VCE Biology Question Thread

[Chocolatepistachio]

Thanks
For this question would my answer and working out be right

[Owlbird83]

Thanks
For this question would my answer and working out be right

Looks good (I wasn't really sure if I could tell between your upper case 'K' and lowercase, so maybe if someone is marking it try to make them a little more distinct when you write your final answer)

[Chocolatepistachio]

This may be beyond the study design but can someone help with this question. Would my answer and working be right

[Sine]

This may be beyond the study design but can someone help with this question. Would my answer and working be right

You have some correct working out in there but 1 misconception. To help you out I think it would be useful thinking about the equation p + q = 1

[Chocolatepistachio]

is the frequency of the r allele (0.7)2 + 2(0.7 +0.3) + (0.3)2

[Owlbird83]

is the frequency of the r allele (0.7)2 + 2(0.7 +0.3) + (0.3)2

No, that becomes a number over 1, (frequencies are less than one).
As Sine said, the formula p+q=1  is useful, and remember that this means that if you add the frequencies of R and r it adds to one.
Also, maybe I missed something, but I think you already found the correct value of r (q=0.3) ?

[Sine]

Wait what did I get wrong in my earlier working

The left hand side working out and using 0.83.

You found q = 0.3
Thus p = 0.7
So from that, you can see p^2 = 0.49 and you should be able to work out the rest by just plugging stuff into the p^2 + 2pq + q^2 = 1 equation.

[Chocolatepistachio]

 So The frequency of the R allele is 0.7

[SmartWorker]

So The frequency of the R allele is 0.7

Yes because p + q =1
Therefore if q =0.3, then p = 1-0.3 = 0.7

[Chocolatepistachio]

For xylem How does structure affect function.
Would this answer be fine
-  Xylem Transports water and mineral ions from the roots to the leaves. Xylem is made up of vessels and tracheids. Xylem vessels have a thick cellulose cell wall and a hollow lumen. The walls of the xylem vessels contain holes called pits through which water enters the plant. Xylem is made up of elongated dead cells that form a continuous tube. This tube is thickened by coils of lignin that support the tube preventing it from collapsing when water passes through

[hbhangu_31]

I'm doing Biology unit 3/4 in year 11 and i am just confused with what I should be doing right now during holidays. I have a SAC on AOS 2 in two weeks, but I want to revise for unit 3 too. What is everyone else doing with biology during the holidays?

[hbhangu_31]

Also, how did you guys do revision for unit 3 chapters throughout unit 3? In other terms what is your study plan for biology like?

[Chocolatepistachio]

Why do guanine and cytosine have 3 hydrogen bonds whereas adenine and thymine have 2 hydrogen bonds

[1729]

Guanine and Cytosine Base pair has three hydrogen bonds,because the exocyclic NH2 at C2 on Guanine lies opposite to,and can hydrogen bond with,a carbonyl at C2 on Cytosine.

In guanine and cytosine you have more nitrogens exposed to more hydrogens which leads to more intermolecular forces (i.e hydrogen bonds)  Furthermore I should add (in case you are not a chemistry student) that nitrogen has a delta negative charge as it is more electronegative and hence attracts electrons more towards it (in a dipole where two covalently bonded atoms have varying electronegativities). Oxygen has a delta negative charge for similar reasons. However, hydrogen has a delta positive charge as it is more electropositive, and hence lets its electrons be closer to the other covalently bonded atom, in this case, nitrogen. Opposite charges attract.

[Chocolatepistachio]

How would you answer this question/ what would you need to include for 4 marks.
Using examples explain why sex linkage and co-dominance do not produce simple Mendelian ratios