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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67 views

Are carbohydrates an essential component of human diet?

Are people able to satisfy all the needs of a healthy diet without consuming carbohydrates? My question includes the assumption that a person has no health condition that would prevent them from ...
2
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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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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 ...
2
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1answer
79 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?
2
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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 ...
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 ...
2
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1answer
55 views

Metabolism of different saccharides

Learning about carbohydrates, I wonder what the differences there are in terms of metabolism, and overall health between the different types of saccharides. In other words, does the body use ...
2
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1answer
87 views

Aerobe or facultative anaerobe organism that metabolizes acetate?

I'm assuming bacteria, but will take any suggestions. Organism must survive primarily on the acetate (plus trace elements), but I can give/take electrons, if necessary. Not interested in strict ...
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1answer
73 views

Why is duck fat less saturated than cow fat?

Why does the composition of fat in animals vary? Is there an evolutionary advantage to producing fat that is less or more saturated?
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1answer
166 views

How can we distinguish blended flavors?

As far as I know, humans can distinguish between 5 basic tastes based on various molecules in food and their interactions. There's a level to all 5 so there can be an endless variety of tastes, and we ...
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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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0answers
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 ...
2
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1answer
81 views

How do muscle cells synthesize glycogen?

Hexokinase enzyme is present in all cells (including muscle cells) and can be suppressed by excessive G-6-P product. So that's why in the liver, glucokinase can act on glucose without inhibition of it ...
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0answers
21 views

Which biosynthetic pathways take place in the plastid and were are they located?

I know that the isoprenoid, jasmonate, glucosinolate, fatty acids, chlorophyll, starch, and aromatic amino acid syntheses are located in the plastid. But I don't know if they are located in the ...
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0answers
76 views

Does the metabolic rate determine how fast the telomeres shorten?

In many papers one can read that telomeres may play an important role in longevity. According to Calado et al.1 the telomeres of mice are much longer than the telomeres of humans. However, mice have ...
2
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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 ...
2
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0answers
83 views

Why is a nicotinamide-tryptophan combination used to treat affective episodes in a few older clinical trials?

At least one of the journal articles that reported on such clinical trials allured to the nicotinamide-tryptophan pathway that I assume must be related to the metabolism of tryptophan into serotonin ...
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0answers
121 views

Are simple esters like those used as flavouring agents metabolised into their constituent carboxylic acids and alcohols in the human body?

By this I mean to ask whether say ethyl butanoate is hydrolysed in humans into ethanol and butyric (butanoic) acid. This is of interest to me as a pharmacology researcher because butyric acid, for ...
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0answers
43 views

How much does a human brain's metabolic rate vary? [duplicate]

Possible Duplicate: How does brain energy consumption depend on mental activity? Our brains consume about 20% of our energy when we're at rest. How variable is a human brain's energy ...
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1answer
221 views

Why does NAD+ become reduced if it gains a hydrogen proton?

I've heard that $NAD^+$ gains a Hydrogen proton during glycolysis and the Krebs cycle and becomes reduced to $NADH$. However, isn't reduction when a molecule receives an electron? Maybe I've been ...
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2answers
955 views

carbohydrates and lipids as a source of energy? why?

Why carbohydrates and lipids basically used as a sources of energy? Why only proteins are used as building blocks of all the creations? Yes there are some parts of cells like cell walls in which ...
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1answer
107 views

Is it easier to burn a calorie of fat or a calorie of a carbohydrate?

Say someone eats 100 calories of chocolate vs. 100 calories of carrots. Something tells me that eating the chocolate will lead to you generating more fat. Will it? Is it harder to burn the calories ...
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1answer
121 views

Where can I find the metabolic network for the human erythrocyte?

Where can I find the metabolic network of the human erythrocyte (red blood cell), in SBML format? The red blood cell metabolic network is a model that's usually employed in the literature [see refs ...
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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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1answer
326 views

Why does beta-2-Thienylalanine inhibit bacterial growth?

I'm trying to obtain a better understanding of the Guthrie Test, which checks whether people have a disease called PKU. The Guthrie test uses bacteria to check for Phenylalanine (the amino acid) in ...
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2answers
243 views

What are the differences between how glucagon and cortisol work to increase blood sugar?

As I understand, both cortisol and glucagon cause an increase in blood sugar concentrations. However I don't understand how they work differently or why they work separately. I would be very grateful ...
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1answer
44 views

Mitochondria variability per tissue in humans?

