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1answer
48 views

Do all prokaryotes have ATP synthases and an electron transport chain?

I was looking this up and I'm wondering if so far I'm correct about the following: For the most part eukaryotes do aerobic respiration, which involves glycolysis, the Krebs cycle and oxidative ...
1
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0answers
15 views

Mechanism behind energy generation

I recently read about methanogens and methanotrophs. One converts CO2 to methane and vice versa respectively. I can't get exact mechanism for the methanotrophs and I know they can't be reversed ...
2
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1answer
41 views

How many calories do gut bacteria burn?

It has become well-accepted that microbiota of the gut (a.k.a. gut bacteria) consume calories that are ingested and can have significant effects on energy metabolism in humans. For example, if you ...
1
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1answer
29 views

Conversion of ATP to NADH without creating a proton motive force?

Is it possible to convert ATP into NADH and vice versa without first creating a proton motive force? If so by what mechanism is it done?
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0answers
47 views

In glycolysis, what is the source of the electron that makes NAD+ into NADH instead of NADH+? [closed]

I looked at the formula for the glycolysis reaction. The overall reaction seems balanced, however, I don't see anything on the left hand side of the equation that would provides the electron to ...
2
votes
2answers
72 views

What are the known energy capturing processes in biological systems?

I am not a biologist. I am aware that photosynthesis is the main process for capturing electromagnetic energy from the Sun. Also, I am aware that some bacteria can capture energy from boiling water ...
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0answers
23 views

What are the metabolic consequences of negative mechanical work in muscle contractions?

When a muscle contracts while it shortens (concentric), it consumes ATP I believe primarily due to cross-bridge shortening to remove the myosin head from it's attached state. However, when a muscle ...
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0answers
27 views

Is there any evidence to suggest that exercise reduces the side effects of caffeine?

I heard a friend say: I'm not drinking coffee this week. My body can only process the caffeine if I run at least 15km a week. I found this claim fascinating - that exercise temporarily ...
2
votes
1answer
285 views

Why do mice have a higher metabolism?

Mice and other small animals have higher metabolic rate than humans. How does that happen on cellular level, if we look on one cell in the mouse body? What is it in this cell that will be ...
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1answer
38 views

ATP yield of fermentation: study to cite?

Everywhere I find the ATP yields of respiratory and fermentative metabolism of glycolysis. While that of oxidative phosphorilation I could find in Stryer to cite one study where this was addressed ...
2
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1answer
65 views

Metabolic efficiency for fats and sugars

I am making an exercise for physics students about the first law of thermodynamics, burning heat and evaporation heat. So my idea is to use cycler which runs on fats and sugars where proportion ...
2
votes
1answer
84 views

Which step in endocytosis requires ATP?

Everybody seems to agree that endocytosis is an energy-using process, and as such requires ATP hydrolysis. However, which particular step requires it? More precisely, which 'molecular machine' ...
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2answers
590 views

Does ATP hydrolysis reaction have a high or low activation energy?

I was recently studying about ATP and how it functions as an energy carrier to all biological processes; however, I came across a confusing and paradoxical statement from two sources: (at 7:36) and ...
3
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2answers
67 views

Determining how much energy a plant takes in?

I asked a question on WorldBuilding.SE, "Are diamond berries possible?". This led to asking a question on Chemistry.SE about the amount of energy required to burn a 1 ct. diamond (−6.527kJ). The ...
5
votes
2answers
170 views

Energy transformations in chemiosmosis and ATP synthase

In terms of energy, how does chemiosmosis drive ATP synthase? How does electrical energy turn into mechanical energy and then into chemical energy? Would the movement of $H^+$ be considered passive ...
2
votes
3answers
120 views

Does the biosphere have infinite resources and are they infinitely renewable?

