatic cell? [somatic...are body cells..so wouldnt they not have any sex chromosomes??]

this sounds like a jumbled mess , does anybody get what im saying?😕

 

[Molarcule]

Ok, either I'm being really stupid....or really tired... whatever it is
for some reason this isnt clicking for me.

ok so- my question is....
autosomes- and NON sex cell chromosomes right
the sex chromosomes are X, Y
Humans have 23 chromosomes, 22 autosomes, 1 sex chromosome right?

so in SEX CELLS (ova, sperm) are there only x, y chromosomes?

and with barr bodies- inactivated x- why does barrons say theres an inactivated x in every somatic cell? [somatic...are body cells..so wouldnt they not have any sex chromosomes??]

this sounds like a jumbled mess , does anybody get what im saying?😕

Although I can't explain this fully to you. But from what I know somatic cells are cells that regularly reproduce by mitosis (ex:intestinal cells,skin cells, etc). Sex cells like sperm and ova are the only cells that reproduce through meiosis. That is why somatic cells don't have any sex chromosomes

 

[JustwantDDS]

thats what i thought too, that somatic cells dont have sex CH
but i was just reading about barr bodies in Barrons Ap BIo and it says theres an inactivated X in every somatic cell.

 

[Molarcule]

thats what i thought too, that somatic cells dont have sex CH
but i was just reading about barr bodies in Barrons Ap BIo and it says theres an inactivated X in every somatic cell.

Hmm...guess that would make sense too because all cells have a copy of the complete DNA.

 

[JustwantDDS]

i still dont get it 🙁

 

[PhansterZ]

Ok, either I'm being really stupid....or really tired... whatever it is
for some reason this isnt clicking for me.

ok so- my question is....
autosomes- and NON sex cell chromosomes right
the sex chromosomes are X, Y
Humans have 23 chromosomes, 22 autosomes, 1 sex chromosome right?

so in SEX CELLS (ova, sperm) are there only x, y chromosomes?

and with barr bodies- inactivated x- why does barrons say theres an inactivated x in every somatic cell? [somatic...are body cells..so wouldnt they not have any sex chromosomes??]

this sounds like a jumbled mess , does anybody get what im saying?😕

You're getting confused over autosomes and somatic cells, they aren't the same.

Like you said earlier, we have 22 autosomes from dad and 22 autosomes from mom. These give us non-sex related traits.

We have 2 sex chromosomes, each one coming from each parent. Mom will always give us X, while dad can give us X or Y.
If the combination is XX, you get a female.
If the combination is XY, you get a male.

Barr bodies are when one of the X gets inactivated, which means that the recessive genes on the other X chromosomes may stand out more.

Somatic cells are body cells, which means, they are in your body (diploid).
Each somatic cell has 2 sets of chromosomes (23 from mom and 23 from dad) for a total of 46 chromosomes.

I hope this helps.

 

[Troyvdg]

You're getting confused over autosomes and somatic cells, they aren't the same.

Like you said earlier, we have 22 autosomes from dad and 22 autosomes from mom. These give us non-sex related traits.

We have 2 sex chromosomes, each one coming from each parent. Mom will always give us X, while dad can give us X or Y.
If the combination is XX, you get a female.
If the combination is XY, you get a male.

Barr bodies are when one of the X gets inactivated, which means that the recessive genes on the other X chromosomes may stand out more.

Somatic cells are body cells, which means, they are in your body (diploid).
Each somatic cell has 2 sets of chromosomes (23 from mom and 23 from dad) for a total of 46 chromosomes.

I hope this helps.

👍
to simplify, every cell has the exact same DNA content, autosomes and sex chromosomes.

its differential expression of DNA that gives rise to different cell types, which is where the inactivation of X chromosome in somatic cells would come in to play.

However, sex cells will only contain half number of chromosomes when compared to somatic cells (because sex cells are haploid)
paternal haploid 👎 + maternal haploid 👎 = diploid (2n) --> if confused by this refer to meiosis

 

[reztab]

An egg and sperm, each have one set (N) of chromosome, 22 autosomes and one sex chromosome. Think of it this way, we all are 2N(diploid), and thus each parent has to contribute only one set of our chromosomes.
for girls 22 autosomes and a X from mom and another 22+X from dad. in boys 22+X from mom and 22+Y from dad.
Now about bar body. In females, despite having one extra X chromosome than males, the level of gene expression for those on X (and not determining the female characteristics) are the same as males, why??? because one of the X chromosomes in all females somatic cells is inactivated.
this inactivation happens in morola stage(16 cells) of the embryonic development, and it is completely random. inactivated X can be from mom or dad. That is why female cats, for example, with a yellow and a black parents, is always yellow-black spotted. because the color is X-linked and which x is inactivated is random.
hope it helped

 

[JustwantDDS]

👍
to simplify, every cell has the exact same DNA content, autosomes and sex chromosomes.

its differential expression of DNA that gives rise to different cell types, which is where the inactivation of X chromosome in somatic cells would come in to play.

However, sex cells will only contain half number of chromosomes when compared to somatic cells (because sex cells are haploid)
paternal haploid 👎 + maternal haploid 👎 = diploid (2n) --> if confused by this refer to meiosis

ohhhhhhhhhh got it.👍