A Gardeners Forum Forums General Discussion The Plants and Flowers Forum Botany 101 Photosynthesis

Notes from my bio class:

-Photosynthesis is the opposite of cellular respiration, and has the reverse chemical equation:
CO2+H2O+light-->C6H12O6+O2
-light has to be specific spectrum (400nm - 700nm)

Here are some major milestones in photosyntheses research:

Helmont (1600s):
-planted willow tree in pot for five years
-found out mass of soil decrease (about 60g) while mas of willow increased dramatically (in kgs)
-inaccurately concluded water was cause of weight increase

Woodward (1600s):
-grew plants for 77 days
-mass of plant increased 1g, while close to 76 000g water used to water plant
-"drawn off and conveyed through the pores of the leaves and exhaled into the atmosphere"

Priestly (1700s):
-mouse in bell cloche; mouse died
-candle in bell cloche and mouse; mouse died faster
-candle with mint plant in bell cloche; could relight candle after ten days bein extinguished
-plants add gas into atmosphere that is used by burning candle and living animals (mice)

Ingenhousz (1700s):
-gas release by plants was oxygen
-inaccurately concluded oxygen (O2) from splitting water (H2O)

Engelmann (1800s):
-placed prism between light and microscope stage (to refract white light so he could see the different colours, full visible spectrum to naked eye)
-lined photosynthetic algae across spectrum and added aerobic bacteria
-bacteria coagulated around algae at red and blue light
-aerobic bacteria seek oxygen; oxygen a product of photosynthesis released bt photosynthesizing algae

van Neil (1900s):
-oxygen produced by plant from slitting water
-used purple sulfur bacteria
-bacteria used hydrogen sulfide and water to produce carbohydrates and water; plants would have used carbon dioxide instead of hydrogen sulfide therefore oxygen from splitting water

Kamen and Ruben (1900s):
-proved oxygen from water
-used carbon dioxide with oxygen isotope 16, and water with oxygen isotope 18
-oxygen produced was oxygen isotope 18 from water

Calvin (1900s):
-discovered Calvin cycle (used to be known as dark reactions)

So, aka me (2020):
-discovered possibility of photosynthesis without light
-discovered possible plants that can thrive on the moon and other planets

There are three types of chlorophyll: chlorophyll a, chlorophyll b,and chlorophyll c.Chlorophyll is the pigment that helps make photosynthesis possible.Chlorophyll can't absorb light in the green spectrum very well which explains why plants ar green.

Just found a mistake: Ingenhousz inaccurately concluded that oxygen was from splitting carbon dioxide CO2

I'd love to hear more about this! Or at least a hint for what kind of search to do to find out more.

lol some bacteria use sulfur in place of water in a similar process like photosynthesis. Photosynthesis (PS) is essentially two cycles: the 'light reactions' and the Calvin cycle. The light reaction produces ATP (adenosine tri phosphate) which is used in the Calvin cycle to produce glucose. To make ATP, electrons need to be displaced (moved through a chain of protein complexes. The light hits a photosystem and bounces from chlorophyll to chlorophyll until it hits the antenna complex where the electrons are) and protons have to be moved. The way to 'excite' these electrons is for a 'photon' of light to hit them and give them enough energy to pass through the protein complexes. So without light, we would need to figure out something to excite these electrons. I'm hoping sound waves maybe? Not very likely as those waves are probably too big and activate something as minute as the electrons. It would also mean that there would be no need for chlorophyll which plants have developed (to a certain have evolved to have...but that's still just theory). Not very likely to have PS without light...photo=light and synthesis=to make. PS= using light to create (in this case glucose). My bio exam is friday...guess I'm done studying lol

Now plants on the moon is much easier. We can have oxygen rich enclosures for human habitation with the plants producing enough oxygen to sustain the enclosure. Most likely, plants will already be thriving when we can live in space. Plants can adapt much easier than humans or any other animal. If you a sun plant in shade, it would grow bigger and darker green leaves to make the most of whatever sun it gets. If you put humans in completely darkness, your pupils will not adjust to allow you to see and there would be no need for eyes (hence certain moles do not have eyes, nor do worms). If we are able to survive in space using carbon dioxide in place of oxygen (hence oxygen being a waste product) we would require plants that can use O2 (our waste) to produce CO2 9what we need). This would throw our whole body off (all our systems that give off CO2...like our carbonic acid <-> CO2 buffer). It's nice to dream lol

HUH? I must admit, I have to constantly refresh my memory concerning most biological processes, and many chemical reactions, etc., but...It seems either an utter impossiblility, or the result of many millions or perhaps a billion years of evolution for humans, or basically any mammal, maybe any animal life, to adapt to breathing carbon dioxide. Most of the information you posted was informative and interesting, but, you'd have to explain further how we could achieve this, I don't see even genetic engineering achieving this result without incredible advances in technology.
I would like to hear any theory that could allow for it, I'm a fanatic (but a little slow, hehe) about science, as well as science fiction.

this sounds a lot like the Krebs cycle to me and I have a mental block about the Krebs cycle and ATP since nursing school.

My final exams are next week and thank God there's nothing on photosynthesis on it...I've probably forgotten everything! Dave, you're absolutely correct. It does take billions of years to evolve to adapt such a process - given the time it took (for those sciency people :P) to go from unicellular organisms in the water to modern complex multicellular organisms. And for all these we've been using O2. we were designed to use O2 and things like hemogoblin would not work with CO2 (though CO does bind and that give your CO poisoning). Could you imagine IF we were able to and have the right technology, how long it'll take before we take over the other planets lol?!!! One thing i'm thinking right now - there's something called a CO2 chamber (which some use to humanely euthanize animals for food for other pets, etc...) build one but with O2 and put a plant inside. Then see how long it takes to wither (when it production of O2 is at a max) and measure the concentration of CO2 and O2. Then take the concentration of O2 in the container as the plant starts to wither, and die. Then do it with CO2 and see how long it takes for the plant to die. Compare that with the rate of a 'normal' human respiring and hopefully figure out a balance between the two. I'm sure if we live on the moon we're probably going to have a little enclosure to live in (like a giant green house lol) and the only source of O2 would be from photoautotrophs.

I'm going to have to read this more carefully.

Kenny, a while back it was all the rage in Hollywood for the stars to use O2 therapy to reduce wrinkles. I remember seeing Kirstie Alley on the Tonight Show holding an O2 tank and blowing it on her face the entire show. She said that O2 fights free radicals and plumps skin. If that's true it seems a plant wouldn't wither at all with the right amount of 02.

Kenny posted info. that was pretty much beyond my understanding, but then, I can be a little daft at times, keep posting, kenny.
I'll point this out, though, plants go through 2 cycles everyday, if I understand it, they take in CO2 during the photosynthetic process, and then go into an "aerobic" cycle when they are without light. I believe all plants have this dual cycle. Maybe kenny will expand on this, I sure can't, without getting out a textbook or Googling.

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