Questions tagged [metabolism]

Metabolism is the set of defined biochemical transformations occurring within the cells of living organisms.

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How well does “basal rate of amino acid catabolism” correlate with dietary requirements for amino acids?

To what extent does the basal rate of amino acid catabolism account for the dietary requirements for amino acids (and, the resulting need to evolve organs to dispose of excess nitrogen)? The ...
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Budget for essential amino acid intake, what degrades endogenous amino acid pool?

Any organism unable to synthesize all amino acids has to eat their essential amino acids. They only have to do so because their existing pool of those amino acids, within their body, is diminished. ...
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Does cellular respiration use amino acids even if it has other substrates like glucose?

Thinking about the "nitrogen budget" in animals (ranging from protists to Porifera, Radiata, invertebrates and vertebrates), I had the idea that cellular respiration might not be able to selectively ...
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Non-reusable use of amino acids, and amino acid consumption, budget perspective

Protein catabolism tends to break down proteins into its constituent amino acids. These can then be re-used to produce new proteins. Those processes are reusable, reversible. Consumption of proteins ...
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Occurrence of non-functional, “spontaneous”, amino acid degradation?

Animals tend to have to consume proteins continuously. Amino acids are often degraded by synthesis of other compounds, including glucose and cellular respiration, catecholamines, etc, accounting for ...
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Any phyla in Animalia that does ammonia assimilation?

A key step in nitrogen metabolism is the initial assimilation of inorganic ammonia into amino acids. Are there phyla within Animalia that do assimilation of ammonium (NH4+)? Phyla with symbionts from ...
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Can erythrocytes Function without plasma?

my title is not very specific. So i will proceed to clarify it. I am trying to make sure that the only blood cells in a sample are Erytocytes, since i want to evaluate their metabolism, I am aware ...
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Caloric needs during metamorphosis in insects, frogs, etc

Do caloric needs increase during metamorphosis from caterpillar to butterfly or juvenile tadpole to adult frog?
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Can the human body store protein?

I am interested to know if a human body can store protein. Absolutely for the bodybuilders, does it really matter if they divide their protein consumption during the day or eat all of it in one meal ...
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Can heterotrophs use anabolism to obtain energy?

With that question I mean: directly. Please bear with me, as I don't know much about Biology or Chemistry (those are my main difficulties while studying). I know that energy that biological beings ...
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Why do patients with type 2 diabetes not show the body wasting seen in type 1 diabetics?

Type 1 diabetes results from the destruction of the cells in the pancreas that produce insulin, while type 2 diabetes is characterized by so-called "insulin resistance", presumably a reduced ...
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How does temperature affect metabolism of warm blooded animals (homeotherms)?

In cold blooded animals (Poikilotherms) the temperature has a profound effect on metabolism. When the external temperature is raised a corresponding rise in internal temperature followed by a rise in ...
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Looking for Older KEGG global map

I'm looking for the global KEGG map from around 2017, so I can follow the corresponding map in this paper (Figure 4) easier. While the current global KEGG map mostly maps, I'm trying to easier figure ...
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Regulation of the TCA cycle and glycolysis by adenine nucleotides

Why is the tricarboxylic acid cycle regulated by the ADP/ATP ratio as stated in the following quote : Isocitrate dehydrogenase is allosterically stimulated by ADP, which enhances the enzyme's ...
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How much does 10g of glucose raise the blood glucose level?

If you would calculate it: ~5 liters of blood = 50 deciliters 10g glucose = 10000 milligram so the glucose level raises by 10000mg/50dl = 200mg/dl However, it is known that ingesting 10g glucose ...
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What happens to glucose taken up by the liver in type 1 diabetes?

Type 1 diabetes is caused by insufficient insulin production. Unlike in muscle and adipose tissue (GLUT4), glucose uptake by the liver is by GLUT2 and thus insulin-independent. Consequently, under ...
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Why does the liver produce ketone bodies instead of exporting acetyl-CoA from beta-oxidation for use elsewhere?

Under conditions of low oxaloacetate in the liver, acetyl-CoA that cannot be oxidised in the TCA cycle is converted to ketone bodies, which can then be exported for use as fuel in non-gluconeogenetic ...
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How does coffee cause calcium loss in our body?

Recently on radio a doctor advices to reduce the consumption of coffee as it leads to calcium loss(as my mother described). My initial response was: How could such thing be possible? What kind of ...
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How to calculate grams of fat used during hibernation?

In Humphries et al. 2002. Nature, the authors report number of grams of fat bats use during hibernation. However, their equations results in values in mlO2/g. How can one convert the energy ...
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quantification of glucose utilization in different metabolic processes

Glucose is commonly associated with ATP production. However, only a small fraction of glucose is utilized this way. The intermediates of glycolysis, TCA cycle, etc. are precursors to various ...
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What is the relationship between cell size and metabolism?

What effect does a bigger cell have on its metabolic activity? I understand that bigger cells need more energy, but surely smaller cells may have high metabolic rates too due to their efficiency?
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What happens if an enzyme stops working in the body?

For example, if the enzymes in the digestive system stop working will the digestion still occur as enzymes are only catalysts for the reactions. Thank You
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A biological system to measure time

First of all I am a physicist, so I apologise for my non-existent understanding of basic biology. However, I have what I think is an interesting question and this seems like a good place to ask it... ...
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During weight loss, do we inhale more oxygen?

During weight loss, triglycerides which are composed of carbon, hydrogen and oxygen, are broken down. During respiration, the inhaled $O_2$ is bonded to a carbon atom to form $CO_2$ which we exhale. ...
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Does the arrangement of amino acids in a protein matter for nutrition?

