The set of chemical reactions that happen in the cells of living organisms to sustain life.
16
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1answer
348 views
ATP cost for gene expression
How would you estimate the number of ATPs required to transcribe, export and translate a single eukariotic protein?
14
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2answers
913 views
Why is glucose our primary source of energy?
Is there any evolutionary reason for glucose being the "main" molecule used as a source of energy, beginning with glycolysis and subsequently cellular respiration (after being converted to two ...
12
votes
2answers
103 views
Relationship between our microbiome and personalized nutrition
Recently, it has been asked whether there are 'metabolic types' between humans that can benefit from a sort of personalized nutrition. One answer suggested that one discerning factor could be the ...
11
votes
3answers
564 views
How does the human body metabolize gasoline?
A Chinese man has been drinking gasoline to relieve his pain for 25 years. How does the human body metabolize gasoline? Also, what are the side-affects to gasoline?
11
votes
3answers
413 views
What happens to dextrorotatory amino acids in humans?
As indicated by this question, most of the amino acids in the human body have the L-chirality. As enzymes also have handedness, what happens to the D-amino acids that end up within the human body? Are ...
10
votes
2answers
6k views
What is a coupled reaction and why do cells couple reactions?
I was wondering what exactly a coupled reaction is and why cells couple them. I read the wikipedia article as well as several others, such as life.illinois.edu but I still don't get it. Could ...
9
votes
1answer
83 views
E. coli values for [enzymes], [metabolites] and kinetic rates
In my attempt to create a metabolic model of E. coli, I have found a comprehensive list of metabolic reactions and their stoichiometry. The one I am currently using is E. coli model iJO1366 (more ...
8
votes
3answers
2k views
Why can't the brain and red blood cells use fuels other than glucose?
The question is rather straight forward: I have always been curious as to why, but cannot find an explanation online.
I can imagine that the mechanism is different for each, but why does brain tissue ...
8
votes
1answer
130 views
What are the biochemical processes occurring when food spoils?
Let's assume for a minute that microbes themselves and their direct toxic products (i.e. endotoxins) aren't toxic to humans. Let's also discount any innate immune responses the body mounts against the ...
8
votes
1answer
115 views
What are the effects of caffeine on the mammalian circulatory system?
A friend of mine told me an anecdote about his mother, who drank too much caffeine, to the point she became hypotensive and would pass out. Because caffeine acts as a stimulant, I'm assuming the ...
8
votes
1answer
184 views
How long does it take for E. coli to shift feedstocks?
With our fermentations we're noticing that it takes an appreciable amount of time for E. coli (K12 variant) to change from being metabolically streamlined on amino acids to being metabolically ...
7
votes
1answer
1k views
Primary function of the enzyme lipoprotein lipase
I read here and here that the function of lipoprotein lipase is to facilitate fat uptake and storage in adipose tissue. Could anyone provide a slightly more expanded explanation, without going into ...
7
votes
1answer
54 views
Is there such thing as “meters per calorie” for living organisms?
I'm interested in learning if there's some way of quantifying the organism's metabolic efficiency associated with movement.
It seems to me that some organisms would be more efficient than others at ...
7
votes
1answer
90 views
What preceded ATP synthase?
ATP Synthase is ubiquitous throughout life on earth and so most probably evolved within the last universal common ancestor (LUCA) before that lineage diversified into the various kingdoms of life.
...
7
votes
2answers
158 views
Can a living organism run on electricity?
Each time I'm too lazy too cook I think it'd be cool to be able to just plug myselt into an outlet. Yet I know it is not possible - I need amino acids and a lot of other stuff that electricity can't ...
7
votes
2answers
116 views
During famine, does the human body do anything to prioritize which organs receive nutrients?
When food is scarce, the body slows its metabolism. Are there any other systems or processes that encourage prioritization of organs?
7
votes
1answer
80 views
obesity risk and single gene polymorphisms
I read a fairly recent meta-analysis of studies into the association between adult obesity and polymorphisms of the FTO gene (Peng et al., 2011). The paper looked at 59 studies and found that "FTO may ...
7
votes
1answer
95 views
How Antioxidants affects Human Metabolism?
I'd like to know how antioxidants affects the human metabolism and which ones are essential for metabolism processes.
