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Questions tagged [energy]

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16
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3answers
17k views

Does any organism use both photosynthesis and respiration?

Chlorophyll and hemoglobin are very similar molecules, as far as I understand. The important difference being one using an iron atom and the other a magnesium atom. Do any organisms use both to get ...
10
votes
1answer
851 views

What bacteria shed harvestable energy from root zone organic matter?

I recently heard of a successful effort that harvests energy from soil at plants' bases due to apparently bacterial breakdown of wastes from the plants: Via photosynthesis a plant produces organic ...
9
votes
3answers
887 views

Why do (almost) all energy carriers contain adenine?

Unlike this question which is specific to just ATP, this one includes all energy carriers. When thinking of common energy carrying molecules, I can think of Adenosine triphosphate (ATP), Nicotinamide ...
9
votes
1answer
17k views

Why is ATP produced in photosynthesis used to synthesize glucose?

In photosynthesis ATP is produced in light-dependent reactions only to go to the Calvin cycle to be turned into glucose to make ATP during respiration: Why isn't this ATP just directly released into ...
6
votes
1answer
2k views

If oxygen is such a good energy source, why do plants release it?

Why do plants release excess oxygen, rather than consuming it entirely given it is an excellent energy source?
6
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3answers
2k views

The effect of depth on net primary production in aquatic ecosystems

The figure shows the relationship between the water depth and net primary production (=P-R). I want to know why the production (P) initially increases with water depth near the surface? I have seen ...
6
votes
1answer
1k views

Why do we get tired [closed]

At the end of a day full of work, it is general for people that their eyelids start to feel heavy. Laziness takes over and we begin to yawn. We all know that we're tired at that time, but why people ...
5
votes
2answers
13k views

Does endo- and (or) exocytosis require energy? Do they belong to active / passive transport?

I expect vesicle formation and fusion to require energy input; however, I'm not sure about which of endocytosis and exocytosis require energy and how they use the energy input. Do they belong to ...
5
votes
1answer
70 views

What is meant by increase in information embodied in the system?

From Ecosystem Ecology edited by Sven Erik Jørgensen After the initial capture of energy across a boundary, ecosystem growth and development is possible by an increae of the physical ...
5
votes
2answers
101 views

Does food really give our bodies the energies that we have determined by burning them in the lab?

You are likely to have come across numbers like sugars 17kJ/g (4kcal/g) as the energy supposedly available to our bodies after eating. Yet these values have been determined using very artificial means,...
4
votes
1answer
3k views

What is the brain's preferred energy source? Glucose or ketones?

As with all cells in our body, I know that the brain can get fed from both glucose and ketones, so my question is, given both of them, which one would the brain prefer to utilize first?
4
votes
2answers
104 views

Is it a valid generalization that kinases catalyse reactions involving energy transfer and utilization?

The Wikipedia entry for kinase states that "a kinase is an enzyme that catalyzes the transfer of phosphate groups from high-energy, phosphate-donating molecules [such as ATP] to specific substrates". ...
4
votes
2answers
323 views

Evidence that Attention Deficit Hyperactivity Disorder (ADHD) is caused by too much cellular ATP?

The question is pretty simple — it's just a theory that I remember my biology teacher mentioned long ago and for years now I've wondered about it without ever asking. Some people with attention ...
4
votes
2answers
644 views

Glycolytic non-oxidative pathway

I am currently digging in some books to understand the three major metabolic pathways involved in physical training. The most difficult one for me is the glycolytic non-oxidative pathway (also more ...
4
votes
2answers
1k views

What does “energy transfer in cells” mean?

"ADP and ATP are involved in energy transfer in cells." I know what is ATP and I know how ADP is formed, but I don’t understand what “energy transfer in cells” means.
4
votes
1answer
510 views

Why cannot machines use energy stored in a way similar to biological systems' energy storage?

