The study of chemistry within the scope of biology: the compounds that occur and the reactions involving them in living organisms.

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fibrinogens and fibrins - are they the same molecule?

Some proteins are "activated", like fibrinogens; they are turned into fibrins by thrombins, and then the fibrins can aid in blood clotting. Are fibrinogens and fibrins the same molecule, just in ...
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35 views

Cells created using differently aligned proteins

I remember reading that scientist were making cells (I assume bacteria), that used differently oriented proteins to create a whole new class of life. Because apparently right and left aligned proteins ...
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59 views

Missing 4$H_2O$s (per glucose) in Cellular Respiration… Where can they be?

I having trouble understanding the equation of the cellular respiration. The thing that bothers me is the number of $H_2O$ molecules. Generally, cellular respiration is written thus : $C_6H_{12}O_6 + ...
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55 views

In what forms do plants and animals excrete sulfur?

Sulfur is part of the amino acids cystein and methionin, plants take up sulfur in the form of $H_2S$. These organisms will also need a way to get rid of excess sulfur, how? In what compounds? Judging ...
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29 views

Correlating Ki values of pesticides to bacterial growth

Four pesticides P1 to P4 are reversible inhibitors of an enzyme E that is essential for the growth of a bacterium B. Their Ki values are given in the table below. Each of these four pesticides ...
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21 views

Source of energy of adipocytes

Since adipocytes export fatty acids and don't use them as an energy source, which is the main source of energy for this cells?
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228 views

Shine-Dalgarno sequence and expressing proteins

Shine-Dalgarno sequence present in the prokaryotic mRNA plays a role in initiation of translation. In eukaryotes a Shine-Dalgarno like sequence is present but does not play an important role in ...
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76 views

(Web)app to search metabolic/signalling pathways

I'm looking for an application where you can find pathways by selecting a chemical occurring in it. So, for example, selecting 6-phosphogluconolactone brings up the pentose phosphate pathway or any ...
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1answer
56 views

How does ultraviolet light influence the decay process of wood?

Given a piece of wood, how does putting it in the sun or not influence the rate of decay due to rot (assuming that it's in an otherwise humid environment)?
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742 views

Is Zymase, A Complex of Enzymes? Which ones?

Some websites state that the enzyme zymase (which I understand to be a complex of several enzymes) is responsible for catalyzing glycolysis in order to produce pyruvate. On the other hand, some ...
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106 views

Which is the correct statement on proteins?

I need help with one of the questions on my biochemistry assignment Choose the correct statement on proteins: a) proteins are folded by alpha-helix b) proteins can preserve their function even if ...
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109 views

How are the correct tRNAs transported to the ribosome?

I have been trying to understand how the tRNA transporting the correct amino acid required by the ribosome reaches the ribosome. The only way I can imagine this happening is that all types of ...
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134 views

Does animal fat and meat contributes differently to our body?

Is animal fat harmful to our body or is it harmful if the amount eaten exceeds a certain amount? I have heard fat is more concentrated than protein. If I am correct then we can get more energy from ...
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55 views

Isoprenoid Diphosphate Concentration in Yeast saccharomyces cerevisiae

Isoprenoid Diphosphate(IPP) is an important metabolites which is precursor in lot of secondary metabolites like Dolichol diphosphate, ubiquinone, prenylated proteins and carotenoid (not synthesized ...
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200 views

What is the use of futile reaction cycling such as Fruc-P to Fruc-BP?

One rate-limiting step of glycolysis is the conversion of Fructose-Phosphate (Fruc-P) to Fructose-Bisphosphate (Fruc-BP), catalysed by Phosphofructokinase (PFK). The reaction involves hydrolysing one ...
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1answer
36 views

Can the sulphur content of biological material be reliably calculated from fat, fibre and protein contents (Weender Analysis)?

An often-used analysis of feedstocks for lifestocks is the Weender analysis, which basically divides the volatile solid content into fats, fibre and protein, as well as N-free matter. I found no ...
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64 views

Can we use Acetyl Phosphate instead of Acetyl CoA in TCA?

