2014 VCE Biology Exam Solutions by Scooby

[berkouras]

with the crosses, in the past VCAA has required you to state the sex of the resulting offspring from the cross if the sex of each parent is mentioned in the stem of the question or the question.
a key word in that second cross was Purple Male x Lilac Female
even though the gene is not sex-linked, the sex of the parents was mentioned in the question.

a second reason why the second one is more likely to include the sex of the parents in the calculations is because the first one was monohybrid sex linked. why would they waste another question on asking us to do another monohybrid cross? i think they wanted a dihybrid cross

[grannysmith]

with the crosses, in the past VCAA has required you to state the sex of the resulting offspring from the cross if the sex of each parent is mentioned in the stem of the question or the question.
a key word in that second cross was Purple Male x Lilac Female
even though the gene is not sex-linked, the sex of the parents was mentioned in the question.

a second reason why the second one is more likely to include the sex of the parents in the calculations is because the first one was monohybrid sex linked. why would they waste another question on asking us to do another monohybrid cross? i think they wanted a dihybrid cross

What did you do?

[dankfrank420]

with the crosses, in the past VCAA has required you to state the sex of the resulting offspring from the cross if the sex of each parent is mentioned in the stem of the question or the question.
a key word in that second cross was Purple Male x Lilac Female
even though the gene is not sex-linked, the sex of the parents was mentioned in the question.

a second reason why the second one is more likely to include the sex of the parents in the calculations is because the first one was monohybrid sex linked. why would they waste another question on asking us to do another monohybrid cross? i think they wanted a dihybrid cross

If you've got a picture of that question then post it, but I think the reason they included that question was to check if people knew that autosomal traits show no pattern in a particular gender of offspring like sex-linked does. The male and female was a red herring to throw people off and make them write "50% male purple" when really there's no way to tell the gender.

[nerdmmb]

I just wanted to confirm, does VCAA use the SAC scores that you get at school?

[Scooby]

I just wanted to confirm, does VCAA use the SAC scores that you get at school?

Yup, your teacher sends your results (not just rank) to VCAA. Your moderated mark may end up completely different to what your teacher submits though

[berkouras]

If you've got a picture of that question then post it, but I think the reason they included that question was to check if people knew that autosomal traits show no pattern in a particular gender of offspring like sex-linked does. The male and female was a red herring to throw people off and make them write "50% male purple" when really there's no way to tell the gender.

Well, considering in the stem of the question they included the genotypes of the male and female phenotype, yes you are able to tell the gender.
This requires you to perform a dihybrid unlinked cross, with the gender genotype as the first factor and the colour as the second factor.

[dankfrank420]

Well, considering in the stem of the question they included the genotypes of the male and female phenotype, yes you are able to tell the gender.
This requires you to perform a dihybrid unlinked cross, with the gender genotype as the first factor and the colour as the second factor.

Pretty sure the gender was just a red herring because the trait is autosomal.


Besides, you don't determine your sex by your genes - its about which chromosome you receive from dad.

[Reus]

Pretty sure the gender was just a red herring because the trait is autosomal.

Would you not get the mark if you included gender in the phenotype?

[Scrono13]

Well, considering in the stem of the question they included the genotypes of the male and female phenotype, yes you are able to tell the gender.
This requires you to perform a dihybrid unlinked cross, with the gender genotype as the first factor and the colour as the second factor.

This is what I did, but no one else seems to have done it so I thought it was wrong. Is it?

[dankfrank420]

This is what I did, but no one else seems to have done it so I thought it was wrong. Is it?

How could it be a dihybrid cross? Nothing has a 'gene' for gender, its about which chromosome you receive from dad.

[grannysmith]

How could it be a dihybrid cross? Nothing has a 'gene' for gender, its about which chromosome you receive from dad.

Yeah, the question didn't specify what the X linked trait was, so we can't assume it was talking about gender. In this case, gender seems irrelevant as the specific trait they asked for was autosomal, which we know is equally likely to be inherited by either male/female.

[Scrono13]

How could it be a dihybrid cross? Nothing has a 'gene' for gender, its about which chromosome you receive from dad.

I just did like a cross of the phenotype of the dad, which was like ZZBB maybe I can't remember, and a cross with the mum which was maybe ZYBb (I'm making these up, can't rmemeber).
Then dihybrid cross using these two
So ZZBB X ZYBb

[dankfrank420]

I just did like a cross of the phenotype of the dad, which was like ZZBB maybe I can't remember, and a cross with the mum which was maybe ZYBb (I'm making these up, can't rmemeber).
Then dihybrid cross using these two
So ZZBB X ZYBb

The Z's and W's weren't genes - they were chromosomes.