Owing to the generality of the question I am interested merely in key problems so that I could do further reading. As I understand man-made energy storages are significantly less efficient than ...
3
votes
3answers
871 views

Requirement of energy for metabolic processes

Sorry if this is too elementary, but can someone explain why the following reaction can occur without a net influx of energy from some other process? $C_6H_{12}O_6 + 6O_2 \to 6 CO_2+6H_2O$ And why ...
3
votes
2answers
3k views

Where do mushrooms get their energy from?

I'm wondering where field mushrooms get their energy from. I've heard that they can easily grow on soil in a dark room. So, it seems to me that there wouldn't be any photosynthesizing plants from ...
3
votes
2answers
15k views

Why is a magnesium ion essential for ATP activity in enzymic reactions?

The Wikipedia entry on Magnesium in Biology includes the following: ATP (adenosine triphosphate), the main source of energy in cells, must be bound to a magnesium ion in order to be biologically ...
3
votes
1answer
283 views

Redox potentials in photosynthesis light dependent stage

In my lecture notes, it states ...there is a significant thermodynamic problem due to the respective redox potentials of the half reactions: H2O<--> 1/2 O2 + 2H+ +2e- pE=+0.82V ...
3
votes
1answer
1k views

Can a cell start a mitosis if it lacks energy or molecules to complete it?

I'm wondering whether a cell can start a mitosis if it lack molecules or energy to fully complete it. From what I'm reading on wikipedia the cell passes most of its time in the interphase in which the ...
3
votes
1answer
880 views

Relative roles of ATP and NADPH in anabolic and other processes

Chemistry isn’t my strong point, but I’m trying to understand why NADPH is said to be the main agent necessary for anabolic reactions, and if NADPH is used for anabolic reactions what is ATP used for? ...
3
votes
2answers
348 views

At what levels of muscle energy intake does catabolism start?

From my own reading, there are three ways used by the body to produce energy: Alactic anaerobic (direct degradation of ATP and creatine phosphate for regeneration of ATP) Lactic anaerobic (breakdown ...
3
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0answers
86 views

Recent research in bioluminescence powering photosynthesis?

In 2013 there was a Chinese study published on "Bioluminescence as a light source for photosynthesis," which is briefly summarized in this Chemistry World article. There was a question on Biology.SE ...
3
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0answers
135 views

Why is ATP the main nucleoside triphosphate used to exchange energy? [duplicate]

Out of all of the nucleoside triphosphates what makes ATP the most used? Is it its structure? The amount of energy it contains? Why is GTP not used as much? What is the deal with the other nucleoside ...
3
votes
0answers
66 views

What makes the amide bond the lowest energy pathway? [closed]

I've reading about proteomics and how it can be used with mass spectrometry to sequence digested peptides. Reading this paper the author states (in box 2): peptide fragmentation induced by ...
2
votes
2answers
584 views

Why a continuous supply of energy is needed to support a weight?

What motivates this question is the apparent discrepancy between the concept of Work in physics and in physiology. Work in physics is defined as the dot product of the force applied to move a certain ...
2
votes
1answer
171 views

Power consumption of a ATP synthase in Watts

Considering the ATP synthase to be a rotating machine, does anybody know its power consumption and/or power production in Watts? At least roughly, e.g. based on the average chemical energy produced ...
2
votes
1answer
85 views

Does the body prioritise the use of available sugar before fat?

Let's say you eat a very unhealthy snack that contains 90% sugar and 10% fat. Would somatic cells not start using the fat for energy until all the sugar is used up? Does the body not use fat at all ...
2
votes
1answer
55 views

How can low cholesterol cause mortality?

I am studying processes 1. stroke, 2. heart disease, and 3. cancer, and their mechanisms associated with low cholesterol which is a result of lowering cholesterol especially in elderly, Low ...
2
votes
1answer
691 views

What dangers would the wireless transmission of power through microwaves pose to living organisms?

If we were one day able to harness the power of "wireless electricity", and INTEGRATE it into society, what disadvantages and/or dangers to living organisms would become relevant at that point? To my ...
2
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0answers
17 views

How much energy can one muscle contraction deliver?

How much energy is available in a single muscle contraction? I'm guessing the correct units are J/kg, but I'm open to more correct units. I'm looking for work done, not total energy dissipated (not ...
2
votes
0answers
737 views

Why do Proteins store energy when the body already contains Carbohydrates and Lipids?

