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Metabolism is the set of defined biochemical transformations occuring within the cells of living organisms.

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What is (are) the medium of conduction for an electrical current with an external source in the human body?

I am trying to get some background for some personal research I am doing into the effects of Electro Convulsive Therapy. I don't understand how electric current from an external household source, say, ...
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19 views

How cells determine how many enzymes are needed for digestion

How do pancreatic cells, epithelial cells of the stomach and intestinal epithelium cells determine the right amount of enzymes for digesting carbohydrates, proteins, fats? How does the pancreas ...
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14 views

What is oxygen used for in cancer cells other than respiration?

This question stems from a reflection I had on cancer cells: It is known that cancer cells switching from aerobic respiration to anaerobic metabolism. Hence, they should be able to survive in the ...
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13 views

Why would BMR depend on the weight ?Also, how does the BMR correlate with the weight of the man?

The question described here is based on interpreting data from the graphs and relates the knowledge of BMR with weight of the man.
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11 views

Are there chemicals/materials which when injected in blood stream remains there for long?

Does human body detect all foreign bodies? If a chemical or pathogen or tiny particles(few microns diameter) are injected in blood stream, will they be removed from the body or destroyed sooner or ...
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2answers
74 views

Why is Cacao a stimulant?

As I write this I've just eaten a fair amount of cacao (not cocoa) powder and it's given me quite a buzz. I've googled the effects and the Internet seems to think it's somehow psychoactive although it'...
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87 views

How does a glucose molecule enter the cell from blood vessel?

The transporters in the plasma membrane of the cells promote the entry of glucose molecules from the extracellular matrix to the cytosol of the cell. Could someone explain how does the nutrient ...
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0answers
14 views

Why is some scat in the form of little pellets?

The scat I most often encounter when out and about is from coyotes, black bears, deers and rodents. The deer and rodent droppings I find are in little pellets, what is different about their digestive ...
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1answer
44 views

How does anaerobic bacteria produce ATP for it's own cellular activities?

Anaerobic bacteria utilise glycolysis: Glucose + 2 P + 2 NAD+ => 2 ATP + 2 H + 2 NADH + 2 H2O + 2 Pyruvate followed by fermentation: Pyruvate + NADH => Lactate + NAD+ The resultant NAD+ formed ...
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32 views

What determines the metabolic pathways that a biological cell is able to carry?

For example: human cells (eukaryotes) can utilize the Kreb's cycle pathway to generate more ATP after glycolysis, but most bacteria cannot utilise the Kreb's cycle plant cells can utilise the ...
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17 views

Retention period of fat soluble drug

Are fat-soluble drugs remain in the human body long after their usage? If they remain in the body, how it can be detected?
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51 views

Can the face bones be “compressed” or forced together? What would happen? [closed]

Say someone doesn't like that their maxilla bone is too long because the height of the maxilla affects the placement, position and angle of the mandible relatively. If one were to apply mechanical ...
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1answer
24 views

How would a medication cause a one to maintain a different weight?

This isn’t really a medical question, I’m just really curious about this. I was maintaining weight A and then started taking a medication that brought me to weight B. While on the medication, I ...
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24 views

What is the actual charge of NAD at physiological pH (roughly 7)?

I am curating a metabolic model using CobraPY. Mass imbalances often occur in equations. Many different websites e.g. Kegg, ModelSEED, PUBCHEM, etc. have differing charges and formulas for compounds. ...
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0answers
21 views

What waste products do cells secrete in culture, and at what rate?

I am designing microfluidic chips for mammalian cell culture. One aspect I am interested in modeling is the rate at which I must renew media to ensure that: Cells receive enough nutrients Cytotoxic ...
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0answers
26 views

What determines the energy efficiency of our bodies?

Ingested food is broken down into the macronutrient components and then absorbed into the body. They are then used immediately or stored for future use. However, our energy efficiency is very low. So, ...
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1answer
56 views

Can something like McDonalds be considered a life form?

"The current definition is that organisms are open systems that maintain homeostasis, are composed of cells, have a life cycle, undergo metabolism, can grow, adapt to their environment, respond to ...
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2answers
97 views

If life began at sea, why organisms are less salty than the sea?

