Wednesday, 18 April 2007

S103: Block 10 - Earth and life through time, TMA-8

Block 10 - nearly at the end now. Its back to rocks and fossils this time.
There is a fair bit of detail in this block, covering how rocks are laid down, how they can change over time and so on. This is also where you get to look at the fossils that came with the experimental kit several months ago.

There are sections on fossilisation and the early history of life, a chapter all about crystalline minerals and how to recognise them. Then some words about igneous rocks and how they can occur in different formats and structures. Then consideration of sedimentary rocks and the important distinctions that show their history (a good DVD program about this). Then finally metamorphic rocks, and what they're all about.

Then some words on geologic time, and some details of the UKs geology. There are some DVD exercises to do, most of which I get wrong!

However - I elected to do this TMA, so its time to get started.
The first question you have to fill in a table of descriptions that is partially filled in. There is an igneous, metamorphic and sedimentary example. This question is a bit confused by them printing some of the captions wrong. Also I assumed they wanted similar amounts of detail to their sample text, but it turned out they wanted a fair bit more. You also had to draw a sample of how a particular layering would look, and describe the consequent history of the region

The second question is about describing how felsic rocks can be made by fractional crystallisation from more mafic rocks. Apparently they wanted a number of examples for this question, which I didn't include!
The second half got you to explain how uranium/lead dating is done.

The third question is an essay og 800 words on "How interactions between the Earth systems affect the climate". That isn't too bad, although it IS an essay, and I did reasonably well on it.

However from all the points drop in the first questions, and the fact that its difficult to get close to full marks on any essay, its my worst TMA of the whole course. Oh well, thats it for me and TMAs - I only have the End of Course Assessment (ECA) to do now.

Thursday, 5 April 2007

S204: TMA-2

Time to tackle TMA-2. I got a reasonably good mark for TMA-1, so some of my nervousness about level 2 faded. However TMA-2 was here, and oh look - another essay to do! The rest of the TMA is a write up of the experiment done in experimental week 1.

Question 1 is the write up question. You have to write up the experiment as though it was a scientific paper with all the sections. Title, Abstract, Introduction, Methods, Results, Discussion and References. They also give quite tight word counts for each section, and an overall word count to limit you. Also required are diagrams, two graphs with error bars, a set of tables and the results of the statistical analysis together with the confidence rating of the result from the t-test. It takes a number of goes to put all this together and lay it out in a reasonable way, and to keep within the word counts.

Question two is an essay "How different species trade-off the allocation of resources in varying ways to maintain essential activities". It focuses attention on various trade offs, but is a bit of a broad subject. It covers a number of book two topics including longevity, food supplies, surviving the winter. However you can bring in so much stuff to this topic is more difficult knowing where to stop.

Anyway, after a few weeks tweaking, changing and fiddling I posted it off, and got a better mark than my first one, so I was pleased with the results, but it took an awful lot of time to put this TMA together.

Sunday, 1 April 2007

S103: Block 9 - Continuity and Change, TMA-7

Onwards to block 9 - and its more biology.

The fact that block 8 is encouraged to be read kicks in straight away. There is a fair bit of biochemistry in the early chapters as they discuss biological polymers like proteins, nucleic acids and lipids.

Then it is off into the rather complex TCA cycle, also known as the Krebs cycle, or vitamin-C cycle. This is how nearly all living things make energy. It covers this material in reasonable depth, and has a very nice animation and explanation in an accompanying computer program.
This gets a little confusing for me, because at a similar time studying S204 it also starts to cover the same material and in even more detail.

After that, its into the other end of energy mechanisms, where the photosynthetic reactions are covered.
Then, the next collection of chapters is all about DNA and genetics, and then leads into evolution and a bit about speciation.

Now the TMA on this block.
The first question is a nice easy one. Its just a paragraph about Lynn Margulis and her theory of the symbiotic relationship between mitochondria and the eukaryotic cell. You have to fill in the blanks from the given words. Its a nice and easy 8 marks.

Question 2 is about lactose, and starts off by getting you to show how the molecule is built up from glucose and galactose. Then it considers the effects of lactose (in)tolerance and how it might have come about by an evolutionary path. It also involves a genetic mating diagram, a bit of DNA decoding and a short essay. There are 7 sub-parts to the question, with 31 marks available here.

Question 3 looks at two genes and considers linkage between them. You have to draw diagrams of the chromosomes and how they might possibly split when meiosis occurs. 14 marks.

Question 4 and there are 7 marks for explaining the term regulating mortality factor as it applies to holly leaf miners.

Question 5 - they saved the biggy for last. 40 marks for a 700-800 word essay on the subject of "The metabolism of green plant cells in relation to energy exchange processes". Wow - this is a big subject. You have to cover both respiration and photosynthesis and the energy exchanges that are undertaken - all in 700-800 words. I draw a rather fine diagram in word covering the whole glucose oxidation and electron transport chain, and then rereading the question find that all diagrams must be hand drawn. After spending over an hour tweaking this diagram I am more than a little miffed I didn't notice these instructions earlier. I contacted my tutor to see if there was any way to salvage this. It seems silly to print it out and then trace over it or similar. I can't see why they insist on it being hand drawn either. I was in two minds, just delete the whole thing or include it and hope I only loose 1 mark, but gain a couple for the detail.
In the end I kept the diagram in, as my tutor didn't seem too concerned about it. However my planned diagram on photosynthesis never sees the light of day!
I lost a mark or two on this essay for not including any chemical equations - but otherwise I get a pretty good mark for it.