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Biology Stack Exchange

Questions tagged [energy]

for questions relating to chemical, mechanical, electromagnetic, thermal, kinetic or potential energy or any other energy related directly to biological organisms or biological systems

related tags: ,

Questions should not be about the chemical or physical properties of energy and should relate to biological organisms and biological systems.

81 questions
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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 energy from both oxygen and solar rays? If not, is…
LocalFluff
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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 the cell? Is there a benefit to using the ATP to…
tox123
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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 Adenine Dinucleotide (Phosphate) (NADH/NADPH),…
another 'Homo sapien'
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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 matter. Part of this organic matter is used for…
ylluminate
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6
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Why do we get tired

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 get tired?
I J
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What is the share of body energy that the brain consumes? Is 20% reliable?

"20% of the energy at only 2% of the weight" is a frequently regurgitated factoid. More precisely, it should read: 20% of oxygen consumption. The problem starts when one looks into the source experiment. The Wikipedia article on the brain offers…
SeanJ
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Pyruvate dehydrogenase: Apparently anomalous NAD/FAD redox reaction

Below is the mechanism for the reactions of the pyruvate dehydrogen complex, which oxidatively decarboxylates pyruvate and transfers the acetyl group to coenyzme A for further metabolism in the Krebs cycle. The key point is that after $\ce{FAD}$…
chematwork
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How come only a handful of animals can do photosynthesis?

As far as I understand, all the energy that living beings rely on comes from the sun. It's processed by plants in photosynthesis. These plants are consumed by herbivores, which in turn are consumed by carnivores. Energy trickles down that way, with…
Ram Rachum
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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 similar relationships from other sources but never…
quibble
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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, typically lighting up food with a red hot iron…
SeanJ
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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?
Anixx
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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 active or passive transport?
hello all
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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 commonly known as the anaerobic lactic pathway) and…
FenryrMKIII
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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". ATP is the energy currency of the cell, so, would…
DJG
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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 deficit hyperactivity disorder (ADHD) report "energy…
J.Todd
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