The set of biochemical reactions that sustain life by directly or indirectly affecting energy expenditure and/or storage, as well as the complete regulation of those reactions and the enzymes that catalyze them; including, hormonal, cell-signaling, and substrate level regulation.

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Can a computer display work as a daylight lamp?

During winter time I often see advertisements for daylight lamps which are supposed to compensate for the lack of daylight in a winter season. The specs of such a daylight lap seems to be an LED ...
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2answers
42 views

Is there a known or quantifiable correlation between capsaicin and its effect on the body's metabolism?

I've often heard that spicy foods can speed up your metabolism, I presume, due to the capsaicin. Though I'm sure this is a minor effect - I doubt eating a pound of jalapenos a day will help me lose ...
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2answers
421 views

Can a living organism run on electricity?

Each time I'm too lazy too cook I think it'd be cool to be able to just plug myselt into an outlet. Yet I know it is not possible - I need amino acids and a lot of other stuff that electricity can't ...
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18 views

metabolic heat generation and exercise intensity

Is there a relationship between bio heat equation (found here) and exercise intensity as described here That is I am trying to include the effect from exercises to the tempertaure variation in skin. I ...
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1answer
36 views

Are there differences in energy of glucose isomers?

There are many isomers of glucose, including galactose and fructose. Do they have different chemical energy levels, and why? What makes galactose and fructose useful compared to glucose, and would ...
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2answers
389 views

When glucose production is low, the brain begins using ketoacids as energy… how does that work?

Can someone very generally describe how the brain consumes ketoacids/ketone bodies when blood glucose has been completely depleted?
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1answer
163 views

ATP utilized in Glycolysis vs. Gluconeogenesis

In glycolysis, the conversion of glucose to pyruvate results in a net gain of 2 ATP molecules. In gluconeogenesis however, the conversion of pyruvate back to glucose requires 6 ATP molecules. Why ...
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1answer
601 views

Why does gluconeogenesis need to exist - it seems pointless?

The gluconeogenesis pathway seems quite pointless to me. I don't understand why an organism would want to spend energy to create a molecule that can then be metabolized again for less energy? The ...
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1answer
38 views

Why would growth hormone (somatotropin) cause both lipid AND glucose release?

GH increases lipolysis (lipid breakdown) and the release of fatty acids from adipocytes into the blood. Fatty acids then can be used as energy sources to drive chemical reactions, including ...
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29 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 ...
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1answer
8k views

What are the differences between white and brown adipose tissue?

What are the differences between white and brown adipose tissue? Here are some that I have come across: ...
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113 views

Why are Mammals are unable to produce Essential Fatty Acids?

Why do we have to get them from our diet, and if they aren't taken in our diet we will face disease? Then why we don't have the enzymes which are require for EFA synthesis?
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63 views

Giving life to a dead person [closed]

Could anyone please tell me whether we can conclude that no body of a dead human being can get life since all chemical reactions are irreversible in our human body?
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14 views

Metabolic control theory: proof of the summation theorem?

I'm looking for a rigorous proof of the summation theorem of metabolic control theory. The only sources I find are the original papers by Kacser and Burns 1973 and Heinrich and Rapoport 1974, both of ...
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1answer
17 views

Does the location of the double bond in chlorins yield a distinct biological function?

Chlorins differ by the number of double bonds and their location. Chlorin has 20 pi electrons, whereas bacteriochlorin and isobacterichlorin have 18 pi electrons, but at different locations. Do ...
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24 views

Which metazoans host anaerobes to aid in digestion? Do any host oxic digestive tracts?

Many metazoans (e.g., mammals, insects, earthworms) have anoxic digestive tracts that are colonized by anaerobic microbes that perform portions of digestion of food for the host. Some other metazoans ...
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1answer
33 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 ...
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3answers
178 views

Why is iodine used for metabolic hormones?

Iodine and related biological iodine-carrying hormones are phylogenetically very old, at least according to Wikipedia. Humans use iodine as a metabolic indicator, as do axolotls and apparently most ...
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1answer
52 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 ...
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1answer
59 views

what makes our body warm?

I would think that there would so many chemical reactions going inside our body,friction produced by blood in veins, subcutaneous and visceral fat acting as heat insulators. I was wondering to what ...
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35 views

Which Lactobacillales (Lactic acid bacteria — LAB) strains are capable of degrading starch?

I've been researching bacteria strains but am having trouble finding amylolytic LAB strains with amylolytic and lactic acid producing character. The only species I've found, that are capable of ...
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1answer
368 views

Why are many fruits sour?

