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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233 views

Plants without bacteria? is it theoretically possible?

I know from school, that all live on the Earth need bacteria as low-level "machines" that break down/extract/convert/produce chemical elements and combinations, other high-level organisms needed. But ...
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1answer
52 views

Which mammals cannot synthesize taurine?

It is fairly common knowledge that domesticated cats cannot synthesize the compound taurine. Other mammals seem to be able to synthesize taurine from cysteine [source]. Are there other mammals that ...
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44 views

In flowering plants food is transported in which form? [closed]

In flowering plants food is transported in which form? I searched on google and found that it is sucrose. Why not glucose/fructose/starch?
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27 views

Is water vapour a product of fossil fuel oxidation?

In textbooks, while water vapour and carbon dioxide are said to be the greenhouses gases which are most abundant in the atmosphere, when a table is given showing the top greenhouse gases emitted by ...
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77 views

Goodwin oscillator explained

Hello I have been reading papers about the Goodwin oscillator and I found that the equations are kind of tricky. Specially the part of the hill coefficient. In his paper "An entrainment model for ...
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1answer
23 views

What are in common between transcription factors?

In terms of their structures (primary to tertiary) and locations? Why do they have these commonalities? Or are any of these commonalities critical to their functions?
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41 views

amount of tRNA and its extra arm

How much of the total RNAs is tRNA? Some say 15% and some 20%. Those percentages came from my different teachers. Which is correct? And what are the functions of the extra arm (variable loop) of tRNA? ...
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76 views

Where is sialic group in gangliosides that form ABO blood groups?

A ganglioside is a molecule composed of a glycosphingolipid (ceramide and oligosaccharide) with one or more sialic acids (e.g. n-acetylneuraminic acid, NANA) linked on the sugar chain. (source: ...
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90 views

How the chaotropic agents help in purification of DNA molecule?

Those plants which are rich in secondary metabolites and polysaccharides DNA isolation can be done using certain chaotropic agents? can any one explain how it works?
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84 views

Getting PCR amplification at annealing higher than Tm!

I am amplifying a gene where in a gradient pcr i am getting amplification at an annealing temperature about 5 degrees (67) higher than Tm (62.5)? What is wrong here? Also, I am getting a very strong ...
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255 views

Polysaccharide vs Macromolecule

I'm having trouble understanding the difference between Polysaccharide and Macromolecule. I know that polysaccharides are made of chains of monosaccharides. In addition, I know that ...
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1answer
134 views

Bradford Reagent Disposal

I am a graduate student volunteering in a professor's lab being tasked with finding out how to dispose of certain hazardous materials. I have encountered a problem with disposing of Bradford's ...
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1answer
205 views

Why does SDS-PAGE use for protein, and agarose use for nucleic acid?

My question maybe very primary, but after I learned this part, questions always follow me. SDS-PAGE gel works for detect protein, agarose gel works for detect nucleic acid, so here is my question: 1. ...
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44 views

Is galvinoxyl antioxidant assay possible using NMR spectroscopy?

I would like to perform an antioxidant assay using the galvinoxyl protocol. The protocol states that we need EPR spectroscopy, but only NMR spectroscopy is available at my institution. Is there an ...
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1answer
31 views

How is Glycophorin A and straphylococcal related to Escherichia coli and what does readily purified mean in this context?

I am reviewing the paper "Glycophorin A Dimerization Is Driven by Specific Interactions between Transmembrane Alpha-Helices." There is a statement in the abstract which I don't understand: "The ...
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1answer
50 views

What are the factors on which protein-protein interaction depend? [closed]

Does protein-protein interaction only happens when one of them is basic and the other acidic? Do protein interactions also depend on the protein structure? Are there more factors?
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1answer
3k views

How is ATP involved in muscle contraction?

The sliding filament mechanism as explained by my text does not elaborate on how ATP is involved in the cross bridge binding and contraction process. How does muscle contraction utilize ATP? In my ...
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1answer
50 views

ratio between heat transfer coefficient and thermal conductivity [closed]

Consider the Robin boundary condition for the diffusion/heat equation $\mathrm{u_t=a(t)u_{xx}+f(x,t)}$: $$\mathrm{-k(t)u_x(0,t)=h(t)u(0,t)}$$ or $$\mathrm{u_x(0,t)+\frac{h(t)}{k(t)}u(0,t)=0}$$ ...
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1answer
291 views

Pasteurization and Bioavailability of Antioxidants in Beet Juice

What are the effects of pasteurization on the antioxidants found in beet juice ? Does the process render most of the beneficial nutrients (betaine) useless and make them unable for the body to process ...
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3answers
201 views

Does the necessary Carbon Dioxide need to be in the atmosphere for mammals?

In the answers to this question, we've learnt that carbon dioxide is necessary for mammalian life, but is it necessary in the atmosphere/to breathe it in? Or does the act of respiration give a ...
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2answers
45 views

Determination of a chemical compound in a non-homogeneous sample

This is a more generalized question of my other question here. I want to know if it is possible to determine a chemical compound in a non-homogeneous sample. I am asking this because we are aiming ...
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1answer
50 views

Is there a biological environment that we can we assume glutamate exists as glutamic acid?

In the body we almost always assume that glutamate exists as glutamate rather than glutamic acid. It is so commonly glutamate yet glutamic acid and glutamate share the abbreviations of Glu and E. From ...
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1answer
47 views

Dehydration from caffeine, alcohol and other

Tea, Coffee, Beer, Coke etc… I wonder if the benefit from amount of fluid we get from them is bigger or smaller then the handicap of dehydration. In other words it is worth to drink them if we want ...
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1answer
62 views

How is oxygen and carbon dioxide exchange mediated by hemoglobin? [closed]

Oxygen is transferred by hemoglobin from the lungs to tissues, while carbon dioxide is transferred by hemoglobin from tissues to lungs. How is this regulated bidirectional transfer mediated?
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1answer
37 views

What enables azacitidine to incorporate into both DNA and RNA?

I did a mini-project on the drug azacitidine for my pharmacology class, and I learned that azacitidine has the ability to incorporate into both DNA and RNA. I think this is really unique because a ...
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1answer
137 views

How is the rate of transcription influenced by temperature?

How is the rate of transcription influenced by temperature? More precisely, I am looking for an article who quantitatively measured the rate of transcription of an "average gene" and show how this ...
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1answer
102 views

Influence of temperature on protein binding and decay rates

For computer modeling purposes, I am looking for some referenced quantitative measurements of the effect(s) of temperature on the dynamic of biochemical reactions. Question In particular, my ...
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1answer
239 views

What is the expected effect of pH on the activity of a fungal pectinase?

I am working on an enzyme assay for a fungal pectinase.I assayed the enzyme in different buffers from pH 1-12.5 However,the enzyme has good activities starting from pH1-10.5. