Questions tagged [energy]

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How many calories does a person consume when sitting at a computer per hour, depending on body weight?

Suppose a person weighing 75 kilograms does three activities: Sleeps Sits working at the computer Going home from work. I need to know how many calories his body will consume in each of these cases ...
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30 views

How does shortage of oxygen halt the NADH dehydrogenase complex?

I understand that in the absence of oxygen the functioning of cytochrome c oxidase stops because it is its substrate. However I don’t understand how stopping cytochrome c oxidase also stops the ...
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Does our brain use up more ATP after smoking cannabis?

kind of an amateur here. If the firing of the neurons' signals uses up some ATP, and smoking cannabis makes them fire off more quickly, do our brains use up more ATP to sustain that rapid firing?
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32 views

Fuel from photosynthesis

I was reading how plants make use of sunlight, CO2 and some other stuff to make energy. So why can't we create artificially engineered bio solar panels which will take sunlight, C02, water and other ...
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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 ...
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3answers
1k views

What is the energy produced by the mitochondria? [closed]

I know that the mitochondria is basically the power house of the body, it consumes amino acids, fatty acids, glucose, etc and oxygen. When these molecules meet up in a enzyme, a series of reactions ...
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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 ...
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111 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 ...
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1answer
888 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 ...
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1answer
188 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 ...
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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 ...
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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 ...
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1answer
47 views

How does the human body power itself? [closed]

This query can be divided into sub-queries: What form/s of energy does the human body "run" on? Why/for what are these particular forms of energy required? From what can these types of energy be ...
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91 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 ...
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76 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 ...
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1answer
83 views

Is there evidence to suggest that sleeping requires more energy than watching TV?

I have heard the claim: sleeping requires more energy than watching TV. I have heard the counter-claim - watching TV requires large amounts of energy. My question is: Is there evidence to ...
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1answer
185 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?
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714 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 ...
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361 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 ...
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1answer
4k 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?
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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 ...
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2answers
106 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". ...
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1answer
518 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 ...
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633 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
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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 ...
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2answers
345 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 ...
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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.
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1answer
81 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 ...
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306 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 ...
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112 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.
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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 ...
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1answer
541 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 ...
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2answers
254 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 ...
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2answers
102 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,...
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1answer
976 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? ...
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949 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 ...
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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 ...
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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 ...
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48 views

How does plant life obey the constraint that the change in Gibbs free energy in a reaction must be negative?

My understanding is that if a reaction takes place, either entropy of the system must rise, or energy must be released from the system as heat, or both. (Citation: paraphrasing from The Vital Question,...
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2answers
809 views

Energy coupling between two spontaneous reactions?

This diagram describes energy coupling between a nonspontaneous reaction (the formation of glutamine from glutamic acid and ammonia) and a spontaneous reaction (the hydrolysis of ATP). I can see that ...
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173 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....
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1answer
87 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 ...
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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 ...
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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?
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1k views

What is ATP and why is it said to be a source of energy? [closed]

Is ATP a molecule or a kind of energy. When I studied the active transport, it's said the ATP would release energy to change the carrier protein shape. So confused. Thanks for your help.
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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 ...
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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' ...
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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 ...
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93 views

Why are carbohydrates the most common short-to-medium-term energy storage form in biology?

According to this table, gasoline has a specific energy noticeably higher than fat and more than twice that of carbohydrates; even short-chain hydrocarbons like ethanol and even methanol offer an ...
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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 ...