Material World , Radio 4’s weekly science show, is running a competition for anyone who has a scientific idea they want to investigate. A level students are eligible to enter, and if you are chosen you will be given help to develop your idea with assistance from top scientific researchers. Everyone has a scientific question they want to investigate! Why not enter this competition and develop yours?
Tags: BBC, Competition
Following on from a discussion in my A2 class this week, my attention has been drawn here. She looks so sad!
Tags: Eyes, Heterochromia, Inheritance
We talked about eye colour inheritance in a recent A2 lesson, and one student asked about how a person can have two different coloured eyes, such as in the example below.
We talked about how eye colouration is polygenic, meaning that more than one gene is involved. So there probably wasn’t a simple answer to the question!
Heterochromia iridum (having two differently coloured eyes) is caused by differing levels of pigmentation in the two eyes. This may be caused by an injury to the eye, which causes one eye to produce too much or too little pigmentation. This is called ‘acquired heterochromia’.
Heterochromia is also present in a number of inherited genetic conditions, such as Waardenburg’s syndrome. Such conditions are usually inherited as a ‘faulty allele’ of a gene, although each case is different (see here for a list of inherited genetic (congenital) disorders associated with heterochromia).
A third possibility is that during embryonic development a mitotic division went wrong. This resulted in an uneven distribution of chromosomes in the daughter cells. This diagram here shows how this could happen through a process called nondisjunction. The result is that some cells only carry one chromosome from a pair and thus only have one version of the gene. If these daughter cells go on to develop into eye pigmentation cells then they can express a recessive allele as they no longer contain the dominant allele. Thus one eye expresses the colour for the recessive allele whilst the other, having cells from a non-changed cell line, expresses the normal dominant allele.
There are a lot of ‘ifs’ in this route, but some cases of heterochromia are caused by this ‘mosaicism’.
David Bowie is famous for having two different coloured eyes. He got his, apparently, from being hit in the face during a fight. So now you know.
Tags: Lactase, Lactose Intolerance, Milk
I was going to write a post about lactose intolerance following on from our lesson on carbohydrate digestion and the production of gas in the intestine from the fermentation of lactose by gut bacteria. However, this site here, produced by a biomedical scientist, does an excellent job of explaining what lactose intolerance is and the biology of the condition. So instead of replicating what is already on the web I thought I would just link to it instead.
Seeing that most people in the world are intolerant to lactose after weaning, is lactose intolerance actually an illness of the digestive system or just the digestive system acting normally?
And finally, a link to a site that explains the difference between an allergy and an intolerance.
Tags: Images, Wellcome Trust
Tags: Biological Sciences Review, Magazine, Wider Reading
The library is now taking subscriptions for the Biological Sciences Review magazine. It is a recommended text for the AS/A2 course. Subscriptions cost £12.50 (reduced rate) and the magazine is published four times throughout the year. If you are interested you should bring a cheque for £12.50 made payable to Turpin Distribution into school as soon as possible and hand it into the library.
As the publisher states on the website:
“Biological Sciences Review is written for students.
Each 44-page issue of Biological Sciences Review explores key topics on the new AS and A2 specifications. Specially written for students, each issue is designed to stretch and challenge their understanding through thought provoking articles.
Regular columns will help students develop understanding and skills. These include:
* Upgrade, Chief Examiner Bill Indge offers invaluable advice to get ahead in exam preparation
* How Science Works, a core element of the new specifications, this new column looks at examples of the ways in which scientists work and the potential impact of their work”
The library stocks past editions of the magazine and will have a subscription for this year also, but you may wish to have your own copy to add to your notes. It’s good.
What’s that? You’re bored of the summer holidays? You need some good science TV to keep your biology appetite satisfied? Well that’s lucky, because BBC have a fantastic series on the cell. It’s called, appropriately, The Cell and is on Wendesday 10pm BBC4. If you haven’t seen it yet you’ve missed the first two episodes, but thankfully the iPlayer has the whole series, so you can catch up.
Proper science telly.