We already know that lipids are a source of long term energy and carbohydrates are much faster energy releasing sources. So why do we need specific proteins within the body to store energy? Are ...
2
votes
0answers
427 views

How much energy would it cost to synthesize all cholesterol requirements de novo?

Imagine a scenario in which some person is unable to absorb any dietary cholesterol because of some intestinal mutation (for example). Thus, they have no cholesterol available from their diet for ...
2
votes
0answers
116 views

How do human cells respond to mechanical pressure such as heel contact during walking?

Basically, I'd like to do a full accounting (inventory, assets, liabilities) of a human cell under mechanical pressure. For example, if in steady-state, does the cell consume more or less energy ...
2
votes
1answer
2k 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' ...
2
votes
0answers
1k views

Can a person's body produce enough electricity to break a wristwatch? [closed]

I know of someone who cannot seem to wear watches without the battery dying or something else about the watch going haywire. this person was told it is because their body is producing too much ...
1
vote
2answers
238 views

Why do plants create enough energy for the entire ecosystem? [closed]

In my environmental class, we were recently learning about the $10\%$ law that basically says only $10\%$ of the energy goes from one trophic level to the next. This got me thinking about why energy ...
1
vote
1answer
182 views

Does the energy from ATP hydrolysis vary among different cells?

I know that when ATP is hydrolyzed into ADP it gives 7.3 kcal/mol. The question is, does this value vary among different types of cells?
1
vote
1answer
68 views

What would happen if most the fat in your body was rapidly converted into energy in 2 minutes? [closed]

It all started out as an argument I had with my friend.He said that "it would be the equivalent of catching a fire and burning" But all I thought would happen is that you would now be very hyper ...
1
vote
1answer
486 views

Is some of the energy of food lost during digestion?

I know that chemical energy of food is converted to heat energy to be used by the body in many metabolic reactions. Specifically, I know that the breaking down of bonds is what releases energy. Does ...
1
vote
2answers
40 views

Is it possible to merge the genomes of photosynthesizing and electron-transporting bacteria to make an electric cell?

I had an idea of making electric current from bacteria. There are some bacteria that can photosynthesize, and some others are capable of transmitting electrons through each other. Is it possible that ...
1
vote
0answers
86 views

Energy consumption of the human brain: thinking vs not thinking [duplicate]

I'm wondering about the human brain's energy consumption at different "uses". If you use a muscle it uses more energy than if you hold it still. Is the brain like this, or is it "always on" like a ...
1
vote
0answers
75 views

Simplest known form of aerobic glycolysis

What is the simplest known way that an organism performs aerobic glycolysis? In other words, what is the simplest known way known to convert glucose into $\ce{H2O}$ and $\ce{CO2}$, other than by ...
1
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0answers
572 views

Fatty acid oxidation in adrenal medulla?

Why adrenal medulla can not utilise fatty acids for generation of energy? What could be the benefit for not having ability to use fatty acids? Refrence 1 Refrence 2
1
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0answers
99 views

How do red blood cells obtain energy without mitochondria? [duplicate]

RBCs don't have mitochondria so there is no Respiratory chain in them. But how does they get energy from Lactate. Because Lactate produce NADH which gives energy only in respiratory chain.
1
vote
2answers
204 views

Why do mitochondria waste energy?

In a mitochondria, it makes ATP by using energy from NADH and FADH2 electron to pump H+ into ...
1
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0answers
170 views

Does reproduction cause aging ? Is aging just a strategy to increase reproductive success in all organisms? [closed]

Background for why I am asking this: I read a book—modern biological theory and experiments on celibacy— which uses life history theory to imply that reproduction is the reason why organisms grow old....
1
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0answers
36 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 ...
1
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0answers
73 views

Protein modification and ATP consumption

According to wikipedia there exists a lot of ways to modify a protein (post-translationally). Just to mention few: phosphorylation, dephosphorylation, glycosylation... While phosphorylation requires ...