Many fruits (like apples, berries, citrus fruits etc.) contain high levels of organic acids, especially malic acid and citric acid. Are there any evolutionary functions of those acids in ripe fruits? ...
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1answer
73 views

What are the metabolic concerns associated with hard water?

If humans can maintain a consistent blood pH, then what problems does alkalized water cause us? Why is it recommended that we filter and boil hard water? Is the issue that hard water can affect the ...
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1answer
625 views

How was the diversity between ethanol fermentation and lactic acid fermentation evolved?

Quite simply, some organisms metabolize glucose under anaerobic conditions via Glucose->(2) Pyruvic Acid->(2)Ethyl Alcohol. Some organisms, however, metabolize to lactic acid. When did such a process ...
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1answer
83 views

What happens when we eat excess fat?

The fats in our body are stored in fat cells. When we over eat fats does the size of our fat cells increase, are more fat cells generated, or do we "throw out" excess fat?
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1answer
893 views

Grapefruits and CYP3A4

Grapefruit juice contains furanocoumarins, which irreversibly inhibit CYP3A4. For this reason, when one is taking certain medications it is necessary to not eat grapefruits because the inhibition of ...
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2answers
169 views

Equilibrium and Metabolism: Can cells exist at STATIC equilibrium? What about dynamic equilibrium?

I understand that in closed systems, once reactions reach equilibrium, they can no longer be used to power other reactions. If a cell was a closed system (which it is not), being at equilibrium would ...
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311 views

Should we induce fever to assist healing?

I am currently reading "The Fundamentals of Anatomy Physiology" 10th edition, and have found it an incredibly interesting book. I have just been reading about the lymphatic system, and the various ...
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2answers
162 views

Energy released during the production of ATP?

When glucose is used during aerobic and anaerobic exercise, how much energy is expended or required? During aerobic exercise: $C_6H_{12}O_6 + 6 O_2 \to ATP + H_2O + 6 CO_2$ + energy During ...
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1answer
70 views

Catabolism and muscle energy intake

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 ...
6
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1answer
185 views

iodine: how did they manage without it in old ages? (People who were living far from the sea)

Knowing that today iodine comes either from fish products or (artificially) enriched table salt, how did people who lived far from the sea survive before (especially during the the Middle Ages)? Edit ...
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3answers
2k views

Is lemon water an alkalizing agent in the body?

I was recently having a discussion with someone about whether lemon water actually increases the pH of your body (by which I assume they mean the blood); their claim was that once Citric acid was ...
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11 views

What's the relationship between Drugbank drugs and SMPDB pathways?

In the 'pathway browse' panel SMPDB pathways and their corresponding Drugbank drugs are listed. What are the relationships between the drugs and the pathways? Some listed drugs are not in the ...
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1answer
37 views

What does “each pathway define an independent genotype” mean?

In a section of this paper. However, if the question of independency is posed in the form: “Does each pathway shown define an independent genotype?,” then each of these three pathways is ...
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1answer
56 views

What is the meaning and significance of extreme pathways

Can someone please explain me what extreme pathways are? I found this definition in this article: Extreme pathways are a unique and minimal set of vectors that completely characterize the ...
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151 views

Where do the H+ ions come from in light reactions?

In the light-dependent reactions of photosynthesis, H+ ions pass to the thylakoid space. Where do these protons come from?
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2answers
6k 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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2answers
133 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 ...
2
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1answer
35 views

MTHFR recessive alleles and B-vitamins

I know that being heterozygous or homozygous recessive for the MTHFR gene prevents that person from being able to process and use folate and B-12. It causes an unhealthy level of homocysteine to ...
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3answers
24k views

Why can't the brain and red blood cells use fuels other than glucose?

The question is rather straight forward: I have always been curious as to why, but cannot find an explanation online. I can imagine that the mechanism is different for each, but why does brain tissue ...
3
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1answer
109 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 ...
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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?
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2answers
253 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 ...
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1answer
166 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 ...
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0answers
48 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 ...
3
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2answers
127 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 ...
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1answer
28 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.
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30 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?
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1answer
74 views

Do muscles still hold glycogen reserves if there is no carbohydrate input

Afaik skeletal muscles take glucose from the blood to store it localy as glycogen, to be used in the case of intensive exercise. Does this still happen if the calorie input is exclusively made up ...
9
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1answer
717 views

Why is the brain dependent on glucose?

The strict dependence of the (human) brain on glucose has always been puzzling to me. While ketones can substitute for a portion of the brain's energy needs, it cannot substitute completely: blood ...