Questions

Hello guys,

I just had a few questions to ask regarding bacteria's production of glucose and bacteria that use chemosynthesis to make energy.

1. Can you tell me why bacteria produces glucose in its cytoplasm?
Is it because they don't have no cell membrane or mitochondria?

2. Can you please give me an example of a chemosynthetic bacteria?
Is nitrogen bacteria an example of one, but they do not make energy for themselves, they make it for the plants?

1. Exactly! Bacteria don't have a mitochondrion (as our mitochondria evolved from bacteria that infected our cells, so far too big to infect other bacteria!), so all glycogenesis is cytoasmic.

2. Not too sure about this one, soz!

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Thanks a lot ! Also, by the last part of your sentence glycogenesis is cytoasmic, do you mean that glucose is always made in the cytoplasm?
Also, did you say that because only plants or other living organisms such as bacteria can actually produce glucose as a byproduct of photosynthesis?
Because, humans don't actually make glucose, they just break the carbohydrates down into glucose in the small intestine. Some of the glucose is also converted into glycogen and stored in the liver.
Also, does this relate to 'glycogenesis' as I suppose, that 'glycogenesis' is the formation of glycogen from sugars.

I'm not sure if I'm actually correct :/

You're absolutely right, my friend. Glycogenesis is the wrong term for me to use, and you've defined it accurately. What I meant was gluconeogenesis, which is the formation of new molecules of glucose (sugar).

In bacteria, gluconeogenesis takes place in the cytoplasm. In most lifeforms, this is the case, but there's also some gluconeogenesis within mitochondria in animals and plants (but it's mainly cytosolic). The reason that it happens in the cytosol in bacteria is simply because there's no other place for it to happen! You're right that plants mainly produce their glucose by photosynthesis (which occurs in the chloroplasts). This is a good learning point: the different domains of life (animal, plant, bacteria, fungi ... ) tend to behave very differently biochemically. Hence why we see this big difference in how cells acquire glucose and produce usable energy!

Bear in mind that humans do produce their own glucose! I'd advise you look up "gluconeogenesis" - most of this happens in our liver, and to a lesser extent, our kidneys. While our main source of glucose is from eating (bacteria also mainly get their glucose from "eating" the sugars in their environment), during periods of fasting, humans are capable of producing our own glucose.

So basically, gluconeogenesis is the formation of glucose from noncarbohydrate sources such as amino acids and glycerol.
So plants, animals and bacteria all undergo gluconeogenesis. But, sometimes plants and animals may go through this process in the mitochondria instead of the cytoplasm. On the other hand, bacteria do not have any membrane bound organelles which is why they only undergo gluconeogenesis in their cytoplasm.

Plants usually produce glucose using photosynthesis and humans get their glucose and sugars from carbohydrates when eating food.

When humans are fasting and plants do not receive enough light energy or oxygen e.g. at night, do the amino acids and glycerol just make glucose?

Also, where is glycerol actually stored in the body? Is it true that fatty acids and glycerol are converted into triacylglycerols?

Correct me if I'm wrong please. Sorry, everytime, I just repeat what you tell me - but I'm trying to make sure that I understand it .

Exactly right, it's important to note that plants get the fuels for gluconeogenesis mainly through nitrates in the ground (which they usually use to make proteins).

Glycerol is stored in animals as fat. Glycerol + 3 fatty acids = triglycerides/triacylglycerols, whatever you want to call it.