Does biomass represent all of the resources of the biosphere and therefore it would be theoretically infinitely renewable (as long as we have the sun) since all the biomass is part of the carbon ...
0
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0answers
39 views

Cell energy consumption and food intake

I am wondering if each cell in human body starts consuming ten percent more energy, how much food one has to consume compared to normal intake?
0
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1answer
41 views

Energy consumption of a resting synapse

What is the energy penalty of maintaining rarely used synapse? I'm wondering if forgetting is cheaper than remembering unnecessary details.
0
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1answer
31 views

Beta oxidation of saturated fats

In my text book there is an example of a 18 carbon long fat and it says that it can run 8 laps of oxidation. I don't understand why it doesn't run 9? 2 are removed each cycle? Thanks.
4
votes
1answer
65 views

NADH shuttles - Why cytosol?

Why is the malate-aspartate and the glycerol-3-phosphate shuttles located in the cytosol and intermembrane space? The krebs cycle happens in the matrix so why wouldn't they push electrons from the ...
11
votes
1answer
378 views

Is there a significant difference in sedentary calorie-burn between a thinker and non-thinker?

I've read that, on average, a sedentary female burns between 1,600 - 2,000 calories and a sedentary male burns between 2,000 and 2,500 calories. I've also read that the brain itself burns quite a few ...
1
vote
1answer
52 views

Mitochondria variability per tissue in humans?

I would like to know the distribution of mitochondrial content per tissue type in humans. I understand the simple metric that energetically active or energy requiring tissues will have more ...
1
vote
1answer
155 views

What is the role of Aspartate Transaminase in gluconeogenesis?

I know that oxaloacetate cannot cross the mitochondrial membrane, but can instead be converted to aspartate, shuttled out, and then re-converted back to oxaloacetate. What does this have to do with ...
3
votes
3answers
456 views

Kinetic Vs Potential Energy in Biochemical Contexts

This question is causing great confusion in my head. Which of the following is an example of potential rather than kinetic energy? A) the muscle contractions of a person mowing grass B) water ...
3
votes
2answers
8k views

What causes muscles to generate heat on contraction?

I'm curious what the exact cause is of dramatic heat generation that comes along with muscle activity. Can anybody explain this in understandable language?
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0answers
81 views

What is the biological basis of “energy” that extraverted humans draw from social engagements and introverts expend?

This question is related to this question about introverts becoming exhausted after extended social events on cognitive sciences stack exchange. As I read more on the topic of human ...
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votes
6answers
2k views

Can we harvest energy from plants?

This is a cross-cutting question but I think its core is about biology. Our society's need for energy is dramatically growing and we are messing up with our environment to answer them. Maybe another ...
5
votes
2answers
151 views

Why does caffeine give you so much energy, while being so low on calories?

There's definitely something I'm missing here. Since calories is a unit of measurement for energy, and caffeine seemingly gives you a lot, how can the labels on caffeinated products have such a low ...
3
votes
2answers
153 views

Tracking of oxygen molecules in glucose oxidation

For this reaction, found in typical biochemistry textbook: $C_6H_{12}O_6 + 6O_2 \to 6CO_2 + 6H_2O$ I am interested in where do the oxygen atoms of $6O_2$ go. I think they go to $6H_2O$, but this is ...
5
votes
2answers
151 views

Burning fat transferred from one part of the body to another

While doing some research on cosmetic surgery, I discovered that there are several ways of doing breast enhancements, one of which was using body fat. While I haven't researched this method, I assume ...
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2answers
276 views

Organisms using thermal energy as their sole energy source

After seeing this question I remembered that in secondary school we watched a documentary stating something along the lines of "all organisms derive their energy directly or indirectly from the sun. ...
2
votes
0answers
50 views

Is body energy production and consumption cyclical?

If we look into how energy is produced by the humans, it always involves some kind of periodicity: fuel combustion rotates engines, water rotates turbines, nuclear chain reactions heat up water, which ...
2
votes
1answer
201 views

How does the human body use energy?

As far as I know the glucose gets processed from carbs and fats and as a result carbon dioxide, water and "energy" are released. The carbon dioxide and water are expelled by the body, and then energy ...
6
votes
2answers
355 views

How efficient is the human body at metabolizing food?

