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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66 views

How are ions 'pumped' across a membrane during electron transport?

A number of sites (including this one) that provide descriptions of photosynthesis state that high energy electrons 'pump' ions across a membrane. What is the actual 'pumping' mechanism? I've looked ...
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0answers
8 views

How to Stabilize Histamine Surges in Exercise of MD/DMII?

I am studying how to stabilize histamine surges/effects without antihistamines in exercise of Metabolic Syndrome (MD) and Diabetes Mellitus II (DMII). Generic/simplified case: Symptoms in exercise: ...
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0answers
10 views

How to increase the shelf life of yogurt..?

I wonder though bacteria is still present in it and continue to convert lactose into lactic acid then why does not packed yogurt becomes sour? How these companies increase the shelf life of yogurt..?
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0answers
17 views

Maintenance of muscle mass due to doping anabolic substance [closed]

Take the case of an athlete looking to increase his muscle mass, it will take anabolic doping substances during a certain period of time then it will stop. Is it possible for this athlete to maintain ...
3
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1answer
210 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?
5
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1answer
2k views

What does vitamin B6 and B12 absorption depend upon?

I'm looking at my question about homocysteine metabolism and am doing a followup inquiry into vitamins B6(Pyroxidine) and B12(Cyanocobalamin). I've found this interesting bit about vitamin B12 and am ...
2
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1answer
30 views

Can lactate be created in ketosis?

After looking at Cori Cycle (from wikipedia) I have a question about how the lactate can be produced in ketosis. According to this article: in a low-glucose state, where the body senses that ...
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0answers
13 views

What's the highest glucose concentration (in mM) anywhere in the human body (tissue, capillaries, tumor microenvironment, etc.)?

Glucose blood levels are around 5mM, or 10mM after meals. In capillaries these levels can rise by about 40 %. I haven't found measurements of glucose concentration in tissues, or in extracellular ...
9
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1answer
104 views

Statistical method for characterizing the relationship between body mass and metabolic rate

There is a dataset that contains body mass ($x$) and metabolic rate ($y$) from many different organisms. It is common to fit the data to the model of the form $y=ax^b$ and estimate the parameters $a$ ...
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0answers
11 views

Could there be some safe, hypothetical way of turning on and of thermoregulation?

This is something I thought of with the whole artificial gill concept. Could a modification to the brain/nervous system allow a human to turn off their thermoregulation in air/water of the right ...
2
votes
1answer
39 views

Does the body prioritise the use of available sugar before fat?

Let's say you eat a very unhealthy snack that contains 90% sugar and 10% fat. Would somatic cells not start using the fat for energy until all the sugar is used up? Does the body not use fat at all ...
4
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1answer
55 views

How can I obtain a computer readable model of Dr. Gerhard Michal's biological pathways map?

I want to run simulations of various metabolic pathways – the project could end up becoming quite large, and having a machine readable chart would make thing a lot easier. Does anyone know if there is ...
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0answers
10 views

Bilirubin metabolism and UGT1A1 inhibition in human vs. monkey?

In human UGT1A1 seems to be the only relevant enzyme to glucuronidate unconjugated bilirubin into excreted forms. Is the pathway the same for e.g. the Cynomolgus monkey (Macaca fascicularis) in vivo? ...
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0answers
21 views

Anaerobic nutrient expenditure

Doing some research into different forms of exercise and energy systems and I realized something odd about the way we talk about energy. When we eat, we take on macronutrients that are broken down ...
3
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0answers
17 views

Cellular demand for antioxidants

Antioxidants such as ascorbate and glutathione serve to inactivate radicals and counteract spontaneous oxidation reactions, such as unwanted disulfide bonds in proteins. These systems are cycles, ...
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0answers
19 views

Need to solve a “pseudo-metabolic” network for rates

following problem: I have data on a certain complex association network (from monomers 1 ... 8 to complexes of all combinations, such as, 12 ... 13 ... 18 and so on until 12345678, so that I know ...
3
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0answers
22 views

Are there animals that can deliberately manipulate their metabolism, apart from hibernation?

Are there animals that can slow down their metabolism deliberately? I know that hibernation would be one mechanism, and maybe being cold-blooded, but I was wondering if there was maybe an animal that ...
-2
votes
1answer
87 views

What is ATP and why is it said to be a source of energy? [closed]

Is ATP a molecule or a kind of energy. When I studied the active transport, it's said the ATP would release energy to change the carrier protein shape. So confused. Thanks for your help.
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0answers
10 views

Is it possible to stimulate the EPOC process?

On Wikipedia, EPOC is defined as: Excess post-exercise oxygen consumption (EPOC, informally called afterburn) is a measurably increased rate of oxygen intake following strenuous activity intended ...
14
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3answers
360 views

In a tumor, why hypoxic regions have access to glucose?

The Warburg effect is ubiquitous in cancer. It consists of the upregulation of glucose uptake, glycolysis, and subsequent lactate secretion, sometimes by over 200 times, in cancer cells as compared to ...
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0answers
13 views

Bilirubin metabolism pathway in non-human primates (NHP)?

