16

This controlled experiment of burger decomposition explains in detail why fast food burgers do not decompose easily. The same can be applied to fries, which are smaller and come dehydrated from the frying. The main take-aways from this experiment are: 1: Dehydration is the main reason why fast food fries/burgers do not decompose easily. Placing the burgers ...


12

In humans (and all mammals), red blood cells lack mitochondria and therefore has no functional TCA cycle. They metabolize glucose mainly via glycolysis, forming lactate which is released from the cells; this yields 2 ATP for each glucose molecule, much less than complete oxidation (ca 30 ATP), but enough to support the red blood cells' energy needs. There ...


10

ATP is a bad medium for storing energy as detailed here. ATP has a molecular weight of 507 Da Glucose has a molecular weight of 180 Da, and contains the same amount of energy as 31 ATP molecules


10

From a theoretical perspective this is a very interesting question, mostly because it is difficult to completely abstain from carbohydrate intake on a normal diet. Even the popular low carb diets of the late 1990s and early 2000s (e.g. Atkins Diet, South Beach Diet) were just that, they were Low Carb, Not No Carb. We know there are essential dietary ...


9

This seems one form of a common question about evolution. That being: "Trait X would seem to be an advantage, so why can't organisms adapt to X? That is, why don't we have all traits that are advantageous at all? Why not just digest cellulose, but maybe why not lignin as well? Why shouldn't we photosynthesize our own food? What about sonar as well ...


9

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 oxidation. But without oxygen there is no other way to keep the glycolysis active for at least some energy supply. The difference is located in the enzymes available ...


6

well glycogen can be broken down into sugars a lot faster, many more branches means many more ends to clip individual sugars off of, that's how you mobilize the sugar for use, it is clipped of the end of a strand. With many more branches glycogen can mobilize more sugar more quickly. This is not important in plants but in animals that need to be able ...


6

The two structures on the left are correct; the one on the upper left is the alpha-D-fructofuranose form, while the one on the lower left is the beta-D-fructofuranose form. Fructose is a ketohexose (a six-carbon sugar with its carbonyl group present as a ketone group in the molecule's open-chain form); the carbonyl carbon (the 2-carbon, to be precise) is ...


5

The Atkins diet is based on that. Without carb intake, however, the citric acid cycle (CAC) eventually basically stops and proteins will be utilized to be converted to carb intermediates to feed the CAC. Progressive and strict use of the Atkins diet will eventually kill you as the CAC is essential to life. The idea behind Atkins is that fats will be used ...


5

In the process of exocytosis materials which are about to be released are transported in small vesicles to the plasma membrane. The plasma membrane fuses with these vesicles and this sets the substances free on the outside of the cell. See the figure (from here): The other possibility for transport vesicles is that they arrive at their target cell and ...


4

The question forgets that organisms consume materials for two reasons: To capture chemical energy (which it focuses on) and to gain molecules that the organism cannot otherwise produce. Cellulose effectively serves only one purpose in organisms that digest it: energy production. Eventually, it is broken down into H2O and CO2, both of which are excreted. ...


4

Even teachers are sometimes wrong. ;) Chitin is a homopolysaccharide. This just means that it is made up of repeating units of the same monosaccharide - in this case that monosaccharide is N-acetylglucosamine. Other examples of homopolysaccharides are glycogen and cellulose. The basic structure of chitin is shown below as a polymer of two N-...


4

While hemoglobin makes up about 90% of the protein in an RBC, there are many other proteins present as well, including enzymes in the anaerobic pentose phosphate pathway, which is responsible for metabolizing about 90% of the glucose entering the cell (the aerobic pathway takes care of the other 10%). There are also proteins responsible for maintaining the ...


4

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 optima in the acidic pH range. On the other hand, the salivary amylase that breaks down starch seems to be inactivated by the acidic environment. Sources: https:...


4

Summary The key difference between glycogen and amylopectin (the main constituent of starch) is not the number of α l,6-glycosidic branches, but their arrangement. In glycogen branches are successively subdivided, producing a relatively small globular structure that is unable to grow further. It is soluble in an aqueous environment and, with its numerous ...


