Questions tagged [biochemistry]

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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6
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69 views

What is the fastest way to crystallise lysozyme (for student course)?

High school sudents are going to visit my university and I plan to demonstrate crystallisation of lysozyme. I ordered pure lysozyme from VWR. I can easily crystallise this within 15 min in batch (4% w/...
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44 views

What phosphorylates tau protein & and what causes tau to be phosphorylated?

I want to know what phosphorylates tau protein and its 6 isoforms. I know kinases cause phosphorylation events, and in tau it can be phosphorylated in a healthy neuron in the trans conformation, but ...
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1answer
45 views

Why do beta-1 and beta-2 adrenergic receptors result in two completely different effects (though both use Gs pathway)?

$\beta_2$ adrenergic Receptors are $G_s$-coupled 7-TM proteins. Considering that $G_s$ , by activation increases $[\text{cAMP}]_\text{cytosol}$ which inhibits MLCK of smooth muscles (and causes ...
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The truth behind human urine and marking territory?

So some years ago, I remember watching a survival show in which the host said that human males produce a type of chemical in the urine that animals such as wolves can acknowledge as a territory marker....
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122 views

Where do the protons in the mitochondrial intermembrane space originally come from?

I'm currently reviewing this concept in cellular respiration. The book which I'm using is Reece, Minorsky, Campbell's Biology and while it does a good job at explaining the process involved in the ...
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32 views

Can an epileptic seizure start in the spinal cord?

My understanding of an epileptic seizure is caused by "invalid electrical signaling" in the brain. Can these start from the spinal cord (outside the brain) and move into the brain and cause an ...
4
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51 views

Does Doxylamine have any Influence on the Monoaminergic System?

Does doxylamine have any affects on the monoaminergic system? Specifically I am interested in adrenergic or serotonergic activity but additional information on its dopaminergic activity won't hurt ...
4
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364 views

Virucides - Herbal and otherwise, for HHV6 type virus or any inner-cell virus

Does anyone know where I can find a reliable list of virucides (not anti-virus) that can be used by humans? This virucide must be able to affect viruses that are already inside the cells. St John's ...
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68 views

Cracking sounds made by glowing plankton

Recently I had opportunity to swim in place with glowing plankton, it was amazing experience and it as well gave birth to few questions in my head. I manged to google that they can glow thanks to ...
3
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1answer
84 views

Design rules for DNA linkers

I want to use double stranded DNA linkers to physically bind two "things" together, by grafting ssDNA on each one of them and using DNA hybridization as the locking mechanism. I do not expect the ...
3
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64 views

Light/Heavy Isotopes in Living Organisms

I was wondering, why are lighter isotopes (e.g. carbon-12 as opposed to carbon-13) preferentially used by life on Earth? Is their increased stability the only factor? Thanks in advance!
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How do molecular biologists determine biochemical pathways?

I'm new to this community, so hopefully this is the right place to ask this question. I know my question is really general, but in all of my biology courses we are merely taught the chemical pathways ...
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Can low melatonin levels and/or LED lights cause or exacerbate macular degeneration?

I have two questions that may or may not be interconnected. My first question is: Does melatonin prevent macular degeneration? Could low melatonin levels (caused by blue-rich light exposure in the ...
3
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53 views

Antibody staining

I am staining tissue sections and I did a mistake, I was supposed to have mixed 3 primary antibodies but I stained only with one of them. After the 1h incubation I washed 10 min with PBS and then I ...
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70 views

Effect of the Marcus Theory on Photosynthesis

As far as I know, the Marcus Theory explains the rates of electron transfers in reactions as a function of differences in free energy between the product/reactant's potential well. Furthermore, there ...
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60 views

Why can polar molecules like water pass aquaporin better than unpolar like H2 or CO2

We learned in our lecutre, that aquaporin lets Water pass, but blocks Ions like H+ and unpolar molecules like CO2 and H2. The reasons for the Ion blocking are comprehensible, but I dont get, why less-...
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60 views

Preparation of dihydroxyacetone phosphate from glycerine by fermentation

I read on Wikipedia that dihydroxyacetone (DHA) can be obtained from fermentation of glycerin. I would like to obtain dihydydroxyacetone phosphate (DHAP) for a science experiment but, since I'm 15, I ...
3
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72 views

Regulation of the concentration of precursors of DNA and RNA synthesis

What is the specific cellular process for regulating the amount of the four DNA bases (adenine, thymine, cytosine, and guanine) that are present in the cytoplasm of a cell? Basically, how do the cell'...
3
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60 views

Could trees be engineered to produce rainfall-nucleators?

