November 10, 2024
Biology A Level

Biology A Level “DNA and Chromosomes”

Author: Freesciencelessons via YouTube
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Biology A Level

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.

Image credits:

DNA Animation
https://commons.wikimedia.org/wiki/File:DNA_animation.gif
brian0918, Public domain, via Wikimedia Commons

Cell with chromatin
https://commons.wikimedia.org/wiki/File:Nucleus%26Nucleolus.gif
Source: http://publications.nigms.nih.gov/insidethecell/chapter1.html

Mitochondria
https://commons.wikimedia.org/wiki/File:Mitochondria,_mammalian_lung_-_TEM.jpg
Louisa Howard

Chloroplasts
https://commons.wikimedia.org/wiki/File:Chloroplasts_-_Microscopic_view_of_Elodea_canadensis.jpg
Juan Carlos Fonseca Mata

Chromosome photograph
https://commons.wikimedia.org/wiki/File:Human_karyotype_(263_17)_Karyotype_Human,_45,XY_t13-14.jpg
Doc. RNDr. Josef Reischig, CSc.

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