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26 votes
Accepted

How can a drink contain 1.8 kcal energy while 0 g fat/carbs/protein?

The list of ingredients on the can mentions "Zuckerkulör," which is caramel colour, which can have 2 kcal/g, according to one producer. Next, there is "Citronensäure," which is citric acid, which can,...
Jan's user avatar
  • 8,089
19 votes
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Why is the retention of ability to synthesize non essential amino acids of negative survival value?

It’s a very dubious argument in my opinion. Whenever I see a question on this list arguing that higher organisms could save energy and DNA by such-and-such a hypothetical construct I want to scream. ...
David's user avatar
  • 26.3k
12 votes
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How long do fishes survive in a milk environment?

I can't support this answer with scholarly articles. But it's an interesting question if you think of milk as highly polluted water. Water from a tap (which is what goldfish usually live in) is '...
anongoodnurse's user avatar
10 votes
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How a vegan can consume all the needed varied proteins / amino acids?

Proteins are made up of amino acids. It isn't particular proteins that are necessary in diet, but particular amino acids. For humans, these come primarily from breaking down the proteins in foods we ...
Bryan Krause'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
  • 5,725
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
  • 46.2k
8 votes
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How does zoo and laboratory animal feeding work?

I volunteered for 3 years at a large mammal laboratory where we diligently tracked the weight and caloric intake of each of our animals. Diets were weighed out each morning and total calories could be ...
Megan McE's user avatar
  • 216
7 votes

What do bloodsucking animals actually feed on?

Lets find out how much calories are there in the blood. I am using this site for main reference, but will also add more references where needed. But before that, we should know that one donation of ...
another 'Homo sapien''s user avatar
7 votes
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Nutrient limitation in terrestrial and freshwater ecosystems

The traditional explanation for this is that nitrogen compounds are more mobile than phosphorus compounds. As a result, nitrogen is more likely to flow through terrestrial ecosystems and accumulate in ...
Nathan's user avatar
  • 176
6 votes

Where do mushrooms get their energy from?

Mushrooms are the fruiting bodies of fungi. Fungi get their energy by decomposing dead or decaying organic material, such as fallen leaves or dung. Some background: spores of fungi germinate forming ...
Daan's user avatar
  • 371
6 votes

Is there any organism that is born with all the nutrients and resources needed for their entire lifetime?

You may need to clarify your question: As written, this would be the biological equivalent of a perpetual motion machine. No such organism could reproduce without either violating the first and second ...
Alex Reynolds's user avatar
6 votes
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Do humans emit more carbon through respiration or defecation?

The short answer In a comparison between exhaled and faecal carbon, exhaled carbon wins. The long answer Warning: Assumptions, approximations and averages ahead. Calculating faecal carbon excretion ...
Adhish's user avatar
  • 1,307
6 votes
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Do cochineals ("scale bugs") form aluminium complexes themselves? Where do they get such large quantities so quickly and how do they handle it safely?

Aluminium moves within plants as a complex with ligands such as oxalate, malate, and citrate. Plant cells also hide the aluminium (and other junk) in vacuoles. That is most likely the immediate source ...
Polypipe Wrangler's user avatar
6 votes
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Special food for big cat cubs?

Cat food has a specific a composition, because the suppliers have to keep their products consistent and they are designed to meet the nutritional needs of indoor cats. I do believe that kittens have a ...
Frieke's user avatar
  • 1,127
6 votes
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Is it viable to make liquid potassium ferilizer through dissolving very small amounts of potassium chloride in water

the issue here is the chloride not the potassium. Potassium chloride is very soluble in water. but you could be killing your crops/garden when you spray it on. Most plants do not tolerate much ...
shigeta's user avatar
  • 28.3k
6 votes

Why is the retention of ability to synthesize non essential amino acids of negative survival value?

The passage is saying that if you get enough of a nutrient in your diet, you don't need to synthesize it. If you don't need to synthesize a nutrient, you don't need to waste energy on the machinery to ...
Bryan Krause's user avatar
  • 46.2k
5 votes
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What is the diet preference of American cockroaches?

American cockroaches (Periplaneta americana) are omnivorous and opportunistic feeders, and as a result, they eat a large variety of foods. They will eat almost anything. Favorite foods: They are ...
theforestecologist's user avatar
5 votes
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How is a substance classified as a vitamin?

1) Vitamin D is a bit of an umbrella term that actually refers to a whole group of related molecules. One of these, vitamin D$_3$ (cholecalciferol) is formed spontaneously from ergosterol in the ...
Roland's user avatar
  • 5,725
5 votes
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Why does protein have 4 calories per gram?

Ultimately, the 4 kcal/g numbers come from calorimetry. That is, scientists take a small amount of glucose or protein, put it in a device which burns the material and figures out how much energy is ...
R.M.'s user avatar
  • 1,554
5 votes
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Why are dietary recommendations for methionine consumption combined with cysteine?

In humans, cysteine can be synthesized from methionine and tyrosine from phenylalanine (note that the reverse pathways do not occur). Because their synthesis requires essential amino acids and the ...
canadianer's user avatar
  • 17.8k
5 votes
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What are the bare minimum nutrients required to survive as a human?

Essential nutrients include (NutrientsReview): Water 9 amino acids: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, tryptophan, threonine, valine 2 fatty acids (alpha linolenic and ...
Jan's user avatar
  • 8,089
5 votes

What vitamins exist for other animals but not humans?

The best example I can think of is taurine, which is a non-proteinogenic amino acid. Taurine is "conditionally essential" for humans1, but essential for cats2,3. References: 1: Stapleton, P. P., ...
tyersome's user avatar
  • 5,598
5 votes
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What is the cause of a protuberant belly in kwashiorkor?

The Gastroenterology paper you cite doesn't mention distended bellies at all. There is no dispute that fatty liver is a symptom of kwashiorkor. But the Wikipedia article makes it quite clear that ...
Lawnmower Man's user avatar
4 votes

How does a garlic clove thrive inside a closed refrigerator?

Your garlic was likely purchased as a bulb, not seed, and stored in the fridge. The garlic 'clove' is not frozen, so your fridge readily mimics underground conditions in the temperate late winter or ...
Plantaloons's user avatar
4 votes
Accepted

Can I tell my antioxidants intake based on nutrition facts labels?

Well yes, you could get this information from food labels, since the recommended daily intake of vitamins is well established. But there is really no need to worry about dietary "antioxidants" (...
Roland's user avatar
  • 5,725
4 votes
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Essential amino acids

Bacteria and plants are able to synthesize all amino acids, as they are capable of nitrogen fixation. If animals eat plants, they get the essential amino acids needed for their proteins. Humans get ...
SeRe's user avatar
  • 425
4 votes
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Spruce growing high up in a maple trunk: Can a partially rotted trunk completely sustain another tree?

Note This answer makes the presumption that the crotch in the maple's trunk is indeed a breach through its bark, and does reach the inner woody tissues. The heartwood of most trees consists of the ...
can-ned_food's user avatar
4 votes

Spruce growing high up in a maple trunk: Can a partially rotted trunk completely sustain another tree?

Well, holes in rotting trees are not only going to contain rotten tree matter (aka compost :p), but they will also slowly gather fallen leaves, dead insects, dirt, dust and other debris. Even ...
theforestecologist's user avatar
4 votes

How do we know we have to use the mouth for eating and drinking?

Quite frankly we don't, eating is instinctual, only later as we grow up do we learn why we do it. It is reinforced with learning later but that is a minor effect. Eating is one of the most basic of ...
John's user avatar
  • 14.9k

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