I am thinking Citric Acid cycle and activation of the end parts of Acetyl and alfa-ketoglutarate. Let's consider only now Acetyl to make things simpler. I have tried to explain the thing by symmetry ...
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170 views

What is the biochemical reason for mental fatigue?

Is it known exactly why the brain needs sleep? What's dropping low / going high when we experience mental fatigue? I can see why low glucose could result in mental fatigue, are other reasons known?
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119 views

Is eating salt dangerous for the brain?

I read somewhere that eating a lot of salt will raise blood pressure, which will in turn damage brain tissue. This is because water molecules gather around salt ions, thus making it harder for the ...
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131 views

What are the biochemical interactions between human body and Polyethylene?

Our waterways and oceans are showing increased levels of plastic contamination. These plastics are breaking down into smaller pieces. When one goes to the beach and plays in the surf they often ...
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1answer
136 views

How to manufacture different sized micelles in nano -scale?

I am trying to answer q5: "How can you manufacture micelles in A) nanometerer -scale B) and in ten nanometer -scale?" My Thinking Observations and some thinking Oil in ...
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0answers
16 views

What ideas have been proposed about what the first cell would have been like? [closed]

Have any researchers proposed a potential first cell (what it looks like, how it functions), and what do/would they base it on? Ubiquity of life, available ingredients? Also, in the same way protein ...
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1answer
39 views

Why is deficiency of thiamin characterized by brain malfunction [closed]

Why is deficiency of thiamin characterized by brain malfunction.
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27 views

recombinant peptide MHC complex

What is recombinant peptide-MHC complex??? Recombinant DNA means "to bring together genetic material from multiple sources, creating sequences that would not otherwise be found in biological ...
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25 views

How does Temperature influences the rate of protein turnover? [duplicate]

Question How (quantitatively speaking) does temperature influences rate of turnover of transcription factors? Which protein? As I am not looking for any accurate number I am talking about an ...
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36 views

How to calculate when the velocity declines in an Enzyme Kinetics Problem [closed]

If you have an E,S pair that has KM and Vmax values of 2 mM and 1 mM/sec/μM enzyme and you start the reaction with 10 mM [S] and 1 μM [E], approximately how long will the E,S system stay in the ...
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41 views

Enzyme Assay - pectinase

During assaying an enzyme at high temperature, the substrate (Pectin) is degraded by the high temperature rather than by enzyme, so, how can I minimize degradation of the substrate by the temperature? ...
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29 views

Can non-carbonated energy drinks boost alcohol intoxication?

I just read news article about banning caffeine in alcohol drinks and about that energy drinks increase the urge to drink alcohol. Energy drinks cause sugar intoxication - answer about it here ...
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58 views

amino acid containing branched side chain [closed]

Branched-chain amino acid are degraded by branched chain alpha-keto acid dehydrogenase complex. These amino acids aren't degraded in liver because of the absence of this enzyme(in liver).Why the ...
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42 views

Vitamin D oral intake, transportation and absorption

Several factors affecting vitamin D and its active form absorption and storage acidity of stomach (not significant effect) cytopathic effects of viruses cytopathic effects of bacteria where the ...
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24 views

Is life in a supercritical fluid possible?

Someone claimed that the dinosaurs could only live because back then athmospheric density was around 650 kg/m³, providing some buyoncy, this claim is checked on Skeptics SE. The claim itself is beside ...
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37 views

Nearly Exhaustive List for Cholesterol Pathways

I have run across an interesting case that is similar to only two others I've encountered. What makes it interesting is the combination of undetectable (under normal testing conditions, can elaborate ...
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40 views

Ferredoxin synthesis pathways

I have been thinking about some alternative CO₂ fixation pathways. As almost all of them include ferredoxin reduction I started to wonder where does the ferredoxin comes from. I could not find any of ...
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64 views

Enzymes that can catalyze multiple reactions [closed]

If the lock and key model were true, only one enzyme would be able to catalyze a reaction. However, some enzymes can catalyze multiple reactions. What are some examples of enzymes that can catalyze ...
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75 views

Osmosis - occurring in both ways?

