Crossingover is the exchange of genetic information between (homologous chromosomes that occurs during meiosis). The anwer options are 1. sex chromosomes 2. sister chromatids 3. chromatids 4. homologues. I chose number 4, but I am uncertain of my answer. Can someone help me, please?

Question

Crossingover is the exchange of genetic information between (homologous chromosomes that occurs during meiosis).  The anwer options are 1. sex chromosomes 2. sister chromatids 3. chromatids 4. homologues.  I chose number 4, but I am uncertain of my answer.  Can someone help me, please?

anonymous · Answer

Chromosomal crossover (or crossing over) is the exchange of genetic material between homologous chromosomes that results in recombinant chromosomes. It is one of the final phases of genetic recombination, which occurs during prophase I of meiosis (pachytene) in a process called synapsis. http://en.wikipedia.org/wiki/Chromosomal_crossover

anonymous · Answer

Meiosis 1: Prophase I - homologous chromosomes are paired up tightly into tetrads, then crossing over, the exchange of genetic material between the DNA in these tetrads occurs, forming a chiasmata, an x-shaped structure. http://en.wikibooks.org/wiki/IB_Biology/Genetics,pt2 What you think?

myst · Answer

Hi Ryaan.  I had the same definition as you above.  It is a bit confusing to me.  They say the exchange of information between homologous chromosomes.  I ruled out sister chromatids cause it should say "non-sister", then sex chromosomes seems not to fit entirely, chromatids might but it is not specific ito "non-sister" which leaves me with homologues.  Homologues seems to related closest to homologous chromosomes, but I am still uncertain.

myst · Answer

Crossing over involves homologous chromosomes exchange "slices" of their own DNA with the non-sister chromatids of a homologous pair. Thus, this results in an exchange of alleles as the alleles from one chromatid are being exchanged with the alleles on a non-sister chromatid.

anonymous · Answer

Okay! its saying [Homologous chromosomes that occurs during meiosis]Right?
Means in Phases of meiosis.
I googled and found!
that
Meiosis 1:
Prophase I - homologous chromosomes are paired up tightly into tetrads, then crossing over, the exchange of genetic material between the DNA in these tetrads occurs, forming a chiasmata, an x-shaped structure.
Metaphase I - paired chromosomes line up along the equator of a cell, the metaphase plate as the spindle microtubulue apparatus pulls them.
Anaphase I - The spindle microtubules pull homologous chromosomes to opposite sides of the cell, causing them to separate.
Telophase I - The spindle microtubule appartus begins to disappear/disintegreate, the nucleus membrane reforms around chromosomes
Cytokenesis I - The cell divides along the equator, creating 2 haploid daughter cells

A brief period of Interphase usually occurs between Meisois I and II, in which the cell grows, and DNA is replicated to prepare for meiosis.
Meiosis 2:
Prophase II - sister chromatids pair up and attach to the spindle microtubule apparatus.
Metaphase II - sister chromatids line up at equator of cell due to the movement of the spindle microtubule apparatus.
Anaphase II - sister chromatids separate as spindle fibers pull them in opposite directions.
Telophase II - sister chromatids are on opposite sides of cell, spindle fibers disappear.
Cytokenesis II - cell divides along the equator, nuclei begin to reform, creating 4 daughter haploid cells.

According to these informations! What I figured out is.. they're asking about homologous chromosome and crossing over and it's only in meiosis 1...see
Meiosis 1:
Prophase I - homologous chromosomes are paired up tightly into tetrads, then crossing over, the exchange of genetic material between the DNA in these tetrads occurs, forming a chiasmata, an x-shaped structure.
 
Does that makes sense? :/
So it should be [4]

I'm sorry I'm still a 9th grader!
This is what I figured out!...

anonymous · Answer

@lncognlto

myst · Answer

Please don't say sorry I do appreciate your effort!  We are all learning as we go along.  I agree with you in terms of the Prophase I - homologous chromosomes are paired up tightly into tetrads, then crossing over, the exchange of genetic material between the DNA in these tetrads occurs, forming a chiasmata, an x-shaped structure.  With focus on exchange of genetic material between the DNA in these tetrads (homologous chromosomes).  I say 4 as well.  Just wondering if Homologues are the same as homologous chromosomes?

anonymous · Answer

Homologous chromosomes also called homologous!

anonymous · Answer

If I'm not mistaken!

anonymous · Answer

I just checked and yes they're the same! here: Homologous chromosomes (also called homologs or homologues) are chromosome pairs of approximately the same length, centromere position, and staining pattern, with genes for the same characteristics at corresponding loci... http://en.wikipedia.org/wiki/Homologous_chromosome

anonymous · Answer

@lncognlto Bro what you think ?/ :/

myst · Answer

I had a look and there is no doubt.  Wonderful mate.  You solved that one.  Thanks man, really do appreciate your inquisitive mind.  Goes to show the question was in front of us all the time.....I have another question I will post.

lncognlto · Answer

Well, the definition of crossing-over is "The exchange of genes between homologous chromosomes, resulting in a mixture of parental characteristics in offspring". So yes, I would agree. (Sorry, I was trying to look up some information)

myst · Answer

You guys are great, special thanks to Ryaan.  And thank you Incognito!  Just great that we could work it out together.  Think Ryaan did more than his share!  Thanks again.

lncognlto · Answer

He did indeed. Well done, Ryaan :)

anonymous · Answer

You're welcome :) And sorry I forgot to welcome you!
[Welcome to OpenStudy]

And Thanks @lncognlto and @myst for appreciating me ! :)

myst · Answer

Always!  Posting another question if you have time.

lncognlto · Answer

:)

Yep, welcome to OS, myst.

myst · Answer

Thanks you guys, cannot believe I found this space, really cool!

anonymous · Answer

You forgot to give @lncognlto a medal! He deserves a medal! 
@myst

myst · Answer

I appreciate Incognito, but you were more actively involved, right?  So the medal should go to you?  I just click on best response or what?

lncognlto · Answer

Ryaan deserves a medal more, though. I did get here a bit late after all :).

myst · Answer

Well, I appreciate all the responses and the medal goes to Ryaan for his extraordinary effort!

lncognlto · Answer

Cool cool, I agree :)

myst · Answer

Incognito just inform me what do you guys do with the medals?  I am new here sorry I am not up to scratch with everything.

lncognlto · Answer

We add them to our shiny collection. Just kidding. The medals help to increase our SmartScore. They are like rewards for the best answer. The CoC has something about them, I think.