The set of chemical reactions that happen in the cells of living organisms to sustain life.

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Bacterial/microbial metabolism of sucrose in fruit juices

While taking out the recycling this morning, I noticed that my old orange juice carton seemed to be inflated. Opening the cap relieved a lot of pressure built up inside the carton. I'm thinking that ...
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Plotting metabolic networks?

I need to draw a map of the core metabolism of E.coli. Associated with each reaction in the map I have a number that indicates the flux through this reaction. I want the map to reflect these fluxes ...
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How much mmol/L of glucose does my dog extract from his meal into his blood?(at least roughly) [on hold]

In the context of insulin dependent diabetes(assume there is no glucose suppression in the blood at all, not even from the kidneys). I can find out the content of carbohydrate, but, I don't know what ...
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24 views

How does the cell regulate different metabolic pathways?

I heard somewhere that cells use different nucleosides bound to triphosphates e.g. ATP, GTP, CTP and other modified compounds: NADH, NADPH to distinguish between different metabolic pathways and so ...
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Is there any use of CO₂ in human body?

We all know CO₂ as a waste product of metabolism . Does CO₂ have any helpful role , apart from having a role in pH of blood ?
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Need for two oxygen sensors in E. coli

E. coli has two oxygen sensors: FNR (fumarate-nitrate reductase) and ArcBA (Anoxic Redox Control, two component control systems). FNR directly senses the oxygen, while the interaction of ArcB with ...
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46 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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85 views

In which way would the yeast cell cope with the excess amount of methionine in the growth media?

I guess that when there is surplus of methionine in the cell it is incorporated in the TCA cycle as a succinyl CoA, with cysteine as a by-product. But now the cell has the surplus of cysteine. What ...
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What is a coupled reaction and why do cells couple reactions?

I was wondering what exactly a coupled reaction is and why cells couple them. I read the wikipedia article as well as several others, such as life.illinois.edu but I still don't get it. Could ...
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570 views

Why is the Krebs cycle considered a part of aerobic metabolism if molecular oxygen is not involved in any of the reactions in the cycle

Why is the Krebs cycle considered a part of aerobic metabolism if molecular oxygen is not involved in any of the reactions in the cycle? I originally thought that Krebs cycle was aerobic metabolism ...
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How reactive are reduced antioxidant molecules?

When antioxidant molecules stabilize free radicals, they themselves become unstable and reactive but to a lesser degree. How reactive are these reduced antioxidant molecules? And what substance ...
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48 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 ...
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69 views

How did people who were living far from the sea obtain iodine during the Middle Ages?

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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34 views

Can chitosan affect the absorption of unsaturated fatty acid?

I know chitosan will decrease the absorption of fat. However unsaturated fatty acid, such as DHA, is beneficial. Does chitosan effect the absorption of unsaturated fatty acid?
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132 views

What is the mechanism of oxygen uptake in E. coli?

How does E. coli uptake oxygen? Most of the literature I found is concerned with response to oxygen level supplied in the medium, as opposed to how much is actually transported inside. Can they shut ...
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2answers
365 views

In humans what is the last metabolic process to cease after death?

After death which of our body's metabolic processes will continue functioning for the longest?
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Poly Unsaturated Fatty Acid

PUFAs spontaneously oxidize, speed up the process of glycation, since too much glucose and they also decrease mitochondrial respiration - more oxygen and CO₂, less lactate and PUFA also promote ...
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136 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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How do antioxidants affect human metabolism?

I'd like to know how antioxidants affect human metabolism and which ones are essential for metabolic processes.
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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 ...
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25 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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291 views

What is an irreversible reaction?

There are reactions with large Delta G negative values. Why these reactions are irreversible? As in: out of 10 steps of Glycolysis, 3 are irreversible steps. I need an explanation for why they are ...
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1answer
70 views

How efficient is the human body at metabolizing food?

My friend and I were having a discussion over how "efficient" human digestion is. If a human ate a 1000 calorie hamburger, how many of those calories (how much energy) does the body process into ...
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52 views

Oxidation means inflamation?

All right, I was reading article on nutrition, that focussed on content analysis of pastry-like food product for kids. I have to say that I am not sure this article would pass the imaginary smell ...
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25 views

Is there sugar secreted into blood even after complete digestions in healthy humans? What about dogs?

Suppose we're feeding a high GI food to a person and that the digestion lasts five hours. Does the body secrete sugar into the blood afterwards? What about in diabetic dogs and humans? Update: I am ...
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Why are carnivorans more efficient predators than birds or reptiles?

The Wikipedia page on island gigantism says, "Birds and reptiles generally make less efficient large predators than advanced carnivorans. What does it mean for a predator to be "efficient" and why are ...
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4answers
812 views

Why do we weigh less in the morning?

