AQA A2 Biol4 January 2012 pre- exam discussion

What was the answer about the evidence showing its on the X chromosome or something

Was it not that if it was sex linked, and attached to the x chromosome, then that means a male (who has only 1 x chromosome) would HAVE to have it? something like that, forgot now...

What was the answer about the evidence showing its on the X chromosome or something

I think rainfall would have been fine too, haha.

About the nitrate concentration decreasing?

The fact that, on the diagram, only male offspring were hairless, suggesting hairless females is either impossible or very rare. This shows sex-linkage because females would require two alleles coding for hairlessness to present itself in the phenotype (it's a recessive allele) but in males, there is no homologous portion on the Y chromosome so only one recessive allele is required for them to exhibit hairlessness in the phenotype. Hence, hairlessness is more common in male offspring.

What about wind? LMFAOOOO I wrote wind becase I left that question out, and had about 20 seconds to write an answer. Any chance "wind" would be an answer?

This was a reallly hard paper in my opinion! Think its unfair that there are soo many how science works questions

The fact that, on the diagram, only male offspring were hairless, suggesting hairless females is either impossible or very rare. This shows sex-linkage because females would require two alleles coding for hairlessness to present itself in the phenotype (it's a recessive allele) but in males, there is no homologous portion on the Y chromosome so only one recessive allele is required for them to exhibit hairlessness in the phenotype. Hence, hairlessness is more common in male offspring.

oh yes I wrote that ^_^

I also drew a diagram of this and was like " As you can see, my diagram shows..." LOOL!

Gahh I can't remember >.< I wrote about mutualistic nitrogen fixing bacteria somewhere in the exam though xD
I THINK it was how they use the oxygen to make nitrates, so I put about fixing with Oxygen with the Nitrogen in the sewage to make nitrates >.<

What about wind? LMFAOOOO I wrote wind becase I left that question out, and had about 20 seconds to write an answer. Any chance "wind" would be an answer?

YESYESYES, I put this too.

This was 1 mark... ?
Think I only said the last bit and gave reference to the diagram and talked about the Y choromsome being shorter etc

Facebook group?

Yeah wind is an abiotic factor.

Yeah, I just thought I'd give a full explanation here so people could see the reason if they're not sure. For 1 mark, your answer is probably fine.

I have a bad habit of writing my whole thought process for the examiner to see!

Go for it, I'm becoming less confident about my marks by the minute. :/