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22 votes
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Is lysergic acid diethylamide (LSD) metabolized in the body?

Short answer LSD appears to be enzymatically broken down in the liver. Background First off, hormones do not break down anything; enzymes are the work horses that mediate metabolism. According to a ...
AliceD's user avatar
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20 votes
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Is agriculture really a net contributor of greenhouse gases?

The issue is that it is not always a cycle, when you drain wetlands or burn forests to make more farmland that's not a cycle that is permanent change. A change that can continue having effects for ...
John's user avatar
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12 votes

Recycling of nitrogen in hibernating mammals

Summary The hibernating animal in which the recycling of nitrogen has been best studied is the ground squirrel. Recent studies in this species by Regan et al. (Science (2022) 375, 460–463) have ...
David's user avatar
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11 votes

What is the ultimate source of ADP/ATP in humans?

Phosphorus is a very common nutrient, found in high levels in proteins, which are in such foods as milk and milk products, meat, beans, lentils, nuts, and grains, especially whole grains. Phosphorus ...
MattDMo's user avatar
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11 votes
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Origin of the biochemical term, Pi (inorganic phosphate)

This terminology is at least as old as September 1944 when Enzymatic Synthesis of Acetyl Phosphate Journal of Biological Chemistry 155, 55-70 was published by Lipmann, which says: Inorganic ...
DavePhD's user avatar
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10 votes

What is the brain's preferred energy source? Glucose or ketones?

First of all, for those readers with less knowledge of the general principles of biology, I want to state an important, even if obvious, point: The brain doesn't "prefer" anything. Despite ...
Don_S's user avatar
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10 votes
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Does Glycolysis produce lactate, or pyruvate?

I think you will find all text books (e.g. Berg et al. Ch 16) describe glycolysis as the conversion of glucose to pyruvate, as this is how it has been defined and considered in countless biochemical ...
David's user avatar
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9 votes
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Is palmitic acid really that dangerous?

Let's first clarify some concepts. Free fatty acids, including palmitic acid, are not present in animal tissues (or in the diet) to any large extent; they are esterified with glycerol to from ...
Roland's user avatar
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9 votes
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Effect of cold showers after intense training

Taking cold showers(10-15 ℃) after training or workout have many benefits: It helps in lowering the damaged tissues temperature by constricting blood vessels. Cold helps numb nerve endings which ...
Mesentery's user avatar
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9 votes
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How can grass-fed livestock generate fat?

Short answer Plants typically store energy in the form of starch. Animals, including livestock and humans for that matter, can digest starch, metabolize it into acetyl-CoA and turn it into fat. ...
AliceD's user avatar
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9 votes

Why is carbon dioxide produced in alcohol fermentation but not in lactic acid fermentation?

Glycolysis needs a steady supply of NAD+ to happen - this is the driver for the anaerobic oxidation to lactate and ethanol, although this is energetically much less favorable than the complete ...
Chris's user avatar
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9 votes
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How much energy does a small spider expend per day just waiting for its web to vibrate?

Short answer Approximately 240 J on a daily basis. Background Ballesteros et al. (2018) modeled basal metabolic rates of insects. They reckoned that endotherms, like insects, basically use energy ...
AliceD's user avatar
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9 votes

Does food lose some of its mass in form of energy during metabolism?

Physics answer that is a bit silly If you want to be real technical about physics, mass and energy are the same thing, so any chemical bond that has some energy and is broken results in a change of ...
Bryan Krause's user avatar
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9 votes
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Why are children more active than adults?

This is a great question! As I see you are new and you have explained within the comments above that you haven't studied biology much I will keep the explanation short and sweet. Young children have ...
James's user avatar
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8 votes

How Does Green Tea Increase Metabolic Rate?

Interesting question! Green tea increases metabolic rate of body because it contains antioxidants known as catechins1. Catechins are actually polyphenol flavonoids, and have been shown by Wang et al ...
another 'Homo sapien''s user avatar
8 votes

Is lysergic acid diethylamide (LSD) metabolized in the body?