Let's say there are two diets, consisting of entirely different proteins. If you split up all of the proteins from one day of each diet, you'll get the same set of amino acids and the same count of ...
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About the definition of ketogenic amino acid

I am studying biochemistry and have been looking at metabolic network diagrams showing the different intermediates of glycolysis and the citric acid cycle that amino acids can be converted to. I have ...
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May two reactions, that share the same reactant, fire at the same moment?

I'm studying metabolic networks from a bioinformatics point of view, but I guess my question is pretty biological so I thought that maybe here I could get the best answers. So, as the title says I ...
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Can you predict what the metabolites of pipradrol would be? Are they similar to those of methylphenidate? [closed]

As these drugs are structurally very similar, I am curious about how the body would handle them. Ritalinic acid is a major metabolite of methylphenidate, but that's about all I know. Thanks ...
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Does food lose some of its mass in form of energy during metabolism?

I had an argument with someone. I argued that when a cat eats 1 kg of food, the sum of subsequent output (poo + pee + sweat + change of body mass) must be equal to 1 kg. My opponent argued that the ...
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What is a flux control coefficient?

In metabolic control analysis, a number of coefficients are defined, including the flux control coefficients. How is this coefficient defined and what does it measure?
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What enzyme or bacteria could dissolve plastic?

What enzyme or bacteria could dissolve plastic aside from acetone? Preferably, low-cost and environmentally friendly. Any suggestions would be helpful. I'm targeting for thin plastic (low-density ...
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Why does entering cryptobiosis make an animal more resilient to extreme conditions?

I recently learned about tardigrades which can withstand extreme conditions by entering a cryptobiotic state. Based on googling and wikipedia, supposedly in this state, their metabolism supposedly ...
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How important is getting enough glucose for maximal brain performance / cognition?

I know from many studies that have been done, that resting versus active use of the brain has relatively similar overall energy expenditure levels. On the other hand, however, we know that the brain ...
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Is cellular biomass synthesis and reactive oxygen species generation coupled with each other in cells?

Assuming that total ROS = ROS generated during biomass synthesis + ROS generated for other metabolic tasks, is it possible to quantify the amount of ROS generated specifically during biomass synthesis?...
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Can radiation exposure cause cancer later in life even if no traces of radioactive material are present in the body anymore?

I had a long-lasting debate with a friend of mine about the Fukushima incident. The question that we tried to solve was if radiation or toxin exposure can cause cancer later in life even if no ...
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What triggers the switch between aerobic and anaerobic respiration?

I understand that when there is a shortage of oxygen cells convert the pyruvic acid from glycolysis to lactic acid to regenerate NAD+. What I don’t understand is how they switch to anaerobic ...
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Could certain drugs enable one to consistently eat above TDEE or BMR without fat gains?

I heard anabolic steroids and stuff like DNP and ephedrine and etc. can somewhat enable one to eat more and get away with it without much or any fat gain, despite eating more than the body would ...
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Is it possible to stop more/extra fat from being stored in the body?

I don't mean simply by restricting eating or upping the activities, but a way to basically stop the body from adding more fat on itself down on the bio level. For example, I'm not too knowledgeable on ...
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What is the difference between Warburg effect and Crabtree effect in metabolism? [closed]

In addition to answering my question, please suggest a good review article that provides comparison of the above effects. Which pathways affect central carbon metabolism to produce these effects? Also,...
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What is the net effect of pancreatic somatostatin and how is it regulated?

I've read the following facts about pancreatic somatostatin released from delta cells of the islets of Langerhans: Blood glucose, fatty acids, and plasma amino acids stimulate somatostatin ...
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Why is urea not converted to ammonia in the body?

After the liver processes metabolites to produce urea and other by-products, these travel in the blood to the heart, then they are oxygenated, and some travel through the renal artery to the kidneys. ...
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Is there a relationship between HDL-C and LDL-C?

For a gentle introduction to cholesterol and its functions, see a great answer on SE Biology Whenever I read about how to deal with cholesterol level, the rule is to keep a low LDL fraction, ad a ...
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Is homocysteine converted to glutathione during oxidative stress?

From the paper titled "The basis for folinic acid treatment in neuro-psychiatric disorders" by Ramaekers et al., 2016: On the left side of the figure, the purine metabolite GTP serves as the ...
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How much energy does a spider expend per day just waiting for its web to vibrate?

Roughly speaking, a small, complex electronic circuit or IC might sit in "sleep mode" using a current of roughly 1 µA (e.g. 1, 2), thereby using roughly $3\times 10^{-6}$ Watts, and that ...
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How is Saccharomyces cerevisiae grown on acetate and ammonium able to produce TCA intermediates?

I am working with a metabolic model of Saccharomyces cerevisiae and I am studying its growth on acetate and ammonia. I am performing Flux Balance Analysis to compute the growth rate and then I am ...
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Is the lac operon repressed in the presence of both glucose and lactose?

In the presence of both sugars (glucose and lactose) will there be repression of the lac operon completely? I know that more glucose means less cAMP --> less CAP --> less positive regulation, and ...
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What does differential consumption mean? [closed]

I have not been able to find any definition of differential consumption online. What does it mean in this quotation? Vertebrates can influence natural fire regimes in several ways. First, ...
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What's the relationship between oxygen consumption and ambient oxygen concentration for a lobster?

I was looking at a research paper by Thomas (1954) and came across a graph with ambient oxygen concentration plotted against oxygen consumption rate of a European lobster kept in water. As we can see,...
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What is the genetic background for fast metabolism?

I am wondering if it is possible that people with very fast metabolism have some genetic mutation. There are people who can eat a lot while others would definitely get fat with such a diet. In other ...
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What's the lowest temperature a tardigrade can remain active at?

There's a lot of information floating around the net about how tough they are & what they can survive, like "We now know that some tardigrades can tolerate being frozen to -272.8 °C". But any ...

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