The Biological Question Thread

[stonecold]

this might sound like an ignorant question, but are the X and Y chromosomes a homologous pair?

For the purpose of meiosis, yeah.  And also, the Y chromosome has some homologous regions with the X chromosome.  i.e. It has some of the same genes.  These regions can undergo crossing over with the X chromosome, but I don't think we are required to know it.

[lexitu]

Nah very fair question. They are But they do not form a chiasma because different genes are held on them.

Hmm interesting stonecold

[Russ]

this might sound like an ignorant question, but are the X and Y chromosomes a homologous pair?

Yes, in theory. They pair during meiosis but don't have the same loci. You'll get different answers depending on which textbook you read, but I think of them as homologous

[lexitu]

I'm pretty sure I've seen VCAA refer to them as homologous but don't quote me on that.

[sillysmile]

wow, awesome to know guys

[stonecold]

Nah very fair question. They are But they do not form a chiasma because different genes are held on them.

Hmm interesting stonecold

It was in the 2008 NEAP exam IIRC.

They are called pseudoautosomal regions.

http://en.wikipedia.org/wiki/Pseudoautosomal_region

[lexitu]

Oh okay. Far out, although it's nice to know, it annoys me that these things are included on exams geared towards VCE students, clearly not necessary.

[sillysmile]

also, what are the satellite endings on chromosomes, and how are they relevant to the karyotyping of chromosomes?

[stonecold]

Oh okay. Far out, although it's nice to know, it annoys me that these things are included on exams geared towards VCE students, clearly not necessary.

The translocation Q in STAV 2008 left me with no idea about what to do...   They really do go too far sometimes.

[sillysmile]

Nah very fair question. They are But they do not form a chiasma because different genes are held on them.

Hmm interesting stonecold

It was in the 2008 NEAP exam IIRC.

They are called pseudoautosomal regions.

http://en.wikipedia.org/wiki/Pseudoautosomal_region

the NEAP exams, always seem to have information which is slightly out of the area of information that we need to know.

[sillysmile]

Oh okay. Far out, although it's nice to know, it annoys me that these things are included on exams geared towards VCE students, clearly not necessary.

The translocation Q in STAV 2008 left me with no idea about what to do...   They really do go too far sometimes.

but, I believe that translocation could actually come up in the biology exam

[Russ]

also, what are the satellite endings on chromosomes, and how are they relevant to the karyotyping of chromosomes?

They're just differently dense regions of chromatin, so they stain slightly differently and thus can be used to determine chromosomes for karyotyping. Seriously doubt you need to know that.

The translocation Q in STAV 2008 left me with no idea about what to do

If that was the one you posted, then there's no way it'll come up. You need to know what a translocation is, not the mechanics of a cross with altered chromosomes (they suck)

[stonecold]

If that was the one you posted, then there's no way it'll come up. You need to know what a translocation is, not the mechanics of a cross with altered chromosomes (they suck)

Yeah, it was that one.

Was the biology Exam always one of the first?  I wish it was later so I would have more time to study for it.

[Russ]

Don't know, didn't do it. I think they should have stuck with english on a friday though.

[sillysmile]

okay, so do ligase enzymes anneal the complementary base pairs, or the DNA backbone?