Tutorial Tues 18 August

For those of you that weren't at the tutorial on Tuesday, here is a summary of what we discussed.

We discussed Chapter 3 of Nelson. The first part of the chapter gave some details of statistical analysis, and went on to talk about Activation energy, and how it was related to a distribution of molecules. Not all molecules in the system will have the same energy and the high energy molecules are the ones that are able to get over the barrier first.

There also seemed to be two sections of Chapter 3, which seemed to be unrelated at first glance. We spent a little bit of time discussing the link between the two sections, and concluded that the second part of the chapter was trying to emphasis that there was a stable entity that could encode genetic information, and the stability arose from the high activation energy due to chemical bonds.

We talked about how the distribution of energy of molecules in a system had a Gaussian shape, and that this held regardless of the details of the system (the type of molecules, for example), as long as we could treat the system as an ideal gas.

We also discussed how crossing over is a process which creates diversity, and that it would probably be a rare occurance. The genetics section was trying to emphasise the point that if we take simple physical arguments, and apply statistical reasoning, we can infer things that we can't see - in this case, the encoding of information. It is also important to be able to find a good model system. For most genetics work, this model system is Drosophila Melanogaster, the fruit fly, which enabled study of genes more easily as it has large polytene chromosomes present in its saliva.