LSD is metabolized in the liver in humans by enzymes of the Cytochrome P450 hemoprotein. The specific enzymes are CYP3A4 and CYP2D6. CYP2D6 is generally regarded as non-inducible (meaning there ...
Drunken Code Monkey's user avatar
8 votes
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When you lose weight, how does the mass exit your body?

as CO2 and water in respiration sugar (or fat) is combined with oxygen to produce energy(ATP and heat), water, and CO2. fats are converted to Acetyl Co-A just like glucose is, the rest of the ...
John's user avatar
  • 14.7k
8 votes

A biological system to measure time

There are lots of biological clocks, or clocks made of biological components. The circadian clock is an important, though complicated, example. There are excellent engineered clocks that form some of ...
Raghu Parthasarathy's user avatar
7 votes

Why is the brain dependent on glucose?

I want to present another (possibly more practical) approach towards this phenomenon. Lets begin with amino acids as alternatives. Amino acids, apart from being a source of toxic ammonia, are also ...
another 'Homo sapien''s user avatar
7 votes
Accepted

Violation of the law of energy conservation between photosynthesis and respiration?

The Fallacies in the argument The question contains two main fallacies (some would say sleights of hand) in the energetic comparison of glucose synthesis from CO2 in the Calvin cycle and glucose ...
David's user avatar
  • 26k
7 votes

Can radiation exposure cause cancer later in life even if no traces of radioactive material are present in the body anymore?

Yes it can, because exposure alone can cause mutations in your genes which is usually the main cause of cancer. For example, when we get exposed to UV light for longer periods of time, we can get ...
Ishi's user avatar
  • 559
6 votes
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Why is glycerol kinase absent from adipocytes but present in the liver?

The short answer to this question is given in the Wikipedia article on glycerol kinase: Adipocytes lack glycerol kinase so they cannot metabolize the glycerol produced during triacyl glycerol ...
David's user avatar
  • 26k
6 votes
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Sex differences in response to food deprivation

There are very few studies about the gender-based differences in response to food deprivation in humans (or at least I didn't find many such reports). In one of the papers, Sodersten et al conducted ...
another 'Homo sapien''s user avatar
6 votes

Why doesn't glucagon promote glycogenolysis in muscle?

Glucagon needs glucagon receptors to have an effect on the tissue or organ in question, and your answer can be found there. Glucagon receptors are found in the liver, like you say, but they're also ...
Jonathan Page's user avatar
6 votes

Reason for conversion of glucose to fructose in glycolysis

Avoiding diffusion is one reason to phosphorylate glucose, the other is that it is removed from the osmotic balance between inside and outside of the membrane, so it can be transported at a high rate. ...
Chris's user avatar
  • 51.7k
6 votes

Is there a point in our life when ALL the atoms from our childhood's body get replaced?

Is there a point in our life when ALL the atoms from our childhood's body gets replaced? No. There is no point where ALL atoms have been replaced. This has been shown by tracing distinct carbon ...
tsttst's user avatar
  • 1,597
6 votes

Was lactose present in the environment before the evolution of mammals?

Preamble This is an answer to the motivation expressed in the question: “…whether lactose-utilising enzymes in bacteria evolved only after the appearance of mammals” rather than that in the title....
David's user avatar
  • 26k
6 votes
Accepted

Why is urea not converted to ammonia in the body?

The answer to this question is quite simply this: The activation energy for the uncatalysed reaction is such that the amount of decomposition of urea in aqueous solution at blood temperature and ...
David's user avatar
  • 26k
6 votes

About the definition of ketogenic amino acid

The fundamental 'problem' with acetyl-CoA is that it cannot be converted to glucose via the tricarboxylic acid (TCA) cycle: a two-carbon compound (acetyl-CoA) enters the TCA cycle, but two carbons are ...
user338907's user avatar
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6 votes
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Apparent paradox in Glucagon action

Summary The apparent paradox is resolved by the fact that not all tissues possess receptors that cause them to respond to glucagon or, more generally, to the same hormone. Where different tissues do ...
David's user avatar
  • 26k

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