A Level Biology Revision "DNA and Chromosomes"

You can find all my A Level Biology videos fully indexed at www.freesciencelessons.co.uk/a-level-revision-vide… In this video, we start by looking at how the DNA is arranged in prokaryotes such as bacteria and eukaryotes such as humans. I then describe the structure of chromosomes and explain what is meant by a chromatid. Then I look at homologous chromosomes and explain how these have the same genes but don't always have the same alleles. This video is aimed at the UK A Level Biology specifications. Students studying International A Level Biology will need to check their specification. Image credits: DNA Animation commons.wikimedia.org/wiki/File:DNA_animation.gif brian0918, Public domain, via Wikimedia Commons Cell with chromatin commons.wikimedia.org/wiki/File:Nucleus%26Nucleolu… Source: publications.nigms.nih.gov/insidethecell/chapter1.… Mitochondria commons.wikimedia.org/wiki/File:Mitochondria,_mamm… Louisa Howard Chloroplasts commons.wikimedia.org/wiki/File:Chloroplasts_-_Mic… Juan Carlos Fonseca Mata Chromosome photograph commons.wikimedia.org/wiki/File:Human_karyotype_(2… Doc. RNDr. Josef Reischig, CSc.

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