how do Yeast undergo Cellular Resp. with no sugar

[somerandomguy]

Ok, so i'm doing a lab right now to see how the amounts of sugar affect yeast activity. We have equal amounts of water and yeast in 5 test tubes. Each of the 5 test tubes get diff amounts of sugar: one with no sugar, one with 1 g, and another with 2 g, and another with 4 g, and the last one having 8 g. I understand that the yeast in the tubes with sugar went thru cellular resp so that's why it gave off co2. But the one with no sugar still produced 21 mm of bubbles. Why did that happen? Isn't it impossible to go thru cellular resp without glucose? Did it produce co2/o2 in another way? Also, we used sink water instead of distilled water so i'm not sure if that matters or not.

Edited November 17, 2017 by somerandomguy

[fiveworlds]

What was the results after you left the yeast for a while? I would imagine that yeast can probably store a form of glucose and so respiration will continue for a short while.

[Paul Atreides]

Yeast do indeed store energy in a similar way to other fungi as well as plants. They have food vacuoles that store oils and the sugar glucose in the form of glycogen that can be hydrolysed when needed. It is indeed impossible for yeast to respire without an energy source, let alone any other organism, but if they have stored energy then it is possible. Lastly, using sink water wouldn't matter that much unless you have a very shady water company that pumps water to users with glucose dissolved. Tap water generally contains ions or very small amounts of disinfectants which are not of great use energy-consumption wise to many organisms, and in fact some solutes in tap water can even be toxic to micro-organisms such as chlorine or chloride. I hope this answers your question.

[dylrovertson]

On 12/16/2017 at 4:17 PM, Paul Atreides said:

Yeast do indeed store energy in a similar way to other fungi as well as plants. They have food vacuoles that store oils and the sugar glucose in the form of glycogen that can be hydrolysed when needed. It is indeed impossible for yeast to respire without an energy source, let alone any other organism, but if they have stored energy then it is possible. Lastly, using sink water wouldn't matter that much unless you have a very shady water company that pumps water to users with glucose dissolved. Tap water generally contains ions or very small amounts of disinfectants which are not of great use energy-consumption wise to many organisms, and in fact some solutes in tap water can even be toxic to micro-organisms such as chlorine or chloride. I hope this answers your question.

but ye its largely focused on unit 2 and prokaryotes and eukaryotes also know photosynthesis equation and cellular resp equation annnd like cohesion adhesion covalent hypertonic hypotonic ionic h+ ions