I would like to know the distribution of mitochondrial content per tissue type in humans. I understand the simple metric that energetically active or energy requiring tissues will have more ...
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3answers
134 views

What is the relationship between protein-protein interaction networks and metabolic networks? [closed]

I am trying to find out how these networks can be linked together. I know that Protein-protein interaction networks and metabolic networks both fall under the Intra-cellular type of biological ...
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1answer
48 views

What are good data on the Human Metabolic Model and where can I get them?

Trying to get a good SBML representation of the Human Metabolic Model for use in Flux Balance Analysis and drug targetting (i.e. gene knockout) simulations. What are good sources for these data? ...
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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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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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2answers
50 views

What are the differences between carnitine forms?

I've heard of L-carnitine, acetyl L-carnitine and L-carnitine L-tartrate. What form(s) occur in meat? What form does the human body manufacture? Is L-carnitine just a shortened name for L-carnitine ...
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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 ...
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1answer
91 views

Why use creatine phosphate?

We use creatine phosphate as an energy storage to resupply ADP with a phosphate group as our muscle cells only contain about 2-5 mM ATP. But why doesn't the muscle cells just keep 20-30 mM ATP instead ...
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1answer
91 views

Could the Warburg effect be used to starve cancer cells in situ?

What is wrong with the following chain of reasoning? Nearly all cancer cells rely on high rates of glucose uptake (upto 200 times more than normal cells). This is known as the the Warburg effect. ...
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1answer
190 views

How to relate human metabolic model reactions and cancer drug targets / reactome items?

Trying to find a way to take a cancer drug (from CancerDR, for instance) and infer the metabolic reactions that are affected by it in the Human Metabolic Model. Essentially, I would like to know ...
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1answer
49 views

What is the energy source for adipocytes?

Since adipocytes export fatty acids and glycerol and don't use them as an energy source, what is the main source of energy for adipocytes?
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3answers
259 views

Assay for Beta-galactosidase activity in single cell microscopy

I'd like to be able to measure the activity of $\beta$-galactosidase in living cells with simple optical (maybe fluorescence) microscopy. Ideally I'd like to do a minimum of genetic engineering, and ...
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1answer
44 views

Genotoxic agent and their metabolic pathway

What are the mechanics (set of biochemical reactions) allowing a given genotoxic agent to modify the mutation rate at a given spot? to induce only a given type of mutation (from Gs to Cs for ...
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1answer
71 views

Isoprenoid Diphosphate Concentration in Yeast saccharomyces cerevisiae

Isoprenoid Diphosphate(IPP) is an important metabolites which is precursor in lot of secondary metabolites like Dolichol diphosphate, ubiquinone, prenylated proteins and carotenoid (not synthesized ...
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1answer
817 views

Why does the hydrolysis of ATP increasing entropy increase the Phosphoryl-­‐transfer Potential?

I am currently taking a biology class. I do not understand this concept. I understand that the electrostatic repulsion of the negative charges, resonance stabilization and hydration stabilization all ...
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0answers
28 views

In glycolysis, what is the source of the electron that makes NAD+ into NADH instead of NADH+? [closed]

I looked at the formula for the glycolysis reaction. The overall reaction seems balanced, however, I don't see anything on the left hand side of the equation that would provides the electron to ...
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0answers
15 views

How are muscle fibre size and oxygen consumption related?

Does anyone know of a paper which correlates the muscle fibre size to oxygen consumption in mammals? I am trying to find a correlation between muscle fibre type, size and (absolute and specific) ...
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1answer
48 views

How does heat generated by metabolism differ compared with heat generated through exercise?

I am from a mathematical background so I don't have much knowledge on biology. I'm building a mathematical model to predict heat generation with parameters of metabolic heat generation and exercise ...
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0answers
30 views

What is the actual function of HDLs and CETP?

I know that HDLs collect cholesterol from peripheral tissues and transport it back to the liver using SRB1 - Reverse cholesterol transport and dumping it in bile. So the tissue is producing some extra ...
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0answers
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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0answers
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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0answers
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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0answers
20 views

How is the enzyme glycogen synthase regulated?

How is the enzyme glycogen synthase regulated in regards to glycogen synthesis? I think I understand that phosphorylation decreases its activity (through glycogen synthase kinase?), but what role do ...
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1answer
28 views

Does exercising increase the rate at which UV rays are absorbed and cause affects?

Does exercising while in sunlight affect the rate at which the human body absorbs and reacts to UV rays? As sunburn is the secretion of fluids, increased dilation of blood vessels and inflammation of ...