Questions tagged [metabolism]

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

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Is Acetyl-CoA ever transported out of the cell, and in that case how?

Acetyl-CoA is sometimes formed as a result of protein katabolism. Certain cells (in the muscle for instance) can't use Acetyl-CoA to synthesize fatty acid. If there is no immediate need for energy, ...
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Why are 6 turns of the Calvin cycle needed to make one molecule of glucose?

I‘ve read that 6 turns of the Calvin cycle are required to make 1 glucose molecule. But, 3CO2 and 3RuBP are used in one cycle and 6 triose phosphate is produced. Only 5 triose phosphate molecules are ...
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How can we explain that glucose at its concentration less than a Km for the transporter enters the peripheral circulation?

I'm studying biochemistry from Kaplan's book. In it, I found the following paragraph in the topic on glucose metabolism: "GLUT 2, a low-affinity transporter, is in hepatocytes. After a meal, ...
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Do quantum mechanical effects such as uncertainty, tunnelling and entanglement play role in the electron transport system of respiration?

The electron transport system of aerobic respiration involves an extensive pathway of electron and proton transfer from one centre to another. Now, since they are quantum mechanical particles, shouldn'...
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Why does ATP act as an allosteric inhibitor of glycogen synthase?

Why is ATP an allosteric inhibitor of glycogen synthase? Wouldn't high levels of ATP in the cell mean that the cell has sufficient energy, and in this case wouldn't excess glucose be stored as ...
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Is there a function for urea in sweat?

In ureotelic organisms, ammonia is converted to urea for excretion primarily in the liver and, to a lesser extent, in the kidneys. However, sweat also contains trace amounts of urea. Is this small ...
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How does exercise cause weight loss if the corresponding chemical reactions have the same mass on the LHS and the RHS?

How does weight loss take place in the body during physical activity, given that the corresponding chemical reactions would have the same mass on the left hand side and the right hand side?
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Isolated mitochondria in glucose rich solution, what happens to ATP generation?

I'm taking intro to biology course this year, and I was thinking about this question. Isolated mitochondria were placed in a glucose rich solution. (With ADP and Pi). How would this affect the ATP ...
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Concentration of active ingredient

For some time now, I have been wondering why, when a tablet is taken, the concentration of active ingredient undergoes an exponential decrease after the maximum concentration value in the blood is ...
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What actually kills a plant that requires winter dormancy if it is kept indoors all year?

In bonsai practice, beginners will commonly purchase a juniper (often Juniperus procumbens 'Nana'), which is an outdoor tree, and keep it inside all year. The tree invariably dies. It is commonly ...
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Why is fructolysis independent of glycolysis?

In glycolysis, glucose is converted to fructose-6-phosphate before further breakdown. However fructose, instead of being phosphoryated to fructose-6-phosphate by glucokinase (and thereafter to ...
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Maximum Allometry of aquatic mammals omitting Kleiber's Law

As far as I understand, blue whales cannot get any physically larger due to the extremely demanding caloric intake it has on consuming large quantities of krill, not due to any other physiological ...
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Production of plant derivatives using genetic engineered micro-organisms

I saw a Thought Emporium video where spider silk was produced by genetically modifying yeast. I have also read about companies making vanillin (vanilla flavour) using this technique. I am curious to ...
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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 ...
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What terms or concepts are used to describe the morning metabolic phenomenon involving glucocorticoids, glucose, and blood pressure?

A recent conference report described using a vaccine-based strategy to blunt a surge of high blood pressure that occurs between 5 and 8 a.m. Apparently most heart attacks and strokes occur during ...
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Why hypothyroidism causes body ache?

In the condition of hypothyroidism the Thyroid Stimulating Hormone level is high in individuals. What signalling/metabolic pathway mediates this sensation of pain which is mostly experienced in feet ...
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How is the glycemic index computed from a blood sugar curve?

The definition of the glycemic index is often given as the area under curve (AUC) of their two-hour blood sugar response. However, it's essentially meant to be a measure of whether food causes a fast ...
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Why is transferrin saturation so low?

Transferrin Saturation (TS) is a common laboratory test and its values can be used to diagnose a variety of medical conditions. In healthy humans, and I assume it is the same for other species, TS is ...
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How do cellular conditions change the Gibbs free energy of a reaction?

How do cellular conditions change the Gibbs free energy of a reaction? Taking glycolysis as an example, how exactly would cellular conditions affect the free energy released from this reaction?
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What is the energetic costs in KJ/g NH3 for nitrogenase fixation

What is the energetic costs in KJ/g NH3 for nitrogenase fixation. I want to compare Haber-Bosch vs nitrogenase. How would I force the biological stochiometry of 8e- electrons into an energy quantity. $...
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Do all anabolic reactions involve condensation?