So I did a prac to identify the osmotic potential of potato tuber cells. There were 5 test tubes with different concentrations of sucrose (0M,0.25M,0.5M,0.75M,1M); a small slice of potato was placed ...
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58 views

What is the biochemical pathway of fluoride?

Fluoride is a common active ingredient in tooth paste to prevent dental caries. It is also added or removed from the water supply in some communities for the same reason, but in children only. My ...
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46 views

Why does the ovum prefers to be arrested at metaphase 2 of meosis before fertilization? What is the possible advantage of this process?

Why does the human ovum prefers to be arrested at metaphase 2 of meosis before fertilization? What is the possible advantage of this process??Please help me with it.
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57 views

What are the ingredients of Pheromone Trap using for controlling Fruit flies of cucumber?

Pheromone Traps are used for fruit fly control. But I have no idea which ingredients or chemicals are used for preparing Pheromone trap
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48 views

Is an antivenom venomous?

What happens when someone takes an anti-venom for an animal they weren't bit by, either for incorrect identification of the animal they were bit by or if they weren't bit at all? I am looking for the ...
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57 views

Why is a nicotinamide-tryptophan combination used to treat affective episodes in a few older clinical trials?

At least one of the journal articles that reported on such clinical trials allured to the nicotinamide-tryptophan pathway that I assume must be related to the metabolism of tryptophan into serotonin ...
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40 views

Protocol for immobilize oligo to solid [closed]

I'm learning about microarrays and understand that an oligonucleotide can be immobilized to a solid like a CD acrylic plastic by modifying the oligo. Does anyone have a good protocol for modifying a ...
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55 views

When a Lysosome's bonding sites all get bonded to, what is the most resource and energy efficient way to handle the used Lysosome?

Let's say a Lysosome that bonds to a hazardous material to neutralize it has all bonding sites used up. would it be more safe / efficient to excrete the entire Lysosome / hazardous material molecule ...
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91 views

Why does trans fat decrease hdl's? [closed]

I understand that cis fats increases hdl's, and unsaturated fat increases ldl's, but trans fat increases hdl's and it decreases ldl's. Why does trans fat do this?
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35 views

Glutamine analysis

I use to run a method to analyse all the amino-acids in a food sample. For that I have to hydrololyse the sample and in the last stage of the method I read the amino acids with a ion exchange ...
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0answers
56 views

Solid phase use in HIV rapid tests [closed]

I have a question in regards to my HIV test research. The rapid tests like Orasures Oraquick contains a strip of synthetic peptides that are used to represent proteins found in the envelope region of ...
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0answers
70 views

When should endocytosis inhibitors be used in cell binding assays? [closed]

I'm beginning to do some cell-binding assays and I would like for my proteins to not be endocytosed by my mammalian cells. Typical suggestions are for the cells to be kept on ice and that the binding ...
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2answers
96 views

alpha tubulin molecular weight problem

Is there any academic reference that shows α-tubulin is around 50-55 kDa? The only thing I found is some data sheets from companies. I need the real reference.
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2answers
127 views

Is Hydrogen gas present in biogas, and does it spontaneously ignite?

Is Hydrogen gas present in biogas? As it is highly inflammable, may it ignite the other gases like methane?
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1answer
23 views

Can the same protein be represented by primary,secondary,tertiary structure? [closed]

As my book says: Protein can be represented by 4 structures. The primary structure represents the main chain and positions of amino acid residues. But actually, protein is not a rod but rather a ...
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36 views

About molecules and their shape

When a molecule is being used in some biochemical process it has a certain 3-d structure. Is this maintained throughout it's usage or can one specific molecule change it's 3-d shape while it is being ...