My friend and I were having a discussion over how "efficient" human digestion is. If a human ate a 1000 calorie hamburger, how many of those calories (how much energy) does the body process into ...
1
vote
1answer
198 views

Calories burn rate calculation — scientific studies

There are many online calculators for measuring walking/running/bicycling calories burn rate. They differ in input parameters like some might need my weight as well as height and some don't. Almost ...
4
votes
2answers
300 views

Breakdown of energy expenditure at the level of a single cell

The metabolic rate measures how much energy an organism expends over a unit of time. Its breakdown for the human body in terms of its functions is well documented : so much for the heart, for the ...
4
votes
1answer
104 views

Do mitochondria use ATP in order make another ATP from glucose?

Do mitochondria use ATP in order make another ATP from glucose, or does it use another source of energy to convert glucose to ATP?
2
votes
2answers
239 views

How can toddlers expend seemingly boundless energy when they eat so little?

A toddler's food intake seems very little: only milk and water and some solid food. Therefore, from where does this energy come?
1
vote
1answer
99 views

Could the Warburg effect be used to starve cancer cells in situ?

What is wrong with the following chain of reasoning? Nearly all cancer cells rely on high rates of glucose uptake (upto 200 times more than normal cells). This is known as the the Warburg effect. ...
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vote
2answers
92 views

Can viruses be used to extract oil from algae?

I read that one hard step in algae oil extraction is to rupture (or fracture) the cell walls to get the contents inside. Some people use chemical methods; some use sonication or mechanical forces. I ...
3
votes
1answer
146 views

Is there a way to measure ATP usage in the brain similarly to fMRI?

Is there a way to measure ATP usage in the brain (or anywhere else) similarly to how fMRI works (measuring changes in iron resonance in oxygenated/deoxygenated blood)? Is there some sort of similar ...
1
vote
1answer
638 views

Question regarding Rate of Photosynthesis AP Biology Lab

We are doing a lab on the effects of light intensity/wavelength on the rate of photosynthesis in AP bio and we were asked to visit this website here: ...
1
vote
1answer
54 views

What is the energy source for adipocytes?

Since adipocytes export fatty acids and glycerol and don't use them as an energy source, what is the main source of energy for adipocytes?
4
votes
1answer
394 views

Saltatory conduction of nerve impulses

I am aware about some basics of saltatory conduction of nerve impulses. I know that the nerve impulses (ion flow and the depolarization) are transferred from node to node in myelinated nerve fibers. ...
4
votes
1answer
250 views

Does the body lose energy or gain energy relatively when drinking or eating hot things?

Does the body lose or gain energy when drinking or eating hot things compared to more neutral temperature things? On the one hand, The body could somehow convert the heat energy into human usable ...
3
votes
1answer
111 views

Can cats use ketone bodies as only source of energy?

I recall reading that much of the energy a cat produces from its food comes from proteins which I assume would produce energy via being catabolised into amino acids which in turn, if glucogenic, would ...
0
votes
2answers
64 views

3 fates of this matter

When an animal eats something, it obtains matter and energy right? But, what are the 3 possible fates of the matter and 3 possible fates energy. I don't understand what they are even asking. What ...
5
votes
1answer
259 views

Are the brains of any herbivorous animals capable of utilising ketone bodies as an energy source?

I ask this question because earlier today I heard from a lecturer at my university that a sheep's brain cannot utilise ketone bodies as an energy source and hence with insufficient glucose supply for ...
3
votes
2answers
1k views

Can any one reaction in a cell be at equilibrium?

I know that metabolism as a whole can never be at equilibrium (otherwise the cell is dead !) but I wonder whether a few reactions in the cell could be at chemical equilibrium at a given point of ...
3
votes
1answer
1k views

Why do brain cells use shuttles that pass electrons from NADH to FAD?

Brain cells are cells require one of the highest amount of energy of any cell of body. So why do they use a shuttle which will transfer electrons from NADH produced in glycolysis to FAD(and there by ...