Relative sizes of neurotransmitters and neurons.
Hunger, satiation Two thermostats, one to start eating, one to stop eating.
But… How do the hormones translate to action?
Low blood sugar. Desire is created. Activity engaged.
amino acid peptide polypeptide protein folding amino acid side chain amino acid peptide protein https://www.google.com/search?q=amino+acid+peptide+protein&oq=amino+acid+peptide+protein&aqs=chrome..69i57j0l3.7404j0j7&client=ms-android-google&sourceid=chrome-mobile&ie=UTF-8#sbfbu=0&pi=amino%20acid%20peptide%20protein
Peptide - Wikipedia https://en.wikipedia.org/wiki/Peptide
How enzymes work https://youtu.be/yk14dOOvwMk
Khan Academy: Oxidation and Reduction from Biology point of view https://www.khanacademy.org/science/biology/cellular-respiration-and-fermentation/intro-to-cellular-respiration/v/oxidation-and-reduction-from-biological-view?utm_source=YT&utm_medium=Desc&utm_campaign=biology
OIL RIG
reaction equation
$$\require{mhchem}$$
$$\ce{2H2(g) + O2(g) -> 2H2O + \text{heat}}$$
combustion reaction
Oxidation in chemistry, biochemistry, cellular respiration
\begin{align} \text{glucose + oxygen} &-> \text{carbon dioxide + water + energy}\\ \ce{C6H12O6 (aq) + 6O2 &-> 6CO2 + 6H2O + 38 ATP}\\ \ce{C6H12O6(aq)} &= \text{glucose in aqueous solution}\\ \ce{O2} &= \text{oxygen}\\ \ce{CO2} &= \text{carbon dioxide}\\ \ce{H2O} &= \text{water}\\ \ce{C10H16N5O13P3} &= \text{Adenosine Triphosphate (ATP)}\\ \end{align}
1 mole of glucose in aqueous solution
plus 6 moles of oxygen
yields 6 moles of carbon dioxide
plus 6 moles of water
plus 38 ATPs
Khan Academy: Photosynthesis https://www.khanacademy.org/science/ap-biology/cellular-energetics/photosynthesis/v/photosynthesis#:~:text=Photosynthesis%20is%20usually%20represented%20by,Created%20by%20Sal%20Khan.
\begin{align} \text{carbon dioxide + water + sunlight} &-> \text{carbohydrate + oxygen}\\ \ce{CO2 + H2O} + \text{photons} &-> \ce{CH2O + O2}\\ \end{align}
Bozeman Science: Photosynthesis and respiration https://www.youtube.com/watch?v=0IJMRsTcwcg
10:41 line graph of atmosphere $\ce{O2}$ contents