In human UGT1A1 seems to be the only relevant enzyme to glucuronidate unconjugated bilirubin into excreted forms. Is the pathway the same for e.g. the Cynomolgus monkey (Macaca fascicularis) in vivo? ...
11
votes
3answers
406 views

During starvation, does the human body do anything to prioritize which organs receive nutrients?

When food is scarce, the body slows its metabolic rate to conserve energy. Are there any other systems or processes that prioritize which organs receive nutrients?
10
votes
3answers
846 views

What is the purpose of gluconeogenesis?

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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0answers
23 views

Why does our body regulate metabolic processes using the thyroid hormone?

People with hypothyroidism do fine when taking medication containing their daily dose of thyroid hormone. This means that the signaling function of the thyroid hormones is, in principle, unnecessary. ...
2
votes
1answer
40 views

What are calories and how to burn them? [closed]

What exactly is a calorie? When burning calories, do we always lose fat? I have tried many apps to measure calories, do they give exact amounts? How many calories should be taken a day?
2
votes
1answer
47 views

Why does protein kinase C activated by different means have different effects?

I could be way off base but I think I remember learning that Protein Kinase C has some effects when activated by one pathway and other effects when activated by another. How does this happen? Is it ...
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0answers
21 views

If chylomicrons can not get into the capillaries, how do they supply to tissues?

The transport of chylomicrons is into the lacteals mainly because they are too big to get into the capillaries and yet they later supply triglycerides in the extra hepatic tissue by traversing in the ...
2
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1answer
37 views

How many calories do gut bacteria burn?

It has become well-accepted that microbiota of the gut (a.k.a. gut bacteria) consume calories that are ingested and can have significant effects on energy metabolism in humans. For example, if you ...
1
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1answer
31 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 ...
3
votes
2answers
65 views

Can bacteria metabolize fatty acids for fuel?

I'm not a microbiologist, but rather a physiologist curious about microbial metabolism. Much like humans bacteria can utilize glucose, but when it comes to long chain, medium chain, or short chain ...
3
votes
2answers
121 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 ...
8
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2answers
72 views

Is there a metabolic pathway that generates methanol?

I've been looking for help topics about methanol in metabolism. Specifically, I wish to know what is a common dietary component that generates methanol following metabolism and comment on its ...
3
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0answers
22 views

Are there bacteria that respire anaerobically in aerobic conditions?

There are facultative aerobic bacteria that switch to aerobic respiration in an aerobic state, but are there any organisms that would still perform anerobic respiration even when shifted to aerobic ...
2
votes
0answers
21 views

What is the function of CETP?

I read up that CETP transfers cholesterol from HDL, which collected it from tissues, to VLDL. This VLDL is then sent back to the tissues, ultimately forming LDL internalised by cells. What is the ...
2
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0answers
28 views

What is the rationale behind reverse cholesterol transport?

Reverse cholesterol transport is transport of cholesterol from the tissues back to liver/VLDL. My question is why do the tissues have this extra cholesterol in the first place? Why would you ...
2
votes
1answer
108 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
votes
2answers
728 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 ...
3
votes
1answer
63 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
20 views

What is the site on an enzyme that binds either exitatory or inhibitory molecules? [closed]

A site on an enzyme where either exitatory or inhibitory molecules can bind is called a(n): A) electron transport site B) active site C) coenzyme D) metabolic pathway E) allosteric site If you ...
7
votes
2answers
623 views

Why are there so many medicinal plants?

Question Quite a few plant species can be used for medicinal purposes wiki. As an example, Filipendula ulmaria is rich in acetylsalicylic acid (aspirin). An allele that produces a substance which is ...
15
votes
3answers
4k views

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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0answers
38 views

Are cold-blooded animals more energy efficient than warm-blooded animals? [duplicate]

When cold-blooded animals extract energy from glucose, do they do so in a more efficient manner than warm-blooded animals? If they aren't producing heat as a by-product, that would suggest that ...
1
vote
1answer
36 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 ...
2
votes
0answers
29 views

Why lactate inhibits growth (or enhances death rate)?

Extracellular lactate tends to inhibit cellular growth or enhance cell death. This happens in the vicinity of tumors and in cell cultures. See for example this reference: Ozturk, Sadettin S., Mark ...
9
votes
3answers
483 views

What happens if a non-diabetic receives an injection of insulin?

If a person without diabetes or any diabetes-related issues receives an injection of insulin, what happens? Would the blood glucose level drop or does the body naturally compensate for the added ...
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0answers
18 views

Glycoprotein hormones metabolism

Why do the carbohydrate groups in glycoprotein hormones decrease the rate of metabolism? And increase the half-life?
2
votes
1answer
25 views

Where does the lactate produced by tumors go?

Tumors are known to burn glucose and secrete lactate (this is known as the Warburg effect). Where does this lactate go? Does it steadily accumulate in the neighborhood of the tumor? This doesn't ...
6
votes
2answers
327 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 ...
0
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0answers
22 views

Diffusion coefficients of glucose in mammal tissues?

Where can I find estimates/experimental measurements of the diffusion coefficient of glucose in mammal tissues? Specefically I mean the inter-cellular space. I'm not looking for a specific tissue, so ...
2
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3answers
7k 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 ...