Scientists are using genetic engineering to make trees produce more terpenes. Is it possible to genetically engineer trees to produce more hygroscopic volatile organic compounds? These trees could be ...
3
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245 views

Why does a broad-leaved evergreen (Mahonia aquifolium) has red leaves?

To my knowledge, oregon grape (Mahonia aquifolium) is purportedly an evergreen shrub? Deciduous broadleaf plants lose their leaves in autumn usually and before that as the leaves die they oxidize and ...
3
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47 views

Where do class 2 preservatives end up after digestion?

Do anybody know what happens to class 2 preservatives in general after they are digested - i.e details like weather they are absorbed into blood as simplest elements or excreted out or assimilated to ...
3
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Does alpha-amylase from different species have different *optimal* conditions?

Do the optimal conditions for the enzyme isoforms differ between species? Specifically, do the optimal pH and temperature for alpha-amylase differ for that enzyme produced by B. lichiniformis and A. ...
3
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202 views

What is the function of CETP?

I read up that CETP transfers cholesterol from HDL, which collected it from tissues, to VLDL. This VLDL is then sent back to the tissues, ultimately forming LDL internalised by cells. What is the ...
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64 views

What is the rationale behind reverse cholesterol transport?

Reverse cholesterol transport is transport of cholesterol from the tissues back to liver/VLDL. My question is why do the tissues have this extra cholesterol in the first place? Why would you ...
3
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77 views

What Chemical Trigger Causes Ectomycorrhiza To Change From Asexual To Sexual?

I want to know the trigger behind the change of asexual to sexual ectomycorrhiza when symbiosis with a tree root is formed. As ectomycorrhiza attaches itself to a root, it forms a relationship wherein ...
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859 views

Can I leave BL21(DE3) cells in room temperature?

I am preparing competent cells, and I finished inoculating a single colony in SOB. It has been incubating at 37 degrees Celsius for almost 16 hours since, and it's getting very late where I live. I ...
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48 views

Does blood typing still provide a use for ancient tissue analysis?

Modern techniques. In recent years, DNA sequencing has become extremely cheap. This, compounded by the ability to PCR miniscule samples to viable samples for analysis, means that aDNA can be ...
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273 views

How does estrogen influence collagen synthesis?

Through what mechanisms does estrogen interact with collagen synthesis? Especially in the context of elevated estrogen levels and genesis of purpura simplex .
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34 views

Does glycerol in E.coli culture media somehow inhibit the lac-operon?

I have have been taught that one should induce protein expression with IPTG at an OD of about 1.0 - 2.0 when E.coli grows it TB media (terrific broth). As a reference point, one typically induces ...
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20 views

What are the carbohydrates that are found in white rice?

From this Wikipedia page on rice, it is mentioned that 100g of rice contains 80 g of carbohydrates, of which 0.12 g is "sugar" and 1.3 g is "fibre". I believe the "fibre" ...
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2answers
47 views

How would one track a mineral nutrient in a plant in order to prove that nutrient has been re mobilized?

Before abscission - senescence of a plant structural components that contain mineral nutrients (E.g. Magnesium, Potassium...) are re-mobilized from the senescent tissue and used in other plant tissue ...
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23 views

How it will taste if one puts two substances on tongue simultaneously?

If we put two substances having different taste on tongue simultaneously how it will taste? Does specific part of tongue is sensitive to specific taste?
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Does it make sense to express membrane transporters as concentration?

Let's assume a situation where a molecule, S, is transported out of the cell by membrane transporter T. For simplicity we do not consider any other synthesis or production processes. Furthermore, we ...
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Can muscles remake pyruvate from lactic acid, or does it have to go to the liver in the Cori cycle?

