Tuesday, 19 October 2010

S377: The exam

The exam - and one I have not been looking forward to.
There are just so many things that they can test you on here, it seems impossible to revise everything. Some things seems to come up regularly. Cancer, and cell structural proteins - but they are both quite big subjects.
Others seem to come up at random.

The format is to do eight questions out of 12 in the first part - all of these worth 10 points. Then answer questions on a research paper that you have been given beforehand for the remaining 20 points.

Q1 is about the microfilament network. I'm better on the microtubule network, but I gave this a go.

Q2 looked horrendous, asking you to draw a sketch graph of the activation energy of an enzyme catalysed reaction. After reflecting on it for a bit though - I decided this was really just the same as a normal chemical reaction graph that I'd done in S205. I'm hoping so anyway - so tried that too. Also covered SDM and catalytic sites.

Q3 was about membrane proteins and included secondary and tertiary structure questions. I tried this one too.

Q4 was about eukaryotic nucleosomes and apoptosis. I tried this, but really couldn't remember half the proteins involved (well half is probably an overstatement - I don't think I got any of them - until I was walking down the street after the exam!).

Q5 was about mRNA splicing and the removal of introns. It also covered RNAi methods - I tried this, but again couldn't remember the relevant proteins.

Q6 was about ribosomes, and I tried this working from first principles. I knew how they worked, but hadn't revised any of the details, so I sort of shot in the dark for the explanations they required.

Q7 was about RTK signalling receptors. I had revised this - but not quite in the form the question was asking. I scratched around - trawled my memory, and guessed at some of it.

Q8 was about apoptosis and necrosis, and a bit about tumour development. I tried this too.

Q9 was about tumour development - but I couldn't remember the techniques they asked about. I think I skipped this one

Q10 was about small G proteins, RAS and VEGF. I tried this one too.

Q11 was about ageing and mitochondria. I might have attempted this - I can't remember. I wouldn't have got far if so.

Q12 was about stem cells, intestinal cells and the WNT pathway. I couldn't remember enough detail to attempt this one.

The paper is a bit of a shock to most of us. Not so many of the common topics seem to come up, and quite a few oddities come out of the woodwork in the first part. Stuff that hasn't been on previous years papers and I think many of us were scratching around for things we could answer. In the end I did manage to find 8 questions to answer, but some of them rather badly. It was good in that the first question I could answer, but then as I scanned down the paper, circling those I might try, I'd got to the last question and only ringed about 3, and some of those rather hesitantly. At the end I attempted a couple more questions as I had lots of time spare, to see if I fared any better.

In contrast the research paper seemed a lot nicer - there were a couple of questions that had to be answered with knowledge from the course, rather than digging out figures and things.

So all in all - a bit of a shock and although it was never going to be an easy paper - it was harder than most of us were expecting I think.

Tuesday, 12 October 2010

S366: The exam

The exam - oh my!

So the exam comes around, as always a bit of a tense time. The exam consists of several sections.
The first section is 10 questions which comes in pairs. You have to answer 1 from each pair, plus two others. So 7 questions in total from 10, but narrowed down so you have to be able to focus on the topics within each pair.

Q1 concerns 5 statements, and you have to explain why each of them is false. From mutations to molecular clocks to the allometry of horses teeth.
Q2 picks pairs of definitions and you have to explain why they are related.
I did both of these in the end, despite not quite knowing what one of the terms was.

Q3 Is about area cladograms and vicariance. Two subjects that didn't stick with me, so I missed this out.
Q4 Is about mass extinctions and what can cause them. I attempted this one

Q5 Is about the neutral theory of evolution, and molecular clocks
Q6 Concerns the different type of selection, directional, stabilising and disruptive.
Both of these tried

Q7 is about birds and sexual selection, and life balance trade offs. I tried this one.
Q8 is about allopatric selection. I wished I could remember exactly what that was - on the day I wasn't certain enough to attempt it.

Q9 Is about chromosome counts and how breeding possibilities between near relatives such as horse and donkey. I tried this one
Q10 Is about morphological constraints and how they affect things - I think I skipped this one

The next section part 2 and mandatory, is usually a question on cladograms. You have to be able to draw one usually, and usually amend it. In this exam we had to draw the given one with state changes marked on it. Then redraw it in a different format, and see which version was more parsimonious. It concerned various birds and their ancestors. I found the cladograms easier to draw than I had on mocks for this one, although I messed up the definition of sister taxon, drawing a line parallel to its sister, rather than a branch. It became obvious when the two tree lengths were the same. After looking at it for a time, and checking all the transformation states twice, I spotted the branch and everything became better.

Part 3 is also mandatory and is to do with graphs and data associated with the breeding date of birds. You are then asked to relate these things to natural selection and say whats going on. Based on the results you found you then had to infer a few things about their histories.

Finally part 4 is about a paper that you are given before hand and have to read. Then the question asks various things about the paper, and the evolutionary concepts it relates to. The paper is one from Scientific American about the loss of hair in humans, the probable time it happened and the reasons behind it. I think this went ok - but its all a bit hazy now.

All in all, it wasn't a bad exam. I'm not sure I'll have done staggering well, but enough to pass I think. It was a fair test of the stuff learnt on the course, and seemed eminently achievable. I could have done better, I could have been better prepared for some of the questions - but that is always the case. In contrast to my other exam - this seemed like a breeze!