We may take it for granted that a fish, a seaweed, or clams are not too salty to eat, although the sea around them is salty. I know about the existence of a mechanism which prevents their body from ...
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1answer
82 views

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

Having difficulty figuring out what the body does with ingested mono and diglycerides if the usual process of TAG metabolism includes the FFA released from the TAG returning to the MAG to recreate a ...
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1answer
134 views

Does Povidone-Iodine that penetrates through the skin stays in the body (cells, liver etc)?

Here it says on povidone-iodine: "Route of Elimination: Povidone-Iodine is intended for topical application and is not eliminated" "Clearance: Povidone-Iodine is intended for topical ...
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1answer
43 views

Specific Neurons that Require Glucose

I've been doing a bit of armchair biology lately, and have been interested in the metabolic flexibility of neurons. My understanding is that, besides glucose, many neurons can metabolize lactic acid ...
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1answer
102 views

Why is hydrogen sulphide being generated on Caribbean beaches?

Once again, there has been a massive influx of Sargassum weed in the Caribbean. It is coming ashore on Atlantic facing beaches and forming piles up to 3m deep. As it dries and decays, hydrogen ...
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10 views

Higher Dissolved Oxygen Content

I conducted a project where the metabolic rates of Hermit Crabs were to be measured in reaction to changing pH. I used SeaChem Acid Buffer to lower pH - it converts carbonate alkalinity (CO3 2-) to ...
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1answer
38 views

How is the urea cycle regulated with respect to protein deficit?

Proteins cannot be stored in the body. Excess proteins from the diet are deaminated in the urea cycle that takes place in the liver. The liver is the first contact since these amino acids are ...
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1answer
58 views

Can E. coli make pyruvate from acetate?

What pathway would E. coli use to make pyruvate from acetate? I have found several papers that refer to a possible mechanism that could move acetate to pyruvate via a three-step process: Step 1: ...
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0answers
23 views

In ketogenesis, why is acetacetyl-CoA not directly hydrolized to acetoacetate in ketogenesis?

Ketogenesis pathway maps show acetoacetyl-CoA converted to HMG-CoA and only then to the first ketone body acetoacetate. Why this detour instead of directly hydrolyzing off the CoA to get there in a ...
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1answer
72 views

When you lose weight, how does the mass exit your body?

As a thought experiment, consider the case of Angus Barbiery, who allegedly lost almost 200kg in about a year by not eating at all, save for necessary nutrients provided as supplements. My question ...
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0answers
98 views

Why does GLUT2 (With a high Km), bind less glucose at a lower glucose concentration (below Km)?

A text I am reading says "GLUT2 is a low-affinity transporter in hepatocytes and pancreatic cells. After a meal, blood travels through the hepatic portal vein and GLUT 2 captures excess glucose for ...
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30 views

Dangers of excess blood protein? [closed]

Like glucose, amino acids are also insulinogenic as well. So, presumably, just like glucose, the body would also like to keep amino acids levels in the blood stream below (or within) some certain ...
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1answer
23 views

Are some polyketides enzymes?

I am currently reading a "book" (rather an article) called "Protein Modelling & Molecular Docking: Modeller, Autodock". The abstract starts with the following sentence : Polyketides are a ...
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1answer
48 views

Cause of Obesity

Considering the normal function of adipose tissue in sequestering 'persistent organic pollutants [POPs]', is there any evidence that the existence of such POPs within fat cells interferes with the ...
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2answers
134 views

Was lactose present in the environment before the evolution of mammals?

Are there lactose sources other than dairy products in nature? I tried to search for it but I did not find anything. The question arose because I was wondering whether lactose-utilising enzymes in ...
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0answers
19 views

Bacteria utilize short chain fatty acid as energy source

I'm doing research about the short chain fatty acid producing bacteria. I studied 7 short chain fatty acid (acetic propionic butyric isobutyric valeric isovaleric and captionic). and I found that the ...
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0answers
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What happens to lipoprotein lipase after a sugar only diet?

