VCE Biology Question Thread

[Scooby]

How does it break off then?

When it reaches the end of the DNA strand it's replicating, it'll dissociate

[ravi2]

are histone proteind found only in chromotins or in chromosomes as well?

[nerdmmb]

are histone proteind found only in chromotins or in chromosomes as well?

Chromatin is a mixture of chromosomes that exists during interphase... So i think it may have histones as well.

[dankfrank420]

Wouldn't histone appear everywhere there is DNA, so logically they should appear in whatever form the genetic material is in?

[nhmn0301]

are histone proteind found only in chromotins or in chromosomes as well?

Just adding up:
Chromatins are the material that make up chromosomes. Imagine you have a histone (like a ball) and wrap it around with DNA (strings), the resulting complex is called a nucleosome (a ball + strings). These nucleosome continues to build up and coil around each other to create chromatin (heaps of balls + strings). These chromatin in turn is supported by a frame of other proteins and result in a tightly packaged chromosome.
So what you are basically asking is like "can we find clay in the brick or in the house?". Hope that clears up a bit !

[vox nihili]

Adding as well, what I think may be confusing some of you is super coiling. Those balls of histones with DNA wrapped around can then wrap around each other, giving you a supercoiled structure and that really condensed chromatin you see during meoisis/mitosis

[nerdmmb]

Are the histone proteins different from the centromere?

Or is it just supercoiled in the centre?

And are there any other proteins that are found in chromosomes?

[vox nihili]

Are the histone proteins different from the centromere?

Or is it just supercoiled in the centre?

And are there any other proteins that are found in chromosomes?

There are other proteins found in chromosomes, but the structure of chromatin is essentially made of histones and DNA.


As far as the centromere is concerned, there are histones present though they are different variants of histones. You're also correct to suggest that they are more tightly coiled in the centromere. This is definitely not knowledge required for VCE.

[sandrab]

is DNA's function just that is contains all the genetic instructions of a living organism, hence determining all the characteristics of that living organism?
thanks in advance

[Reus]

is DNA's function just that is contains all the genetic instructions of a living organism, hence determining all the characteristics of that living organism?
thanks in advance

Yes pretty much.
In an answer you'd probably want to mention that DNA also codes for amino acids -proteins- 

[nerdmmb]

Yes pretty much.
In an answer you'd probably want to mention that DNA also codes for amino acids -proteins- 

And maybe also add that it contains hereditary genetic information

[MM1]

Can someone please explain the term Pleiotropy? Thanks!

Anyone?

It means : the production by a single gene of two or more apparently unrelated effects.
I'm not too sure what that means, can someone explain it? Thankss!

[vox nihili]

Anyone?

It means : the production by a single gene of two or more apparently unrelated effects.
I'm not too sure what that means, can someone explain it? Thankss!

What I had in my notes about it:

"One gene may cause a number of phenotypic effects. A good example earlier was the mutant gene that leads to albinism. It is causing a number of phenotypic changes, all because of one dysfunctional protein. There are a huge number of alleles that show pleiotropy. This is because the body is exceptionally well refined and well balanced, and tends to like to use the same molecules for a variety of things. "

[nerdmmb]

Can someone please tell me if the following are the only gene technologies that we need to know?

-Gel electrophoresis
-Gene cloning
-Polymerase chain reaction
-RNA interference

And just to confirm, are we required to know about the southern blot technique?

Thanks heaps!

[Rishi97]

Does anyone know any good acronyms regarding the steps of genetic engineering? I'm having a bit of trouble remembering everything