cellular respiration

[bionewbie]

Hi, I'm new at this fourm and this is my first year taking biology in highschool so I don't have much background biology knowledge. I had a test on cellular respiration last week and I've done badly. I was wondering if anyone can provide me with a good answer on one of my test questions so I'll know how to answer questions similar to it next time on a test. Thanks!

Question:
a) Under what conditions would some cells in the body produce the least amount of ATP and why?
b) Which cells are those?

[biostudent84]

Heya!

Think of ATP as gasoline. When it turns into ADP, energy is released. Just think about which cells NEED the least amount of energy. My professor was fond of saying it was the skin cells on the middle of your back. They don't do much, they just sit there...therefore they don't need to make much energy so they don't.

Hope this helps.

[CIC Lafayette]

Hi. Im also new to this forum. first of all, I am also studying photosynthesis, and cellular respiration. I'm studying for a test, and im pretty sure i know all of it. So what grade are you guys in? how often do you get on? Ill be here once in a while, when i happen to not comprehend some concepts or when the teacher tells us that a test is imminent to be given.

[CIC Lafayette]

SO, ill start with glycolysis. what is that exactly? a pathway...??? and what is the difference between anarobic and aerobic respiration? aerobic respiration uses oxygen, and the other dosent, but i don't get why both exist in the first place. organic compunds go into glycolysis, all of a sudden, oxygen is either present or not. I don't get that.

[CIC Lafayette]

by the way, I believe ATP is created least when the season changes into fall or winter. less and less resources are present and therefore, less products are created, like less dough, less bread. sorry, thought that i state my opinion.

[biostudent84]

Glycosis is what my ecology professor calls "The Big Lie"

You are used to seeing this formula:
C H O + ADP ==> ATP + CO
6 12 6 2

The actual chemical processes that is involved to get from one side to the other of that reaction literally fills a book. It is done through a process called the Kreb's Cycle.

In plants, yes, less ATP is created during the winter. Most glucose in plants is derived from photosynthesis. During the winter, no photosynthesis takes place. Keeping photosynthetic organs (leaves) alive costs energy. In wintertime, that energy cost is greater than the energy benefit that would come from photosynthesis.

it really is a game of survival, and there are many different tactics to "win."


For the ATP, and how it works with or without oxygen, check this tutorial:

http://www.biology-online.org/1/3_respiration.htm

Anaerobic respiration occurs in humans usually when there is very little motion. Hold up a book in the air perfectly still. Hurts after a while, doesn't it? That is a byproduct of anaerobic respiration, lactic acid.

[MrMistery]

Hi, i wouldn't like to contradict Kyle since I saw he knows just about everything on anything. But, what I know differs a little. During an intense physical efort when not enough oxigen can be transported to the muscles the Krebs cycle can not take place(it requires oxigen). However, the muscles do not stop contracting. They keep producing energy(with much less efficency though) through a process called lactic fermentation. The product of this process is lactic acid wihch, if you do not stop activity, over time, accumulatesin the muscles causing muscular cramps
I believe this is the time cells produce the least amount of energy possible, since it is not the usual aerob respiration of the cell, but an anaerob respiration

[mith]

Also like to add that you produce much less atp in the fermentation cycle, and your cells may not have the energy to sustain the effort.

[Rainman600]

During an intense physical effort when not enough oxygen can be transported to the muscles the Krebs cycle can not take place(it requires oxigen). However, the muscles do not stop contracting. They keep producing energy(with much less efficency though) through a process called lactic fermentation... I believe this is the time cells produce the least amount of energy possible..

I would agree with this!

[MrMistery]

I didn't write the numbers because i wasn't sure but i've checked my textbooks and I new correctly. The amount of energy produced by muscles through lactic fermentation from one molecule of glucose is between 16-30kcal, opposed to 675kcal in normal cellular respiration(686 in some books ) The difference is obvious

[Nick]

I didn't write the numbers because i wasn't sure but i've checked my textbooks and I new correctly. The amount of energy produced by muscles through lactic fermentation from one molecule of glucose is between 16-30kcal, opposed to 675kcal in normal cellular respiration(686 in some books ) The difference is obvious

Yeh in molecules its probably better to say in anaerboic repiration that it makes 2 energy molecules of ATP where as the aerobic respiration makes 36-38 energy molecules of ATP

[MrMistery]

Yes, you could say that, but there is something worth saying
The hydrolysis of an ATP molecule gives you 7.3 kcal. If you multiply that by 36(38 in some books) you do not get 675 kcal. Where did the rest of the energy go? It was lost through heat. Only 40% of the energyfrom one molecule of glucose is converted into ATP- the rest, as I said, is lost through heat.
It isn't written anywhere if the precentege applies at the fermentation but 7.3 times 2 is not 30 so...