I know that condensation is one example of an anabolic reaction (building macromolecules from monomers), but do all anabolic reactions involve condensation? Or is there an example of an anabolic ...
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What is a metabolite? [closed]

I am a mathematician and work on metabolic networks as networks. But I could not find a proper definition for a metabolite? Are they organic molecules? can a gene or a protein also be a metabolite?
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Relation/difference between metabolism and cellular organisation

In the highlighted paragraph from NCERT textbook, they mention that cellular organisation is the defining property of life forms while metabolism without exception is also the defining property of ...
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Apparent paradox in Glucagon action

Glucagon stimulates glycogenolysis and gluconeogenesis, thus increasing the plasma glucose concentration — so that tissues get enough glucose in the fasting state. However glucagon also inhibits ...
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Why are children more active than adults?

I have observed that children are usually more active than adults. For example, in the morning they get up and start playing, they have their lunch and get up and start running, while as adults they ...
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Do identical twins have the same metabolism rate at birth? [closed]

Will monozygotic twins defecate at the same time if fed at the same time during the first weeks of life? They should have the same genetics (and epigenetics) since they are monozygotic and the same ...
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Glycogenolysis & Gluconeogenesis

Is glycogenolysis and Gluconeogenesis is the same in the terms of product formed? This doubt arrived when I was attempting true & false and the question was Glucocorticoids stimulate ...
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Do Termites and Silverfish metabolize cellulose the same way?

I am fascinated with silverfish and would like to understand more about their metabolism. I learned that they can survive on a diet of cotton which is nearly pure cellulose. Do they metabolize ...
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mitochondria has more activity or the numbers of them are more?

If a cell is needing energy more than the other cells, does it mean that it has more mitochondria or the activity of them is more?
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Quantification of various amino acids from bacteria?

I would like to characterise how much of various (uncommon) cytosolic amino acids are produced in bacteria, and was wondering if there are good suggestions of how to go about doing this. I know that ...
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Reverse oxidative phosphorylation?

I noticed that all of the cellular energy production methods that I covered have a fixed ratio of ATP to NAD(P)H out. For example, in the combined process of glycolysis, pyruvate oxidization, and the ...
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Should I consider [H+] as substrate in MCT transport equation?

I'm trying to model the transport of lactate in cells (in both direction via Monocarboxylate transporters): [Lactate]intra + [H+] <----> [Lactate]extra + [H+] I found some data on kinetics of ...
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How does exercising/starved muscle import glucose (released by liver)?

Adrenaline releases glucose from the liver during sport or if starved. This glucose goes to the blood through GLUT2 transporter. But how does it get transported into the muscle cells? GLUT4 is the ...
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Can muscles remake pyruvate from lactic acid, or does it have to go to the liver in the Cori cycle?

When the muscle is exercising, and only anaerobic respiration is done, pyruvate -> lactate to regenerate NAD+. Lactate is then transported out of the muscle and into the liver, to regenerate glucose, ...
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What relation do glycerol-3-P DH and acyl-CoA DH have with Complex II of the ETC?

I am sorry if this may be a purely definitional/nomenclature question. Complex II of the electron transport chain (ETC) would be succinate dehydrogenase, transporting electrons to ubiquinone (and ...
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What makes the cytoplasm a reducing environment?

It is known that the cytoplasm is a "reducing" environment, where disulfide bonds cannot form (will soon be reduced to 2 cysteines) [I'm not putting a link as this is a fact in many biology textbooks]....
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Does an FAD:FADH2 ratio exist in the cytoplasm? (similar to NAD+:NADH ratio?)

I have learned about a lot of enzymes/proteins which are covalently bound to FAD, and use this as an oxidising agent. In vivo, FAD is (almost) always protein bound (very low concentrations of free FMN/...
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Is there any other sources of hydrogen carriers for the Electron Transport Chain other than the 3 main metabolic pathways?

I am learning about the 4 main metabolic pathways for cellular respiration. I learned that NADH and FADH2 hydrogen carriers are essential in the Electron Transport Chain, because they deposit their ...
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Do plants take in the same amount of CO2 as they release?

There are many claims in the media that trees remove more carbon dioxide form the atmosphere than they release back into the atmosphere. By what chemical pathway can this occur? The law that matter is ...
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Why/How do Cyanobacteria Produce Toxins?

I've been doing some research on the versatility of nitrogen-fixing cyanobacteria, particularly of the genus Anabaena, and I often run into safety hazards and have to add extra steps to my procedures ...
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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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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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Are there any known microbes capable of living in almost pure carbon dioxide?

Some bioengineering is investigated in high carbon dioxide environments. Are there any microbes like bacteria or Archaea capable of living and multiplying in such environments?
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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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