Insulin increases the activity of lipoprotein lipase thay allows cells to take in lipids from chylomicrons in the blood. If a person takes a sugar only meal like drinking coke, insulin is released. ...
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1answer
83 views

Does thyroxine increase BMR or metabolic rate?

I know that thyroxine increases the metabolic rate, but my teacher said it increases the metabolic rate, not the basal metabolic rate, the basal metabolic rate is always the same. What's the ...
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1answer
245 views

ATP Hydrolysis to AMP in the Urea Cycle. What is the Free Energy Change?

How is the hydrolysis of ATP into AMP and PPi in making arginosuccinate equivalent to the hydrolysis of 2 ATP?
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2answers
80 views

Why are my calculations for O2 requirements of daily metabolism so far off?

When I attempt to calculate the O2 necessary for a day of metabolism at rest (for an imaginary average human) and compare it with the expected O2 consumed per day my results differ by a factor of 3. I ...
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1answer
108 views

Why can't humans use dietary citric or acetic acid as a primary source of energy?

As the Krebs cycle is involved with the conversion of food in to citric acid, why can't eating citric acid be used as a temporary primary source of energy - in place of fat/carbohydrate/protein?? It ...
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101 views

Transaldolase vs Transketolase

What is the difference between transaldolase and transketolase in the pentose phosphate pathway? From what i understand, they both catalyze the transfer of carbon chains from 1 aldose into 1 ketose to ...
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1answer
51 views

why is LPL (lipoprotein-lipase) down-regulated during fasting?

During fasting our body needs additional sources of energy and that's why triglycerides are broken down into fatty acids and glycerol. where fatty acids can be used to generate acetyl-coA and ...
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2answers
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Is lysergic acid diethylamide (LSD) metabolized in the body?

Is LSD broken down into other compounds by enzymes or hormones? If so, at what point and where in the body does this happen? I researched several papers appearing in a google search, but unfortunately ...
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1answer
60 views

Is there any evidence that supports glycolysis in mitochondria or chloroplasts?

Glycolysis is known to be a part of cellular metabolism undergone by both eukaryotic and prokaryotic cells, whether under aerobic or anaerobic conditions. As the endosymbiotic theory states that ...
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4 views

How short chain fatty acids directly enter blood vessels?

Long chain fatty acids enter lymph and then get drained into blood vessels. But why short chain fatty acids don't go this pathway? Is it related with solubility?
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2answers
215 views

Is there a point in our life when ALL the atoms from our childhood's body get replaced?

The evolutionary biologist and Oxford professor Richard Dawkins makes on his TED talk the rather interesting suggestion that we human beings, are in nature more similar to a wave than an object. In ...
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39 views

Simplest known form of aerobic glycolysis

What is the simplest known way that an organism performs aerobic glycolysis? In other words, what is the simplest known way known to convert glucose into $\ce{H2O}$ and $\ce{CO2}$, other than by ...
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19 views

Can I supplement breathing by eating a lot of sugar and converting it to lipids?

So obviously not but would it be easier to hold your breath after eating a lot of sugar? My reason is that carbohydrates have oxygen and the fats they get stored into don't, so that oxygen has to go ...
3
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1answer
58 views

Extra-mitochondrial conversion of Acyl Carnitine to Acyl CoA

Normally fatty acids in the form of acyl CoA are converted to acyl carnitine in a reaction catalysed by carnitine palmitoyltransferase I (CPT1), which is also known as carnitine acyltransferase I. ...
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1answer
42 views

Does minimizing hunger maximize weight gain?

Due to the "obesity epidemic," there is a lot of focus on the causes of weight gain. We typically talk about strategies to cause weight loss, but what about strategies to minimize/maximize hunger? ...
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69 views

Breeding mosquitoes at lower temperature

It is well known fact that, to slow down the growth of drosophila, they are grown at 18-19 degree Celsius. It helps in maintaining stocks for longer time without frequent change of food. Is it ...
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1answer
125 views

Negative Oxygen Consumption Rate

Oxygen consumption rate (OCR) is defined as the rate at which cells consume oxygen. I reason that for cells not capable of photosynthesis, OCR is strictly non-negative. That was until I read this ...