from The Open University
Alternatively you can skip the navigation by pressing 'Enter'.
Get Started menu item
What's On menu item
TV
-
Friday 24th May
- 12:01am, Eden, Secrets Of Our Living Planet: Magical Forest
- 12:05am, BBC Four, Timewatch: Last Day of WW1
- 11:00am, Eden, Life In Cold Blood
- 11:00am, Eden, Life In Cold Blood
- 3:00pm, Eden, Life In Cold Blood
- 3:00pm, Eden, Life In Cold Blood
- 8:00pm, Eden, Life In Cold Blood
- 8:00pm, Eden, Life In Cold Blood
- Saturday 25th May
Radio
- Friday 24th May
- Sunday 26th May
- Monday 27th May
-
Friday 24th May
Meiosis and mitosis
This Unit looks at how units if inheritance are transmitted from one...
This Unit looks at how units if inheritance are transmitted from one generation to the next. First you will look at what happens to the chromosones of animals and plants during the process of sexual reproduciton. Then you will examine how genes are transmitted in particular patterns from generation to generation. These two approaches combine to illustrate how the patterns of inheritance can be explained by the behaviour of chromosomes during sexual reproduction.
After studying this unit you should know:
- the number of chromosomes is characteristic of each species and can vary enormously between species
- genetics is based on the concept of the gene as the unit of inheritance
- that sexual reproduction always includes two distinctive processes: the production of gametes, which involves meiosis, and fertilisation. The two processes are accompanied by changes in the chromosome number, from diploid to haploid and from haploid to diploid, respectively
- a particular phenotypic character is determined by the two copies of a gene that an organism possesses and these two copies are identical in a pure-breeding variety
- when organisms with contrasting characters for which they are pure-breeding are crossed, the dominant character appears in the first offspring or first filial generation and the recessive character is masked
- the genotypic ratios of a cross result from the separation of the two copies of a gene to different gametes in equal numbers, and because gametes combine at random at fertilisation. The expected ratios in genetics do not tell us the actual ratios observed, but rather the most probable ratios
- the behaviour of chromosomes at meiosis explains the segregation of the two copies of a gene and the independent assortment of genes. The linkage of genes on a chromosome can be broken by means of crossing over
- recombination – the production of new combinations of alleles – arises during meiosis from independent assortment of chromosomes and crossing over between homologous chromosomes
- the amount of crossing over between linked genes differs according to their distance apart.
- Duration: 8 hours
- Published on: Thursday 21st July 2011
- Level: Introductory
- Posted under: Biology
Meiosis and mitosis
Introduction

This unit looks at how units if inheritance are transmitted from one generation to the next. First you will look at what happens to the chromosomes of animals and plants during the process of sexual reproduction. Then you will examine how genes are transmitted in particular patterns from generation to generation. These two approaches combine to illustrate how the patterns of inheritance can be explained by the behaviour of chromosomes during sexual reproduction.
This unit is from our archive and is an adapted extract from Discovering science (S103) which is no longer taught by The Open University. If you want to study formally with us, you may wish to explore other courses we offer in this subject area [Tip: hold Ctrl and click a link to open it in a new tab. (Hide tip)] .
Archive content
This is an extract from an Open University course which is no longer available to new students. If you found this interesting you could explore more free Biology course units or view the range of currently available OU Biology courses.
Other pages You might like

Try: DNA, RNA and protein formation
How is genetic information stored in cells, and how is the information accessed and used?...

Try: Vaccination
Vaccinations are now considered a part of everyday life, but how do they work? This unit...

Study: Practical science: biology and health
Study a range of practical activities in biology and health science – from fundamental...

Try: Plants and people
What techniques are used to keep crops safe from insects? What happens to tomatoes when...

Try: BSE and vCJD: Their biology and...
The furore surrounding the so-called ‘mad cow’ diseases is an important and...

Try: Understanding cardiovascular diseases
Your heart beats around 100,000 times every day and, in that time, pumps about 23,000...

Try: Gene testing
This Unit looks at three different uses of genetic testing: pre-natal diagnosis,...

Try: Early development
This unit looks at the human being in the context of an individual life cycle, examining...

Try: Gene manipulation in plants
Genetic manipulation of crops is an issue of great current interest and controversy. This...

Try: Microbes – friend or foe?
Microbes often get a bad name. Whilst some of them do cause disease, others play vital...

Try: Nutrition: Proteins
This Unit studies 'proteins'. Starting with a simple analysis of the molecular make up,...

Try: Hearing
Hearing is a familiar and important human sense that is a topic naturally of interest to...
Comments
Be the first to post a comment
Copyright & revisions
Copyright information
- Creative-Commons: The Open University is proud to release this free course under a Creative Commons licence. However, any third-party materials featured within it are used with permission and are not ours to give away. These materials are not subject to the Creative Commons licence. See terms and conditions. Full details can be found in the Acknowledgements section.
Feeds
If you enjoyed this, why not follow a feed to find out when we have new things like it? Choose an RSS feed from the list below. (Don't know what to do with RSS feeds?)
Remember, you can also make your own, personal feed by combining tags from around OpenLearn.
Alternative Formats
Tags, Ratings and Social Bookmarking
Page Tags
Sign in or create a free account to add tags to your personal tag cloud using:
Have you tried our free courses?
Free stuff to your door
Living with Poverty
OU TV & Radio
-
Life In Cold BloodEden
Saturday 0:01 -
Life In Cold BloodEden
Saturday 0:01 -
Bang Goes The Theory s6 in fullEden
Saturday 9:00 -
History Of ScotlandBBC Two
Saturday 10:00 -
Secrets Of Our Living Planet: Emerald BandEden
Saturday 17:00
Views
Votes
Comments
Tags
- climate change (373)
- business (277)
- diaries (194)
- bottom line (169)
- food (168)
- Rough Science (162)
- BBC Two (145)
- internet (145)
- BBC Radio 4 (141)
- BBC (134)
- listings (121)
- Scotland (121)
- points for debate (120)
- children (116)
- Creative Climate (116)
- Bang goes the Theory (116)
- English Civil War (115)
- astronomy (108)
- Thinking Allowed (105)
- religion (98)
- 20th century (94)
- marketing (94)
- Charles I (93)
- communication (92)
- evolution (91)
- sustainability (89)
- research (88)
- architecture (85)
- energy (83)
- nutrition (78)
OpenLearn Links
Copyrighted imageCredit: Background image Lucian Milasan | Dreamstime.com 

