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46 votes
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Does 1kg of lettuce have more energy than 1kg of beef?

1kg of beef has more energy than 1kg of lettuce but it isn't directly related to the trophic level energy loss. Given that each level of the food chain has a decrease of 10% of available energy You'...
DKNguyen's user avatar
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38 votes

Does 1kg of lettuce have more energy than 1kg of beef?

The so-called '10% law' is a common, albeit very rudimentary, rule-of-thumb in foodweb analysis. It's commonly attributed to Raymond Lindeman, though he cited a wide range of ratios in natural systems....
bshane's user avatar
  • 3,314
26 votes
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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
9 votes

What makes cherry blossoms so delicious? Does this delicious molecule (or molecules) have some function in the blossom? Does saliva activate it?

There actually is a study in the Nature magazine identifying the volatile (in the sense that they easily evaporate, as most aromatic substances do) organic compounds in cherry flower essential oils (...
KGM's user avatar
  • 323
8 votes

Does 1kg of lettuce have more energy than 1kg of beef?

The (food) energy in 1kg of lettuce or 1kg of beef depends on each's composition, not on its trophic level. Normally we can digest fats, protein and carbohydrates, but other organisms like certain ...
Armand's user avatar
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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
6 votes
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Is it possible that there are unknown vitamins?

Yes, it is possible that there is a vitamin or other essential nutrient that has not been identified so far. Essential nutrient means any substance normally consumed as a constituent of food which is ...
Jan's user avatar
  • 8,089
5 votes

What exactly makes red meat (probably) unhealthy?

The gut microbiome is partly to blame, at least for the associations of red meat consumption with heart disease. Red meat has a high concentration of L-carnitine, which is metabolized by bacteria in ...
acvill's user avatar
  • 8,326
5 votes
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Do violet potatoes contain more or less solanine than normal potatoes?

Seems to be about the same. In Effect of Genotype and Environment on the Glycoalkaloid Content of Rare, Heritage, and Commercial Potato Varieties, Tables 1 and 2 list 60 different potato varieties ...
iayork's user avatar
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4 votes
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Why do protein solutions have to be alkalised in biuret test?

This is probably to prevent precipitation of copper hydroxide (see Itzhaki & Gill, 1964 - they suggest adding dilute copper sulfate slowly to the NaOH solution to avoid this). If you have the ...
Bryan Krause's user avatar
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4 votes

How does zoo and laboratory animal feeding work?

In our university, this is regulated by Institutional Animal Care and Use Committee This organization provides guidance for humane and responsible management of laboratory animals. These protocols ...
aaaaa says reinstate Monica's user avatar
4 votes
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Why is it possible to make yoghourt with lactose-free milk?

Conversion of lactose to galactose and glucose is a part of the bacterial metabolism of lactose. So digested lactose would work. In fact, it should work for all kinds of 6-carbon sugars as lactic ...
WYSIWYG's user avatar
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4 votes
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How is honey not toxic to our epithelial cells?

I'll change my initial comment into a real answer. The human digestive tract has evolved to allow us to be broadly omnivorous, safely consuming a wide range of vegetable, animal, and mineral-based ...
MattDMo's user avatar
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4 votes
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How much heme is in cooked pork and beef; why is cooked pork ("the other white meat") not red?

Yes. Pork has substantially less heme than beef (Cross et al. 2013). As to why the red colour is lost, it is due to the Maillard reaction, by which the iron in the myglobin is oxidized from Fe(II) to ...
rotaredom's user avatar
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4 votes
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Irradiation instead of pasteurization?

Both pasteurisation and irradiation work by killing micro- (and macro-) organisms in food. The two processes are broadly similar and in both cases the objective is to reduce the number of bacteria or ...
arboviral's user avatar
  • 3,354
4 votes
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Cleanliness of cast iron never cleaned between meals

Soap or detergent does nothing to kill organisms. Instead each detergent molecule has two ends, one being hydrophobic (meaning it's repelled by water) and the other end is hydrophilic (attaching the ...
Jude's user avatar
  • 1,136
3 votes

Does 1kg of lettuce have more energy than 1kg of beef?