When the muscle is exercising, and only anaerobic respiration is done, pyruvate -> lactate to regenerate NAD+. Lactate is then transported out of the muscle and into the liver, to regenerate glucose, ...
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What relation do glycerol-3-P DH and acyl-CoA DH have with Complex II of the ETC?

I am sorry if this may be a purely definitional/nomenclature question. Complex II of the electron transport chain (ETC) would be succinate dehydrogenase, transporting electrons to ubiquinone (and ...
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40 views

What makes the cytoplasm a reducing environment?

It is known that the cytoplasm is a "reducing" environment, where disulfide bonds cannot form (will soon be reduced to 2 cysteines) [I'm not putting a link as this is a fact in many biology textbooks]....
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Does an FAD:FADH2 ratio exist in the cytoplasm? (similar to NAD+:NADH ratio?)

I have learned about a lot of enzymes/proteins which are covalently bound to FAD, and use this as an oxidising agent. In vivo, FAD is (almost) always protein bound (very low concentrations of free FMN/...
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25 views

Why does Porous-tube Nutrient Delivery System cultivation improve nutritional quality of Okinawa spinach (Gyruna bicolor)?

I wrote a review paper and it involves in growth system of a plant “Okinawa Spinach (Gynura bicolor)”. A research of (Wang, Fu, & Liu, 2015) reported that Porous-tube Nutrient Delivery System (...
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39 views

What happens when you cook tree spinach with aluminum?

The Internet is filled with warnings that you shouldn't cook tree spinach(Cnidoscolus aconitifolius) in aluminum, because it will react and create toxins that cause explosive diarrhea when consumed. ...
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52 views

Appropriate regeneration of StrepTrap HP columns for FPLC

My question is related to protein purification using a ÄKTA FPLC. We used StrepTrap HP Columns (1 ml column Volume (CV)) from GE Healthcare Life Sciences to purify a strep-tagged protein. In the first ...
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0answers
22 views

Is there a relationship between HDL-C and LDL-C?

For a gentle introduction to cholesterol and its functions, see a great answer on SE Biology Whenever I read about how to deal with cholesterol level, the rule is to keep a low LDL fraction, ad a ...
2
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0answers
29 views

Why might a cell have no respiratory reserve capacity?

I am trying to understand why a cell might have minimal respiratory reserve capacity in the presence of unlimited substrate supply. This essentially means that the oxygen consumption rate (OCR) of the ...
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0answers
61 views

Why does pyruvate from lactate and pyruvate from other sources follow different pathways in gluconeogenesis?

My teacher taught me in a lecture that PEP forms from Pyruvate by two ways, based on their sources, that is - 1. If the Pyruvate was from lactate (by lactate dehydrogenase action), it gets shuttled ...
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1k 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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199 views

Is starch a better coagulant than cellulose?

In an experiment, I used plantain peels (with a very high starch content and very little cellulose) and grapefruit peels (with a very high cellulose content and no starch) as coagulants (ensuring that ...
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67 views

Can we investigate the cell biology of extinct microorganisms?

I know that there are microfossils, but not if we can we know about the organelles, genetics or macromolecules of the cells that left them behind.
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54 views

Measurement equation of Tree-Step pathway model

I am not specialist in biology but I want to test a parameters estimation method (based on Kalman filter) on the Tree-Step pathway model, but I cannot find a document that gives the measurement ...
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0answers
59 views

Sucrose inhibit onion root mitosis? Why?

I am doing an experiment about onion root growing. I had put an onion in different solutions of $C_{11} H_{22} O_1$ in H2O —with the root touching the water—: 0,1M; 0,2M; 0,3M; 0,4M; 0,5M. The ...
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0answers
107 views

Would I expect salt precipitate on fibres of DNA in a NaCl water solution?

I just recently conducted an experiment in my biochemistry class where we had to add DNA to distilled water, isotonic saline and 2.5M NaCl. I noticed different physical aspects depending on the ...
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What is the concentration/molecules per cell of iodothyronine deiodinase in a cell?

I'm trying to parameterize an in silico model and need the approximate concentration (M), or molecules per cell, of iodothyronine deiodinase type II (D2) enzyme in a human cell, ideally a glial cell. ...

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