7
votes
1answer
862 views
Effects of beer on muscle recovery after exercise
I noticed it several times that when I drink beer (even one bottle) after some heavy workout, the next day my muscles are more stiff than other times, and not the same way... Is it because that ...
6
votes
2answers
193 views
Is there such thing as a generic “metabolic type”?
A while ago I picked up a book called "Eat right for your metabolic type". The book discussed the effects of the endocrine system on the overall shape and the speed of metabolism.
The book outlined ...
6
votes
1answer
78 views
Mechanics of going from DNA sequence to metabolic network
My apologies for possibly a naive question. I'm a statistics type and have been asked to assist with analysis of metabolic pathways (and networks). However, I would like to have at least a layman's ...
6
votes
1answer
63 views
Cooking with sawdust
In a book about post-war Japan (Embracing Defeat, Dower) the author mentions a process for making sawdust at least partially edible, so it could be used in recipes in a 1:4 ratio with flour for ...
6
votes
2answers
43 views
Predicting and identifying microbes and enzymes DNA sequence with metabolic prediction
Presently I am working on metagenomics of coal biomethenation by bacterial consortium.
I have got the sequence result (Illumina). The sequence is huge and I can't predict anything from the sequence.
...
6
votes
1answer
307 views
How Does Green Tea Increase Metabolism?
According to the article "Green Tea Supplementation Affects Body Weight, Lipids, and Lipid Peroxidation in Obese Subjects with Metabolic Syndrome", Green tea increases metabolism and fat loss:
...
6
votes
2answers
105 views
In humans what is the last metabolic process to cease after death?
After death which of our body's metabolic processes will continue functioning for the longest?
5
votes
1answer
88 views
Why does muscle tissue have relatively constant AMP + ADP + AMP?
I was going over slides of energy expenditure in muscle cells. It mentions that in muscle tissue, the cell's energy charge ([ATP] / [AMP]) is the principle factor controlling glycolytic activity, and ...
5
votes
1answer
65 views
In which way would the yeast cell cope with the excess amount of methionine in the growth media?
I guess that when there is surplus of methionine in the cell it is incorporated in the TCA cycle as a succinyl CoA, with cysteine as a by-product. But now the cell has the surplus of cysteine. What ...
5
votes
1answer
56 views
What effect do oligosaccharides, like those found in legumes, have on the composition of intestinal flora in humans and if so how so?
I know that intestinal flora metabolising oligosaccharides, like those found in legumes, is the cause for the well known fact that legumes cause flatulence, but does an oligosaccharide-rich intestine ...
5
votes
1answer
48 views
What mechanisms tell temperate trees when to drop leaves?
I've been looking around and cannot find a definite answer on what it is that tells trees to change their metabolism and drop leaves. I see that such activity is called Deciduous.
What interests me ...
4
votes
2answers
155 views
Energy use by muscles, actual work done by muscles and more
Lately, I've started exercising in the gym and outside. I've also started to look at the details of food I eat.
Food usually has a label saying the amount of energy is inside it. For example, some ...
4
votes
1answer
94 views
Do effects of caffeine on human body change with habitual use?
I've been reading about homeostatic nature of a lot of neurobiological processes - the brain is trying to maintain a balance by desensitizing receptors, re-uptaking and breaking down ...
4
votes
2answers
80 views
Does the brain and the body use the same energy source (glucose/ATP)?
I've heard that the brain consumes quite a lot of oxygen and energy, compared to the rest of the body. What I'm interested in is if this is the kind of energy and oxygen that the rest of the body ...
4
votes
1answer
186 views
When is the lactase in lactose-free milk active?
Recently we have started suspecting that one of our children has hypolactasia (lactose intolerance), and so accordingly I have had my first exposure to lactose-free dairy- and dairy-like products. In ...
4
votes
1answer
235 views
Is there a relationship between efficiency of cellular metabolism and warm-blooded-ness?
My BIO 101 book states that when human cells convert glucose to ATP, the process is only approx 35% efficient, and much of the potential energy is lost as heat. However, that heat is useful to us in ...
4
votes
1answer
99 views
What is the biological mechanism underlying caffeine intolerance? (CYP1A2 or other?)
