Uploaded January 2025 | Updated September 2026, 6 hours ago
In this video, we look at RNA interference by siRNA and miRNA. First we recap the structure of RNA. We then look at how the level of a specific protein can be regulated by siRNA, including the roles of Dicer and the RISC. We then explore RNA interference by miRNA.
Image credits:
Human chromosomes
commons.wikimedia.org/wiki/File:Human_karyotype_(263_17)_Karyotype_Human,_45,XY_t13-14.jpg
Doc. RNDr. Josef Reischig, CSc., CC BY-SA 3.0 creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons
In this video, we look at RNA interference by siRNA and miRNA. First we recap the structure of RNA. We then look at how the level of a specific protein can be regulated by siRNA, including the roles of Dicer and the RISC. We then explore RNA interference by miRNA.
Image credits:
Human chromosomes
commons.wikimedia.org/wiki/File:Human_karyotype_(263_17)_Karyotype_Human,_45,XY_t13-14.jpg
Doc. RNDr. Josef Reischig, CSc., CC BY-SA 3.0 creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons








![A Level Biology Revision (Year 13) Excretion and Waste Products
In this video, we look at excretion and waste products. First we look at the definition of excretion. We then look at the waste products carbon dioxide, nitrogenous waste products including urea and bile pigments.
Image credits:
Tiger
https://commons.wikimedia.org/wiki/File:Siberischer_tiger_de.jpg
S. Taheri, CC BY-SA 2.5 https://creativecommons.org/licenses/by-sa/2.5, via Wikimedia Commons
Fish
https://commons.wikimedia.org/wiki/File:Vieja_melanura Karlsruhe_Zoo_01.jpg
H. Zell, CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons
Bird
https://commons.wikimedia.org/wiki/File:Female_house_sparrow_at_Kodai.jpg
Deepak Sundar, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons
Insect
https://commons.wikimedia.org/wiki/File:Sympetrum_sanguineum_qtl13.jpg
Quartl, CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons
Red blood cells
https://commons.wikimedia.org/wiki/File:Blood-rbcs_and_thrombocytes2.jpg
Echinaceapallida, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons
Liver animation
https://commons.wikimedia.org/wiki/File:Liver_01_animation2.gif
Polygon data is generated by Database Center for Life Science(DBCLS)[2], CC BY-SA 2.1 JP https://creativecommons.org/licenses/by-sa/2.1/jp/deed.en, via Wikimedia Commons A Level Biology Revision (Year 13) Excretion and Waste Products](https://i.ytimg.com/vi/iYtgn7dwGW0/mqdefault.jpg)

