7 votes
Accepted

Organic battery?

I don't have the math at hand for the actually energy efficiency, but let's just start from the storage capacity. Basically, an electric eel wouldn't make a very good battery. They could be a decent, ...
Bryan Krause's user avatar
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7 votes
Accepted

Are there known life forms that are able to transform mechanical energy into chemical energy?

There are no known life forms that use mechanical energy as a primary form of metabolic energy (i.e., for generic cellular functions). Many life forms are sensitive to mechanical disruption in some ...
Bryan Krause's user avatar
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7 votes

Are there known life forms that are able to transform mechanical energy into chemical energy?

This is definitely not my field, and I have no interest in science fiction, but the question struck me as interesting, and brought me to an area of bimolecular science that may be relevant to the ...
David's user avatar
  • 25.2k
7 votes

What determines whether a reaction using ATP produces ADP or AMP?

Summary It is the nature of the biochemical reaction that determines whether a reaction of ATP involves hydrolysis of the β- or γ- phosphoanhydride bond. If a part of the ATP molecule is incorporated ...
David's user avatar
  • 25.2k
6 votes

How do plants store energy by potassium battery?

I'll give it a layman's attempt in sort of an "ELI5" approach. I hope the analogy isn't too simplistic, and please don't take it too literally. How do plants use K+? Plants control K+ concentrations ...
Bryan Krause's user avatar
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5 votes

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

This is an interesting question (I really mean this — see below), for which a straight answer is remarkably difficult to find on the web. When I googled for it I got pages with statements that ...
David's user avatar
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5 votes
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Is Chemiosmosis a hypothesis or a theory?

Preamble Although there is a case for closing this question (it is two questions, the first of which is more linguistics, logic or philosophy of science, and the second well-covered in text books) I ...
David's user avatar
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4 votes
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Is co-transport within a cell active or passive transport?

Co-transport, also called secondary active transport, is a form of active transport because it is using the energy from one concentration gradient to transport another molecule across the membrane ...
canadianer's user avatar
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4 votes
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Does the energy from ATP hydrolysis vary among different cells?

Yes, the energy from ATP hydrolysis can vary between different cell types and condition, because it depends on several factors. Hence, you will find different values in various textbooks. First, like ...
Roland's user avatar
  • 5,705
4 votes
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What are the limiting factors of human stamina?

A few explanations at the cellular and molecular level: First, for contraction to happen, muscles need signals from nerves. Replenishing the pool of neurotransmitters (used for each synaptic burst) ...
Mowgli's user avatar
  • 1,933
4 votes

How many Watt-hours can an electric eel produce in a day?

This research states that an eel whose size is 90 cm can provide 6.05 mW, which is 145 mWh every day. They say you'd need 165 eels to be able to read for 24 hours using a 1W lightbulb like the one on ...
bandybabboon's user avatar
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4 votes

What is the latest estimated probability for the self assembly of a primitive cell?

I think that it's worth directly examining the citations of the book in question. In doing so, I found the following quote: The abundance of the first 31 elements in the Periodic Table on Earth and ...
Maximilian Press's user avatar
4 votes
Accepted

Which cells in our body perform lactic acid fermentation?

Certain human tissues can be considered completely aerobic (e.g. liver) or anaerobic (e.g. erythrocytes) in their energy (ATP) production. However it is wrong to think, as some other recent questions ...
David's user avatar
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3 votes

Could a mammal convert ingested dissolved CO2 to usable energy?

There isn't any biologically useful energy in CO2. In fact, humans and all other animals produce CO2 as a waste product at the end of metabolism specifically because it is low-energy. You don't need ...
Bryan Krause's user avatar
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3 votes

Could a mammal convert ingested dissolved CO2 to usable energy?

No. What is lacking from the question is a logical framework for the possibility suggested — that carbon dioxide can be a source of energy — and I suspect that this is because it lacks a clear ...
David's user avatar
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3 votes
Accepted

Location of t tubule in muscle

Interesting question. Indeed it is related to the working of cardiac muscles. First of all, lets have a look at the structure of a sarcomere of a cardiac muscle from here: Here, what we can see is ...
another 'Homo sapien''s user avatar
3 votes
Accepted

What are the known energy capturing processes in biological systems?