Note that the decrease in food energy from one trophic level to the next is 90%, not 10%, if only 10% of the energy is actually passed on to the next level. To compare 1 kg of lettuce with 1 kg of ...
Polyhat's user avatar
  • 177
3 votes
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Does baking soda interfere with digestion when cooked into food?

The relationship between acid and bicarbonate is that 1 H+ neutralizes 1 bicarbonate (HCO3) molecule as represented in the following equation: HCl + NaHCO3 --> NaCl + H2CO3 So assuming that the ...
bob1's user avatar
  • 12.5k
3 votes
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Is it possible to produce bread using only microorganisms?

It looks like that yeast has been engineered to produce starch. First of all, the authors had to knock out the genes responsible for the glycogen metabolism pathway (both glycolysis and ...
LinuxBlanket's user avatar
  • 1,313
3 votes
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If overcooked hard boiled eggs show these green sulfide rings, why do scrambled/fried eggs not show this?

Scrambled eggs can change color, but you perhaps haven't run into a batch that shows discoloration. It is the same chemical reaction: Why Scrambled Eggs Turn Green When serving a large group, a ...
Alex Reynolds's user avatar
2 votes
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What chemical test can be used to tell apart meat and plant-based meat?

There are a lot of things you could test for. The thing that come to mind off the top of my head is cholesterol. This will be present in all animal meat, since all animals muscles contain ...
rotaredom's user avatar
  • 2,731
2 votes

Why do we need to grow plants to make food?

We are part of a biological system, and we evolved to be part of it. Plants are the base of that system, and the main means of capturing energy and inorganic compounds and converting them to nutrients ...
Jay Moore's user avatar
  • 827
2 votes

Identifying substance in body fluid (serum, urine)

Dipstick urinalysis? source The urine dipstick has a bunch of squares, each with a chemical analysis ready to go. The dip will semiquantitatively show you what is in the urine. My bet would be ...
Willk's user avatar
  • 2,964
1 vote

Does 1kg of lettuce have more energy than 1kg of beef?

only about 10 percent of energy stored as biomass in a trophic level is passed from one level to the next. "biomass in a trophic level is passed from one level to the next" is a lot of ...
johannes's user avatar
  • 111
1 vote

Does 1kg of lettuce have more energy than 1kg of beef?

Just to complement @DKNguyen's excellent answer, think about this: if you were raising cows on lettuce, how many cows would you have and how much lettuce would you have? Obviously you could not have ...
Coral Bleaching's user avatar
1 vote

is there a limit to how much humans can taste?

Yes, there is a threshold of taste. According to this article The taste system encodes information about the quantity as well as the identity of stimuli. In general, the higher the stimulus ...
Ojasvi's user avatar
  • 846
1 vote

Why do protein solutions have to be alkalised in biuret test?

You mix those two chemicals to get a Cu(OH) 2 colloid, if you mixed them earlier it would settle down and not form a colorful complex (as efficiently). Base is added first because (i presume) it ...
Francis L.'s user avatar
1 vote

How are Mono and Diglycerides metabolized without the Free Fatty Acids of Triglycerides?

Inside the intestinal lumen, di- and triacylglycerol are hydrolysed to free fatty acid and monoglyceride by lipase. These diffuse through the plasma membrane of enterocyte where they will used to ...
Eliane B.'s user avatar
  • 1,145
1 vote

Air bubble in addled egg

Egg shells look as if they're solid, but in fact they're filled with tiny pores through which air can and does diffuse. ...up to the time when internal pipping takes place, when pulmonary ...
iayork's user avatar
  • 14.3k
1 vote

Osmosis vs protein-binding in preserving foods through salting

In addition to killing microorganisms, the salt may provide a better environment for some 'beneficial' organisms, and a less beneficial environment for other 'problem' organisms. For instance, in ...
Jay Moore's user avatar
  • 827

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