4.2+Meiosis

4 Genetics - 4.1 Chromosomes, genes, alleles and mutations - 4.2 Meiosis - 4.3 Theoretical genetics - 4.4 Genetic engineering and biotechnology - Genetics Labs

4.2 //(and 10.1)// Meiosis
4.2 Core
 * Assessment statements ** (IBO notes added to some point to clearly indicate what needs to be understood and what does not)
 * 4.2.1 || State that meiosis is a reduction division of a diploid nucleus to form haploid nuclei. ||
 * 4.2.2 || Define homologous chromosomes. ||
 * 4.2.3 || Outline the process of meiosis, including pairing of homologous chromosomes and crossing over, followed by two divisions, which results in four haploid cells. Limit crossing over to the exchange of genetic material between non-sister chromatids during prophase I. Names of the stages are required. ||
 * 4.2.4 || Explain that non-disjunction can lead to changes in chromosome number, illustrated by reference to Down syndrome (trisomy 21). The characteristics of Down syndrome are not required. ||
 * 4.2.5 || State that, in karyotyping, chromosomes are arranged in pairs according to their size and structure. ||
 * 4.2.6 || State that karyotyping is performed using cells collected by chorionic villus sampling or amniocentesis, for pre-natal diagnosis of chromosome abnormalities. ||
 * 4.2.7 || Analyse a human karyotype to determine gender and whether non-disjunction has occurred. ||

//10.1 HL//
 * //10.1.1// || //Describe the behaviour of the chromosomes in the phases of meiosis.// ||
 * //10.1.2// || //Outline the formation of chiasmata in the process of crossing over.// ||
 * //10.1.3// || //Explain how meiosis results in an effectively infinite genetic variety in gametes through crossing over in prophase I and random orientation in metaphase I.// ||
 * //10.1.4// || //State Mendel’s law of independent assortment.// ||
 * //10.1.5// || //Explain the relationship between Mendel’s law of independent assortment and meiosis.// ||

// N.B. This topic links to 10.1 Meiosis which HL students will be studying in conjunction with this topic. This page contains both Core and AHL content. AHL specific content is written in italics //

Log in to the [|DCS Bridge] to obtain your workbooks and supporting resources
 * Workbooks and Worksheets **

An alternative set of notes from [|i-Biology] can be found here media type="custom" key="23840204" //and here for HL and SL together (despite the misleading header)// media type="custom" key="23840208"

Steven Taylor ([|i-Biology]) has a great presentation to view and take notes from before starting your notebook for SL media type="custom" key="23840212" //And additionally for HL// media type="custom" key="23840214"
 * Presentations and tutorials **

//Jason De Nys also has a very good presentation to use for note development for AHL// media type="custom" key="24508294"

Understanding supercoiling is key before considering either mitosis or meosis

The khan academy has a video tutorials on the [|Phases of Meosis]

Use the teaching and visualization animation from St Olaf to gain an overview of meiosis

[|Meosis (from Biostudio)] is key to understanding not just genetics, but also reproduction and consequently Evolution too

[|Non-disjunction and Trisomy] occurs when Meosis goes wrong. You should be able to identify these types of genetic disorders from karotypes. These Biostudio animations show non-disjunction happening during [|Meosis I] and [|Meosis II]

[|Amniocentesis] is a medical procedure used to test babies suspected of having a genetic disorder. Here is a [|video showing the process] happening for real.

[|Gender testing courtesy of HHMI] and what makes us male or female, is an interesting area to debate, it’s not simply a matter of XX or XY. FYI gender in reptiles is often determined by the temperature at which eggs are incubated.

//HL students should recognise the difference between and the importance of both [|random orientation] and [|independent assortment]//

Use click4biology for [|SL] and //[|additionally HL]// to review and complete your notes

> a. Normal meiosis > b. An explanation of non-disjunction > //c. Additionally HL students should include crossing over and chiasma// > Here's good example by a teacher (a little dry, but explains the concepts well). n.b. only the second part is on meiosis > > > > > - the genetic causes of DS > - the physical features of someone with DS > - explain why women who are older are more likely to have a baby with DS > - how to test for DS – include amniocentesis and chorionic villus sampling > - the ethical and practical pros and cons of testing for DS > > Examples of Student Work
 * Activities**
 * 1) Produce a short video using stop gap animation to show the process of meiosis include in your video:
 * 1) View the efforts of other groups and give constructive criticism - give suggestions of how they could of improved their video in terms of content and communication
 * 1) Go through the [|gender testing tutorial] and discuss your decisions on gender at each stage.Read [|Semenya 'let down' in gender row] and [|IOC draws up rules to avoid gender rows at London 2012] to get a perspective on the different views of gender testing in athletics and how it affected one athlete in particular.
 * 1) Complete your workbook during this class their will be opportunities for tutorials on the different assessment statements.
 * 1) Make an information leaflet for parents concerned about their children getting Down Syndrome (DS). Include:

These extended response questions give you an idea of the detail and how to structure answers about Meosis media type="custom" key="23840216"
 * Review**


 * Useful Links **

Read [|Semenya 'let down' in gender row] and [|IOC draws up rules to avoid gender rows at London 2012] to get a perspective on the different views of gender testing in athletics and how it affected one athlete in particular.

TOK: Is the male chromosome decaying will men become extinct. These articles from [|bbc news] and [|New scientist] is a good read and an interesting point to discuss or research further.