Posts Tagged ‘crossing over’

Higher level genetics

Saturday, August 6th, 2011

This is Topic 10.  Syllabus guide here: IB-Biology-HL-Topic-10-syllabus-guide

Hopefully, much of this will be REVIEW.  I’m planning to spend 3 lessons – no more.

Firstly, meiosisHere’s what you need to know. BE CAREFUL with the vocab.

Next, dihybrid crosses and gene linkage.  This is the fun stuff! Presentation here.  PRACTICE makes maybe not perfect, but certainly BETTER 🙂

Lastly, polygenic inheritance.  What is it and how does it work? This will explain.

First assessment of the year will be MONDAY 15th AUGUST.

What phase of meiosis is shown in this picture?


Wednesday, April 13th, 2011

genes on parade by Esthr on flickr

Here are some of the terms we will get to terms with in this section 🙂

diploid, haploid, homologous chromosomes, crossing over, non-disjunction, trisomy, karyotyping

  • We’ll learn about the process of meiosis, and why it is known as a reduction division.
  • We’ll understand how chromosome abnormalities such as Down’s syndrome come about.
  • We’ll learn what a karyotype is and how to analyse one.
  • And we’ll discuss some ethical issues to do with karyotyping of unborn fetuses. 

There are a number of ToK links here, such as balancing the risks of side-effects with preparing for a chromosome abnormality in an unborn child.  There are also questions raised about who should make the decision about whether to perform the karyotype – the parents, doctors, governments?

Here is Mr Taylor’s presentation on this topic.  And here is a very very very dated but well done video.   Biologix__Meiosis_and_Gamete_Formation

We’ll use this site – The Biology Project – to practise karyotyping.