Biology Exam

[dooky]

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An absolute killer of an exam.

[anarchron]

I found it easy. Haha, I just won $20 when I predicted the Homo Florensiesis question was bound to come out.

What did you guys put down for the UV mutation and DNA repair graph question? I decided that the greatest UV damage would be at the intersection between those two values, which was if I remember correctly 270nm

[rlaws06]

It was easier than Exam 1 - there were less difficult conclusions to write.

The question relating to the patient with tuberculosis - I wrote out the evolution of the organism into an antibiotic strain, then read that the tuberculosis returned *after* the antibiotic course had finished.

Overall I was surpised on how little there was on (In-depth descriptions of) *PCR *Linkage *Protein Synthesis and *Meiosis and Mitosis

No real 'NFI' questions for me though, just some questions took a fair amount of time to complete - probably spent too much time on this year's fairly easy Multiple Choice questions.

[tristan88]

I agree - it was easy.

[anarchron]

Originally Posted by rlaws06

It was easier than Exam 1 - there were less difficult conclusions to write.

The question relating to the patient with tuberculosis - I wrote out the evolution of the organism into an antibiotic strain, then read that the tuberculosis returned *after* the antibiotic course had finished.

Well, that was just a relative straightforward question dealing with natural selection. All that was required was variation, differentiation in survival, and production of offspring bearing genetically inherited antibiotic resistant trait.

[rlaws06]

Originally Posted by anarchron

What did you guys put down for the UV mutation and DNA repair graph question? I decided that the greatest UV damage would be at the intersection between those two values, which was if I remember correctly 270nm

I put down 260nm, as that was the wavelength which caused the most 'effective mutation' (or something like that) on the dotted line graph.

[anarchron]

Originally Posted by rlaws06

I put down 260nm, as that was the wavelength which caused the most 'effective mutation' (or something like that) on the dotted line graph.

Yep that sounds right, the intersection between the two values.

[anarchron]

Thank god there were no questions dealing with definitions.

[rlaws06]

Originally Posted by anarchron

Well, that was just a relative straightforward question dealing with natural selection. All that was required was variation, differentiation in survival, and production of offspring bearing genetically inherited antibiotic resistant trait.

Yeh, thats what I wrote down - but the symptoms returned AFTER the course of the antibiotics, so the bacteria didn't necessarily have to become resistant - just enough bacteria needed to somehow survive in order to repopulate inside the patient after the antibiotics had stopped being used.
Maybe the antibiotic-resistant strain of bacteria were selected for in the prescense of antibiotics, but their resistance may have caused them to be less virulent. When the antibiotics stopped, the resistant bacteria may have had a selective disadvantage, and the possibly more virulent anti-biotic sensitive form of the bacteria returned (assuming some organisms managed to survive the antibiotics somehow) to cause the symptoms which were not caused by antibiotic-resistant bacteria.

With that said, there were 3 marks available, so I just went through the standard natural selection evolution template RE: Antibiotic resistance.

[anarchron]

Yep well, the question was regarding how the bacteria managed to come back after the course of the antibiotics. The antibiotics was meant to finish off all the bacteria, but variation existed. Then there was a differentiation of survival with all the non-resistant bacteria being wiped off. The surviving ones then manage to multiply etc etc. I don't think it really mattered that they bacteria reappeared when the antibiotics was stopped, it was how they survived it.

[rlaws06]

Cool - what did everyone put down for the experiment RE: Stem colours (Wild Type and V---- something) and Cross 3 and 4's genotypes?

I was running low on time when I got around to finishing that question, so I wrote that Cross 3 and Cross 4 offspring should both be tested at 20 and 37 degrees, and if they produce the same offspring ratios in each, then they (the parents of Cross 3 and 4) are the same genotype

I'm not sure if that was correct, or if you should put both cross parents through a test cross to determine their genetype

[tristan88]

I had test cross at both 20C and 37C from memory, although not entirely sure.
What did you have as a control for this?

[anarchron]

I had:

Isolate those two groups of parents in a controlled environment at 37 degrees.

Redo the cross. If the cross produced 3:1 ratio then they have the same genotype. If they produced all whatever the phenotype was, then they are both homozygous for that trait.

[boupop]

i also said do test crosses at 20 degrees, but when i think about it, i agree with rlaws, it makes more sense (and that way could have a test cross as a control)

[boupop]

Originally Posted by anarchron

Yep well, the question was regarding how the bacteria managed to come back after the course of the antibiotics. The antibiotics was meant to finish off all the bacteria, but variation existed. Then there was a differentiation of survival with all the non-resistant bacteria being wiped off. The surviving ones then manage to multiply etc etc. I don't think it really mattered that they bacteria reappeared when the antibiotics was stopped, it was how they survived it.

did u say the variation in bacteria in terms of inside the body, or in nature?