Apart from phototrophy, there is only chemotrophy (obtaining energy from redox reactions of chemical substances) and radiotrophy (obtaining energy from ionizing radiation such as gamma rays). However, ...
WYSIWYG's user avatar
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3 votes
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How efficient is the human body at metabolizing food?

A year and a half later, I stumbled upon this article by Ars Technica. To summarize, research/experts acknowledge that the calorie system is a poor way to measure human metabolic performance. Gut ...
WannabeCoder's user avatar
3 votes
Accepted

Cellular respiration in carnivorous animals

Your guess is correct: glucose is not the sole source of energy in the cell! While cellular respiration is the classic mechanism for energy production (in the form of ATP) in the cell, there's ...
Dubukay's user avatar
  • 808
3 votes

How does the light-independent stage of photosynthesis get H+ ions?

Summary The question shows confusion about the purpose of the splitting of water in photosynthesis. Quoting from Berg et al., in the light reactions of photosynthesis “Light is absorbed and the ...
David's user avatar
  • 25.2k
3 votes
Accepted

Why is hydrogen to oxygen ratio used to compare energy storage efficiency?

Answer In my opinion: The original poster’s overall interpretation of the statement in the article (as reported) is most likely correct. Problems with original statement Although the statement may ...
David's user avatar
  • 25.2k
2 votes

How did scientists establish the reactions that occur in metabolism?

In addition to biochemical methods, a lot of this was figured out using radioactive tracers. Cells would be fed a radioactive substrate and as they convert the substrate to other molecules through ...
Victor Chubukov's user avatar
2 votes
Accepted

Can the Na+/K+ pump backwards to generate ATP?

All enzymes can theoretically catalyze the reverse reaction. Researchers have driven the Na+/K+ ATPase to synthesize ATP with artificial ion concentrations: We have studied the apparent affinity ...
canadianer's user avatar
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2 votes
Accepted

How are electrons entering the electron transport chain in cellular respiration energised (excited)?

It may be useful to start with a quotation from the Introduction to Ch. 9 of Berg et al. Biochemistry (6e) that addresses the question, more or less as asked. I can’t find a link to the pages in the ...
David's user avatar
  • 25.2k
2 votes

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

Yes there are, though I had to dig a lot to find them. They are called strictly fermentative bacteria. Lactic acid bacteria (Lactobacillales (Firmicutes)) ferment glucose through pyruvate to lactate ...
István Zachar's user avatar
2 votes
Accepted

Activated carrier molecules and their relationship to enzymes

I will focus on the meaning of ‘activated carrier molecule’ as descriptions of enzymes abound. In order to do that I need to introduce two other ideas first. I apologize to the purists for tailoring ...
David's user avatar
  • 25.2k
2 votes
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How do cellular conditions change the Gibbs free energy of a reaction?

To understand that, you must have a basic understanding of Gibbs-Helmholtz equation. it states- $\Delta G'=\Delta G^{'o} +RT\,ln\,(Q) $ Here, $\Delta G'$ = biochemical free energy change & $\Delta ...
ANA negative's user avatar
2 votes

What are the roles of ATP and ADP in muscle contraction?

As a first approximation, I think your explanation makes sense. You can imagine the system having a spring, and the hydrolysis of ATP providing the energy to load the spring (store the energy in the ...
Domen's user avatar
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2 votes

Do ATP generated aerobically and anaerobically have different phosphorylation potentials?

Based on the way this question is phrased, the answer is trivially no. No matter how you make an ATP molecule, if you measure hydrolysis in a consistent manner there will be no difference. A ...
stords's user avatar
  • 957
1 vote

What are the (evolutionary) advantages of secondary transport?

I think an easy analogy for why this approach evolves is to think of how humans use electricity (or energy more broadly). Although it is feasible to have localized electricity generators (for example,...
Bryan Krause's user avatar
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