51
votes
Accepted
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, ...
- 5,590
47
votes
Accepted
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 ...
- 8,104
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 ...
- 30.3k
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 ...
- 30.3k
16
votes
Accepted
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 ...
- 46.5k
12
votes
Accepted
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:
...
- 8,326
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 ...
- 199
7
votes
Accepted
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 ...
- 2,046
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 ...
- 171
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 ...
- 8,104
7
votes
Accepted
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. ...
- 15.3k
7
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 ...
- 52.6k
7
votes
Accepted
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 ...
- 30.3k
6
votes
Accepted
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.
...
- 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 ...
- 3,253
6
votes
Accepted
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
...
- 1,307
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 ...
- 1,879
5
votes
Accepted
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)...
- 46.5k
5
votes
Accepted
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 ...
- 15.3k
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 ...
- 6,272
4
votes
Accepted
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 ...
- 638
4
votes
Accepted
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 ...
- 14.1k
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 ...
- 584
4
votes
Accepted
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 ...
- 14.1k
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 ...
- 2,106
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 ...
- 52.6k
4
votes
Do mosquitos excrete blood?
When mosquitos feed on blood they release water droplets, this is so they can condense the amount of nutrients from the blood but dispose of the unnecessary water weight. This act of releasing excess ...
- 171
4
votes
Accepted
Why does drinking milk lead to increased fractures?
The authors suggest a reason in their abstract:
Given the observational study designs with the inherent possibility of residual confounding and reverse causation phenomena, a cautious ...
- 12.3k
4
votes
Do sharks fart?
Excellent question. Via Southern Fried Science: According to Daniella Rabaiotti, a postdoctoral researcher at the Zoological Society of London, sand tiger sharks are the only shark known to fart.
They ...
- 226
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