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51 votes
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Why are prions in animal diets not destroyed by the digestive system?

Proteases are enzymes in your digestive system that help break down food, acting like molecular-sized scissors that cut up proteins. Proteases have clefts, or subpockets, into which proteins fit, ...
Alex Reynolds's user avatar
47 votes
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Why are sugars in whole fruits not digested the same way sugars in juice are?

Sugars in 100% natural fruit juices are chemically the same as in whole fruits. They mainly include glucose, fructose and sucrose: Apple nutrition data (expand the carbohydrate section) Apple juice ...
Jan's user avatar
  • 8,079
33 votes

Would fewer cows mean less methane emission?

Couple of thoughts: (The OP's article is a low quality source of info with either an interview taken out of context or an inappropriately vague or under-informed interviewee. Reasons why will become ...
theforestecologist's user avatar
27 votes
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How can birds disperse seeds when they are able to digest them?

Birds may indeed digest seeds under conditions of rest. It has been postulated that almost all current knowledge on mechanisms of internal seed dispersal has been obtained from experiments with ...
AliceD's user avatar
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25 votes

Why is wombat scat (feces) shaped like cubes?

I'm almost certain that your question is based on the press that Patricia J Yang's research is receiving (e.g., here and here). Yang and her co-authors examined the structure and mechanics of some ...
theforestecologist's user avatar
16 votes
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Why does biomagnification of mercury occur more in large fish?

Bioaccumulation occurs when organisms aren't able to excrete/eliminate/metabolize something as fast as they take it in. The specific circumstance of predators higher on the food chain accumulating ...
Bryan Krause's user avatar
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12 votes
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Why aren't the antibodies in the mother's milk digested by the infant's digestive system?

Demers-Mathieu et al. 1 used ELISA to quantify immunoglobulin concentrations from milk after 2 hours of digestion in the stomachs of preterm-delivered and term-delivered infants. From the abstract: ...
acvill's user avatar
  • 8,296
9 votes

Why is wombat scat (feces) shaped like cubes?

On a more serious note than my comment, and as a supplement to theforestecologist's answer, it's worth pointing out that a cube with rounded corners and edges has larger surface area to volume ratio ...
it's a hire car baby's user avatar
7 votes
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What are the consequences of drinking water with food?

A moderate amount of water while eating will not dilute digestion ...according to Michael F. Picco, M.D. and the Mayo Clinic: There's no concern that water will dilute the digestive juices or ...
Dave Gruenewald's user avatar
7 votes

Why are sugars in whole fruits not digested the same way sugars in juice are?

Drinking the juice without the fruit can easily lead to over-consumption. It is after all harder to eat four apples than drinking 500ml apple juice. As the liver breaks the fructose through ...
Pebermynte Lars's user avatar
7 votes
Accepted

Why is sugar absorbed very fast into the blood stream?

In short, sugars are absorbed quicker than proteins and fats because they pass through the stomach quicker and their digestion is simpler. Sugar can be absorbed through the mouth mucosa when applied ...
Jan's user avatar
  • 8,079
7 votes
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Why can't humans digest dietary fiber when we can digest starch?

"starches are held together with A bonds, dietary fibers are held together with B bonds, and the enzymes only work to break A bonds for X reason" What you wrote here is correct. ...
MattDMo's user avatar
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6 votes
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How does horse extract the energy to needs from a relatively small digestive system?

The digestive system of a horse is by no means small: They have 15 to 21 m (50 to 70 ft) of small intestine, with a capacity of 38 to 45 L. They have a 1.2 m (4 ft) long caecum that holds 26 to 30 L. ...
Harry Vervet's user avatar
  • 2,482
6 votes

Human Digestion of Cellulose?

This isn't a complete answer, but searching Google Scholar for "Fibrobacter succinogenes human" I found this paper: The cellulose-degrading microbial community of the human gut varies according to ...
Oosaka's user avatar
  • 3,245
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

Why is livestock bad for the climate?

Short answer Two factors playing a role in livestock's contribution to the greenhouse effect have to do with methane being a more potent greenhouse gas and the fact that the conversion of plant ...
AliceD's user avatar
  • 52.4k
5 votes
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Betaine HCl stomach pH

Betaine HCl (trimethylglycine) was present in over the counter "stomach acidifiers" but the US FDA says there is no evidence for its efficacy and has banned its use for this indication (source: US FDA)...
Bryan Krause's user avatar
  • 45.7k
5 votes
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Can you eat enough to make your stomach explode?

Here's a simple cross-section of the stomach (from here): The stomach accomplishes much of its function by mechanically breaking down the swallowed food particles and mixing them with acid and ...
MattDMo's user avatar
  • 15.3k
5 votes

Can Fluoride be absorbed into the blood from within the mouth without swallowing?

Although I'm having a hard time finding a source that provides specific information on fluoride in toothpaste, this review explains that fluoride is most readily absorbed through intestinal epithelia ...
Forest's user avatar
  • 1,879
5 votes

Is sugar absorbed into the bloodstream through the walls of the mouth?

Simple sugars such as glucose, fructose and galactose will be absorbed. They are most probably transported by a common carrier, which is why if you present both glucose and galactose, the presence of ...
S Pr's user avatar
  • 6,222
5 votes
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Why is livestock bad for the climate?

Short Answer I'll address the first two of your three sub-questions: Livestock are not climate neutral because different processes of the carbon cycle create different carbon-based molecules at ...
theforestecologist's user avatar
4 votes
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How Anopheles crop doesn't digest gametocytes of P. vivax?

Short Answer: Nothing prevents it, most Plasmodium (gametocytes/gametes/zygotes/ookinetes) are killed. Background: After lots of search, I finally found a definite answer about this. According to ...
another 'Homo sapien''s user avatar
4 votes

How Anopheles crop doesn't digest gametocytes of P. vivax?

Disclaimer: I am trying to answer the question without finding any academic research on the topic. So, appreciate hypotheses and feel free to point out mistakes. Short Answer : Co- Evolution Broad ...
Mockingbird's user avatar
4 votes
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Is aquafaba readily digestible?

Much of it is not readily digestible. According to this chemical analysis: Finally the results presented here also indicate that the amount of digestible carbohydrates in aquafaba is minimal. For ...
Jason C's user avatar
  • 638
4 votes

Digestion of milk in humans

Short answer My best bet is D) Background A) seems incorrect as lipases break down fats. However, one has to realize there quite some fat in milk (up to 3.5% in untreated milk). Digestive lipases in ...
AliceD's user avatar
  • 52.4k
4 votes
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How do bile salts affect lipase activity?

Let us first clear out some basic concepts regarding lipase, colipase and bile salts. The pancreatic lipase has an optimum pH range of about pH 8.0 (Worthington). This can be understood easily by Le ...
another 'Homo sapien''s user avatar
4 votes
Accepted

Enzymes and Digestion

I suspect that the question reveals an incomplete understanding of enzymic catalysis and could more generally be rephrased as "If enzymes just speed up biological reactions, what makes the reactions ...
David's user avatar
  • 25.8k
4 votes

Is there evidence to suggest that nutrients in vitamin capsules are not as readily absorbed as the same nutrients in whole foods?

The answer probably varies for different nutrients. An informal article by ConsumerLab.com indicates that many vitamins are better absorbed from natural sources, but a few are actually more readily ...
augurar's user avatar
  • 1,584
4 votes

Carbohydrates in acidic stomach

As for the digestion of fats there are two digestive enzymes active in the stomach: Lingual lipase (produced with saliva) Gastric lipase (produced in the stomach chief cells) Both have activity ...
adjan's user avatar
  • 2,106

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