4

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 acid is produced from pyruvate (end product of glycolysis). See Wikipedia:lactic acid fermentation.


4

The differential uptake of different isotopes of carbon is covered well at: https://en.m.wikipedia.org/wiki/Fractionation_of_carbon_isotopes_in_oxygenic_photosynthesis Plants have a lower proportion of C-13 than atmospheric CO2. The two mechanisms that cause this are the reduced diffusion speed of the heavier C-13, and an energetic difference in the chemical ...


4

Summary The mechanistic reason why fructose is converted to fructose 1-phosphate by fructokinase rather than fructose 6-phosphate by hexokinase is explained in terms of the Km values of fructose and glucose for the latter enzyme. A possible general rationale for the two distinct pathways of metabolism is to allow them to operate and be regulated ...


3

You asked three questions here, so I'll answer them one by one. Yes, you can survive with glycogen as the only source of carbohydrates, assuming that you also take other nutrients like proteins, fats, vitamins, etc. also because carbohydrates cannot supplement all of them. See this article: There are three macronutrients: carbohydrates, protein and fats. ...


3

Apology This question has a very simple answer which was provided in a comment by @EliKorvigo (and acknowledged by the poster) two years before writing this answer. However the commenter did not post an answer so the poster, instead of withdrawing his question accepted an answer that, although not factually incorrect, is not a full answer to the question. I ...


3

You need to make a distinction between polymers and monomers (or dimers). Typically, sugars are monomers like glucose, maltose, or fructose. Sucrose (table sugar) is a dimer. These are all carbohydrates (made up of carbon, oxygen, and hydrogen). Polymers of these sugars are also carbohydrates. For example, starch, glycogen, and cellulose. Cellulose, which ...


3

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 families with GLUT1 deficiency, where a diet with minimal amounts of glucose and carbohydrates digestible to glucose is required, aquafaba can represent an ...


3

The answer is relatively simple: Amylopectin is watersoluble, and this seems to be a classical textbook error, which has been propagated now for decades. As you say yourself, the only difference is the number of 1,6-glycosidic branches, which occur every 8-12 glucose monomers in glycogen and every 15-30 monomers in amylopectin. There are even scientific ...


3

The cause of the swelling is lack of lymphatic carriage capability of proteins to the muscles, because of systemic conditions affecting the circulation of proteins through your lymphatic system. There will be edema extracellularly because of insufficient carriage of proteins through lymphatic system. My schematic drawing about the fluid movement between ...


3

Oxygen in photosynthesis does not come from carbon dioxide. It comes from water and this is the step that actually requires light: Photolysis of water. The proton produced in this process is used to synthesize ATP and NADPH by a chemiosmotic process similar to what happens in mitochondria. These biochemical pathways are also referred to as Light reactions. ...


3

Too long for a comment. Just extending the answer from @prooffreader slightly. It's true that long carbon chains are present in lipids, but in proteins and nucleic acids there are chains of carbon atoms interspersed with other atoms: nucleic acids: -C[3']-O-P-O-C[5']-C-C[3']- protein: -C[alpha]-C-N-C(alpha)- So the ability of C to form stable bonds ...


3

We are carbon-based because carbon is the only molecule that is able to form the long, long chains of hundreds of molecules that are required to from proteins, DNA, etc. Absolutely no other molecule will do it. (Whatever you may have heard on Star Trek about Silicon-based life, Silicon doesn't form chains anywhere near as long.) Plus it's very handy in that ...


3

Firstly you must realize that all the above mentioned nuts are actually the seeds of plants. So the question now is which carbohydrate is mainly found in seeds of plants. During the double fertilization of angiosperms, one sperm fertilizes the egg to form the embryo while the other fertilizes the endosperm nucleus to form the endosperm which acts as the ...


3

No there is something else missing besides bacteria humans often already have the right bacteria but they don't digest most of the cellulose they ingest because digesting cellulose with bacteria is SLOW. Too slow to keep up with normal mammalian digestion. You need a specialized gut that either has a large complex stomach to keep recycling the cellulose in ...


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