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Meiosis

Interactive Periodic Table

Learn about the periodic table through this interactive game.

The game allows you to explore patterns and trends to understand why the Periodic Table is set out in the way it is.

The periodic table was created by Professor Dmitri Mendeleev in 1869 using the properties of known elements. The Periodic Table organises the elements so that elements with similar properties are in the same column ('Group'), with elements across a row ('Period') shown in order of increasing atomic number. So the Periodic Table links the structure of the atoms of an element with its properties.

Many other interactive periodic tables are available on the web; you can learn more about elements in the Periodic Table in the Visual Elements table from the Royal Society of Chemistry and this photographic one.

Periodic table activity

The interactive Periodic Table helps you learn about elements and their properties in a fun way. The game can be played at a variety of levels of difficulty and in several different ways. It can be played against the clock or competitively by one or more people.

 

Use the information provided to help you place the element in its correct position.

Periodic table activity

The interactive Periodic Table helps you learn about elements and their properties in a fun way. The game can be played at a variety of levels of difficulty and in several different ways. It can be played against the clock or competitively by one or more people.

Use the information provided to help you place the element in its correct position.

Introducing variety

The four haploid daughter cells all contain a different combination of genetic material. This variation is vital to natural selection and survival. There are two main mechanisms that generate this variety:

1. Each cell that forms gametes contains two sets of chromosomes, one originally from the mother and one from the father of the individual. The mixture of these chromosomes that end up in any gamete is completely random. The 23 chromosomes in the gametes can be any mixture, from 23 chromosomes from the mother to all twenty three from the father or any combination – there are 223 or almost eight and a half million possibilities! This is called the independent assortment or random assortment of chromosomes.

2. Crossing over (recombination) takes place during prophase 1 of meiosis, when there are four chromatids lying close together. Large multi-enzyme complexes chop up and rejoin bits of the maternal and paternal chromosomes in a random way. These break points are called chiasmata. They add considerable genetic variation by changing the combination of the alleles on two of the chromatids.

Just a few of the possible combinations of chromosomes that could be found in the haploid daughter cells produced from one original cell

Just a few of the possible combinations of chromosomes that could be found in the haploid daughter cells produced from one original cell

Crossing-over (recombination is another way in which variation is introduced into the haploid daughter cells produced in meiosis.)

Crossing-over (recombination is another way in which variation is introduced into the haploid daughter cells produced in meiosis.)