Debate and discussion of any biological questions not pertaining to a particular topic.
I was reading my lab manual, and it says "All living organisms, including protists, bacteria, and plants, create ATP in fermentation or cellular respiration and then use ATP in metabolism."
It doesn't go into any more detail than that, it just states it like it's a known fact and then moves on. But I was like... I had no idea that plants used fermentation or cellular resp., I thought they just got all their energy from photosynthesis. :/
So, since I'm pretty sure they don't use cellular resp., does anyone know what kind of fermentation they use? Do they use it all the time, or just when they don't have access to light?
PS. now that I think about it, there are some plants like the Venus Flytrap that seem to ingest organic material. So do they use cellular respiration?
Plants use photosynthesis to make sugars out of water, CO2 and sunlight. But a plant cell (like any other cell) cannot use sugars for their cellular processes, it needs to break down the sugars and make ATP. Basically, the only difference between humans and plants in this chapter is that plants make their own sugars, while we get ours from food. But we still both need to use those sugars, and we do that through cellular respiration.
Fermentation is strictly defined as any way of anaerobically degrade pyruvic acid and recycle NAD+ to keep glycolysis going. You can then categorize this process as lactic acid fermentation (where pyruvate accepts electrons from NADH directly and becomes lactate), alcoholic fermentation (where pyruvate is first decarboxylated to acetaldehyde which then accepts electrons from NADH to become ethanol) and others (which are much more obscure). So technically, human cells are able to carry out lactic acid fermentation. Liver cells also have the enzyme alcohol dehydrogenase (responsible for ethanol formation in yeast and other fungi), but we use it in the reverse direction so to speak to get rid of any alcohol which we consume by converting it to pyruvate.
Plants however, can carry out alcoholic fermatation. They don't normally do it, because plants are usually in contact with oxygen. However, if you flood the root of a plant for about a week the cells are starved of oxygen, and because of this they will start carrying out alcoholic fermentation to survive.
"As a biologist, I firmly believe that when you're dead, you're dead. Except for what you live behind in history. That's the only afterlife" - J. Craig Venter
that is what my bio textbook says.
just to complete the last part
in alcoholic pathway ethanol forms a waste while the lactate formed in the lactate pathway can be broken down further. that is what leads to the oxygen debt
it isn't what you do that matters but it is how you do it