Biology Exam: Answers and Discussion!

[dankfrank420]

Did you guys get Xlinked recessive for the pedigree in the short answer ?

autosomal recessive

We can all agree its recessive.

But two daughters had the trait, so if it was x-linked then the father must have had it. He does not, so its autosomal.

[someone011]

Yeah I described allopatric speciation.

I didn't even think of this! I was going on about a mutation which was advantageous due to some environmental pressures, then natural selection acted to the point that these organisms became reproductively isolated, and the old species died out and was replaced by the new one. Definitely 0 marks.

[bonkbadonk]

Did you guys get Xlinked recessive for the pedigree in the short answer ?

I got autosomal because if it were X-linked, then the affected female (in the second generation I think?) would have given it to all her sons, but one of them didnt so it couldn't be X-linked. But recessive is correct as two unaffected parents had an affected child. Double whammy question, it was worth three marks too - one for the correct inheritance and two explanations

[sandrab]

SHIT I MEANT AUTSOMAL BUT I THINK I WROTE XLINKED SHITTTTTTTTT I WAS IN A RUSG

[Coralista]

I didn't even think of this! I was going on about a mutation which was advantageous due to some environmental pressures, then natural selection acted to the point that these organisms became reproductively isolated, and the old species died out and was replaced by the new one. Definitely 0 marks.

Yeah I talked about mutation as well. I thought allopatric speciation would result in divergent evolution so it would be branched out rather than leading straight to that new variation

[katiesaliba]

Yeah I talked about mutation as well. I thought allopatric speciation would result in divergent evolution so it would be branched out rather than leading straight to that new variation

I talked about natural selection/mutations because, as you've mentioned, it didn't branch out but rather evolved in a linear fashion, hence NS.

[milica96]

Hey guys! Will be posting a copy of the exam in about 10 mins while I scan all the pages. I managed to sneak a spare from the assessor 

[dankfrank420]

Hey guys! Will be posting a copy of the exam in about 10 mins while I scan all the pages. I managed to sneak a spare from the assessor 

champ

[katiesaliba]

I was so confused about that one - i said natural selection too, but i said that climate was the selection pressure - so unsure about that haha

Very confusing indeed :\\ I don't see how it wouldn't be natural selection!

Hey guys! Will be posting a copy of the exam in about 10 mins while I scan all the pages. I managed to sneak a spare from the assessor 

Awesome! Kudos to you for your stealthiness  

[Reus]

I talked about natural selection/mutations because, as you've mentioned, it didn't branch out but rather evolved in a linear fashion, hence NS.

I was so confused about that one - i said natural selection too, but i said that climate was the selection pressure - so unsure about that haha

Let's hope it was NS, for my sake

Hey guys! Will be posting a copy of the exam in about 10 mins while I scan all the pages. I managed to sneak a spare from the assessor 

MVP!

[Fingerscrossed]

With the drawing of the antigen-antibody complex, could both antigen-binding sites be bound to the same antigen???

[katiesaliba]

With the drawing of the antigen-antibody complex, could both antigen-binding sites be bound to the same antigen???

Not the same antigen, no.

[Fingerscrossed]

Not the same antigen, no.

Aww...We never learnt that at school so that's more marks lost! 

[Reus]

Not the same antigen, no.

It can be with the same pathogen though right?

[milica96]

UPDATE: sorry for the hold up. running into tech difficulties, the file is too large even when compressed