At first I thought it may be related to physics. You know, in one half of the day, the gravity changes, and the scale shows a different weight than the other. Then at night, gravity intensifies, and ...
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Why is my faeces black in color after eating Oreos

Why is my faeces black in colour the morning after I eat some Oreos? Day 1 : Eat a handful of Oreos & the next morning your stool is black. Day 3 : Eat a handful of cocoa flavored biscuits & ...
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104 views

The smell from eating asparagus

I am wondering about one thing. I have read different accounts of this (prior to reading it on Wikipedia), so I am wondering. Here are the two versions I have read: asparagus leads in a certain ...
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73 views

Consumption of NAD+ in glycolysis

Out of 10 steps in glycolysis, only one reaction- Glyceraldehyde 3-phosphate (G3P) to 1,3-bisphosphoglycerate (PGP), uses NAD+ and thereby producing NADH. Furthermore, this very step is solely ...
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In Japan, the official average body temperature is 36.0 °C. Why so different from that of Europe?

The Japanese Wikipedia states that the average human body temperature is 36.0 °C (here,"ヒト"). The statement references the data from the Japanese government. Actually all of my Japanese friends think ...
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814 views

Why our body does not produce polyunsaturated fatty acids?

Our body does not produce two polyunsaturated fatty acids (PUFA): linoleic acid and alfa-linolenic acid. I am thinking reasons for it. Saturated fatty acids have more energy than unsaturated. ...
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45 views

naturally occuring fatty acids

The double bonds in naturally occurring fatty acids present in our body are in cis configuration while the enzymes for beta oxidation can act on trans double bond. Then what will be the significance ...
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71 views

What organism most efficiently converts a given quantity of mass into heat?

Question I am trying to answer: In the popular film The Matrix, heat given off by humans is harvested as an energy source. I wondered, if this were possible, would humans be a good organism to ...
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130 views

Why doesn't Diabetes cause death by starvation?

The main cause for diabetes is lack of insulin in the body. Insulin is the hormone that allows body cells to absorb glucose from the blood. With out insulin, the body cells can't get glucose from the ...
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amino acid containing branched side chain

Branched-chain amino acid are degraded by branched chain alpha-keto acid dehydrogenase complex. These amino acids aren't degraded in liver because of the absence of this enzyme(in liver).Why the ...
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31 views

bacterial cell wall degradation in humans

can human degrade the D-amino acid present in bacterial cell wall, I'm confused about it i have read somewhere that human can do so.If yes than why we need antibiotic to kill bacteria???If it is not ...
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Where can I find a list of common enzyme cofactors and/or co-enzymes?

Where can I find a list of enzyme cofactors and/or co-enzymes, ordered by how common they are? For example, $O_2$, $H_2O$, $ATP$, $ADP$, $NAD$, should be ranked in the first places, because they ...
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151 views

what is the margarine metabolism in our body?

margarine is commonly used food ingredients that contribute to both inflammation and obesity , but actually I want to know the margarine metabolism in the human body I can find some resources talk ...
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Experimental studies of bacterial adaptation to changes in nutrients of culture medium

Are there experimental studies that measure how a population of bacteria in continuous culture evolve when submitted to changes in the concentrations of metabolites in the culture media? For example, ...
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desaturation in fatty acids [duplicate]

humans are unable to synthesize EFA what is the reason behind it that humans cannot introduce double bond between C-10 and the methyl terminal?
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124 views

How should I feed and keep an ant queen?

I have captured wandering ant queen. I guess she was just fertilised and was looking for a place to start a hive. I'd like to create my own ant hive in artificial environment. I unfortunately only ...
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Why Mammals are unable to produce Essential Fatty Acids?

While 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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33 views

Currency metabolites vs. current metabolites: What's the right term?

I have seen the two terms currency metabolite and current metabolite used interchangeably. Is there a consensus on which is the ...
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1answer
84 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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103 views

What are the lifetimes of cellular components on organelle or molecular level?

I was thinking that even though I know how generally the cell works, I don't really have a feeling of how volatile it is. I want to know what is the lifetime/turnover rate of different constituents of ...
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62 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
117 views

Anaerobic respiration choice in E. coli

Under anaerobic conditions E. coli has two options to generate ATP: fermentation (substrate-level phosphorylation), and respiration (proton gradient, chemisomotic phosphorylation). Which is favored? ...
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1answer
154 views

What marine animals exhibit deep hibernation/aestivation?

Do marine animals exhibit deep hibernation/aestivation as land-based creatures do? If not, Why?
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What Are the Exit Routes of Vaccine Adjuvants?

The digestive and respiratory systems are set up to process externally introduced "stuff." Most vaccines are given via an intramuscular route. What happens to the virus and the adjuvant materials ...