As far as I can tell, caffeine metabolism occurs primarily via the CYP1A2 enzyme. I am curious as to whether mutations in the CYP1A2 gene are associated with caffeine intolerance. Some site that is ...
4
votes
1answer
248 views
What does vitamin B6 and B12 absorption depend upon?
I'm looking at my question about homocysteine metabolism and am doing a followup inquiry into vitamins B6(Pyroxidine) and B12(Cyanocobalamin). I've found this interesting bit about vitamin B12 and am ...
4
votes
1answer
72 views
What biological systems are affected by Vitamin B6 (or B vitamins in general)?
B vitamins and particularly the B6 vitamin appears to the one of the main ingredients in energy drinks.
There has been anecdotal evidence from people interested in dreaming that ingestion of vitamin ...
4
votes
1answer
113 views
Are there any intersections between the biochemical pathways of uracil biosynthesis (or metabolism) and methionine degradation in eukaryotes?
Is there any way in which uracil biosynthesis or metabolism could help cell in degradation of toxic levels of methionine?
3
votes
1answer
88 views
What is the molecular basis of hangovers?
Well, most of us have experienced the wonderful feeling of the dreaded hangover. How does it work exactly? I imagine it has something to do with dehydration but what are the underlying mechanisms?
...
3
votes
2answers
886 views
Is there an evolutionary reason for the 5 electron transport complexes in plants and animals?
The electron transport chains of both the light reactions of photosynthesis (in plants) and oxidative phosphorylation (in animals) both contain 5 complexes including ATP synthase, as shown below.
...
3
votes
1answer
739 views
Does mixing alcoholic drinks really make you more drunk?
There is plenty of anecdotal evidence ("beer after wine and you'll feel fine, wine after beer will make you feel queer") that mixing alcoholic drink types leads to a stronger effect, but I can't find ...
3
votes
1answer
53 views
Why our body does not produce polyunsaturated fatty acids?
Our body does not produce two polyunsaturated fatty acids (PUFA): linoleic acid and alfa-linolenic acid.
I am thinking reasons for it.
Saturated fatty acids have more energy than unsaturated.
...
3
votes
1answer
56 views
Where does all the food go?
Food goes in, excrements come out. This seems obvious.
But it seems like the mass of the excrements is less than the one of the food.
Most people I asked answered: "There's a difference because it's ...
2
votes
1answer
49 views
Where does an organism store reserves of amino acids?
Where does an organism store reserves of the amino acids it needs to build various proteins it needs -- in the liver ? in the blood ? in every cell ?
Thanks
2
votes
1answer
111 views
Negative feedback in the fructose metabolism in liver
What happens in liver when large amount of fructose is consumed?
I vaguely remember my biochemistry lecturer telling us that the enzymes that process fructose in the liver does not have negative ...
2
votes
1answer
76 views
Circulation through the liver in light of drug metabolism
I have a lingering question which stems from an answer that I gave to What hydrolyses aspirin within the digestive tract and blood stream?
When a drug or any other substance is absorbed into the ...
2
votes
1answer
28 views
How is transport of glucose into prokaryotic cells different from transport into eukaryotic cells?
I was reading page 92 of Fundamentals of Microbiology, 4th edition, which states
In facilitated diffusion, the substance (glucose, for example) to be transported combines with a plasma membrane ...
2
votes
1answer
36 views
Are (baseline) high blood levels of melatonin associated with either circadian rhythm or mood disorders?
(Exogenous) melatonin is administered at night for treatment of circadian rhythm disorders, but melatonin taken during the day is linked with depression.
I would like to know if high blood levels of ...
2
votes
1answer
31 views
Is anaerobic activity during ketosis possible?
When a person's glucose and glycogen stores are depleted, which can occur due to fasting or due to a diet consisting largely of fat (like eskimo diets), the body produces its energy by breaking down ...
2
votes
1answer
92 views
How was the diversity between ethanol fermentation and lactic acid fermentation evolved?
Quite simply, some organisms metabolize glucose under anaerobic conditions via Glucose->(2) Pyruvic Acid->(2)Ethyl Alcohol. Some organisms, however, metabolize to lactic acid.
When did such a process ...
