Uploaded October 2024 | Updated September 2026, 1 hour ago
In this video, we look at the control of insulin secretion by beta cells in the pancreas. We look at how the beta cells respond to an increase in the blood glucose concentration by secreting insulin. This involves the role of potassium channels and calcium channels and how they lead to exocytosis of insulin.
Image credits:
Spaghetti
commons.wikimedia.org/wiki/File:Natto_spaghetti_001.jpg
Ocdp, CC0, via Wikimedia Commons
In this video, we look at the control of insulin secretion by beta cells in the pancreas. We look at how the beta cells respond to an increase in the blood glucose concentration by secreting insulin. This involves the role of potassium channels and calcium channels and how they lead to exocytosis of insulin.
Image credits:
Spaghetti
commons.wikimedia.org/wiki/File:Natto_spaghetti_001.jpg
Ocdp, CC0, via Wikimedia Commons
![GCSE Chemistry Revision Development of the Periodic Table
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In this video, we look at the development of the periodic table. First we look at what is meant by groups in the periodic table and why the periodic table is called periodic. We then look at how the scientists Döbereiner and Newlands made early attempts to categorise elements and why these were not successful. You are not expected to learn the work of these scientists but you could be provided with information about them in the exam and asked questions on them. We then look at the scientist Dmitri Mendeleev. We see how he produced a successful periodic table by arranging the elements by atomic weight. We look at how he switched the order of elements when required and left gaps for undiscovered elements. We finish by looking at how the modern periodic table arranges the elements by atomic number and how this solves the problem of elements being in the wrong order.
This video is based on the AQA spec. This video may be appropriate for iGCSE / O Level Chemistry. Please consult your specification. The Amazon link above is an affiliate link. This provides a small commission which helps to support freesciencelessons. The cost remains the same to you. If you prefer not to use this, you can search Amazon for the Freesciencelessons workbooks.
Image credits:
Dobereiner https://commons.wikimedia.org/wiki/File:Johann_Wolfgang_D%C3%B6bereiner.jpg
By Carl August Schwerdgeburth, 1785-1878 (engraver), and Fritz Ries, 1826-1857 (painter) [Public domain], via Wikimedia Commons
Newlands https://commons.wikimedia.org/wiki/File:John_Alexander_Reina_Newlands.jpg
By The original uploader was DALIBRI at German Wikipedia. (Transferred from de.wikipedia to Commons.) [Public domain], via Wikimedia Commons
Mendeleev https://commons.wikimedia.org/wiki/File:Mendeleev_c1880.jpg
See page for author [Public domain], via Wikimedia Commons GCSE Chemistry Revision Development of the Periodic Table](https://i.ytimg.com/vi/IoldeyRWgz8/mqdefault.jpg)




![GCSE Biology Revision Microscopy
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In this video, we look at microscopes. First we explain the advantages of an electron microscope over a light microscope and then we learn how to carry out calculations based on magnification.
This video is based on the AQA spec. This video may be appropriate for iGCSE / O Level Biology. Please consult your specification. The Amazon link above is an affiliate link. This provides a small commission which helps to support freesciencelessons. The cost remains the same to you. If you prefer not to use this, you can search Amazon for the Freesciencelessons workbooks.
Image credits:
Light microscope By Kitmondo Marketplace - Olympus BH-2 BHT Trinocular Laboratory Microscope, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=50226403
Leewanhoek microscope By Jeroen Rouwkema, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=3657142
Electron microscope By Cjp24 - Own work, GFDL, https://commons.wikimedia.org/w/index.php?curid=13317336
Fibroblast By SubtleGuest - slika uzeta sa engl. vikipedije [1], CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=2903074
Nucleus Public Domain, https://commons.wikimedia.org/w/index.php?curid=3266416
Ruler By Luigi Chiesa - Photo taken by Luigi Chiesa, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=1137573
Cheek cells
https://commons.wikimedia.org/wiki/File:Cheekcells_stained.jpg
Mulletsrokk, CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons GCSE Biology Revision Microscopy](https://i.ytimg.com/vi/L5StAE_uuxM/mqdefault.jpg)




