Stuff on DNA

[shinny]

Um for the hydrolysing FULLY one.

It agree its 99. Then a further 100*2 are needed to break bonds between the nucleotide.

So this means 99 + 100*2 = 299.

I'm fairly sure this is right.

You're only hydrolysing the bonds between the nucleotides; not within the nucleotides.

[Martoman]

It says fully. I assume so?

[stonecold]

It just seems illogical to break down a nucleotide...

Anyway, I wouldn't stress.  It's far too ambiguous...there are many answers depending on how the question is interpreted.

[Martoman]

mmmm I don't want bullshit like this on the exam. 

[kenhung123]

Hmm it says COMPLETELY so perhaps it requires 49x2+50+50=198? To break up base+sugar and sugar+phosphate?

[Martoman]

I would think 199?

[physics]

DNA is good if we did bio last year XD

[Mao]

For what it's worth, I definitely agree with matty for the polymerization question, and am leaning towards martoman (299 bonds severed) for the hydrolysis question.

[stonecold]

It depends if we are talking about a single stranded piece of DNA with 100 nucleotides, which does mean it will take 299 water molecules to hydrolyse it.  But if it is a double stranded piece of DNA with 100 nucleotides then:

50 on each strand, so 49 x 2 water molecules to break down into individual nucleotides.  Then 2x100 molecules to fully hydrolyse into separate phosphate, sugar and base molecules, so the answer could also be 298.


I don't think VCAA are very interested in this as a means of testing.  In the 2008 sample exam, there is just a drawing of a double stranded DNA fragment with 9 nucleotide pairs, and they ask how many water molecules are required to break it down into its constituent nucleotides.  Answer is just 16.

On a side note, it may be worth getting familiar with the H-bonding between base pairs:
http://en.wikipedia.org/wiki/DNA#Base_pairing

[m@tty]

For what it's worth, I definitely agree with matty for the polymerization question, and am leaning towards martoman (299 bonds severed) for the hydrolysis question.

Is a gene single stranded?

[Mao]

For what it's worth, I definitely agree with matty for the polymerization question, and am leaning towards martoman (299 bonds severed) for the hydrolysis question.

Is a gene single stranded?

that is debatable. I'll leave it to a biochemist to answer this, I personally have no idea.

[stonecold]

Okay, thought I'd upload this.  It is just the bases from the data book, but I put the polar charges on them just in case we have to draw the hydrogen-bonding between two base pairs.

I think this is right, if not, my teacher really needs to get her shit together.

Anyway just remember, start from the top, and work your way left.  A and T have two polar sites, whilst C and G have 3.  Any group with H in it is always +, whilst O and N on their own are -

Hope this helps, because I was really struggling to match up the molecules but with this it seems a lot easier.

[Martoman]

I usually remember these by the fact that the letters  "CG" is *curvy* like the number 3 and AT are the other number: 2.

And to get them to bond you have to make them go one rotation to the right then a reflection about the "y-axis" (lol methods).

[stonecold]

Do you have to rotate, or can you just reflect?

And umm, y-axis or x-axis?

[Martoman]

about the Y axis if you drew in a Cartesian plane so that (0,0) was in the middle of the ring.


So you rotate the thing one thing to the right then flip it from left to right. Then you have to *grab* it from its place and place it to the left of its purine base. This makes its bonding easy to see.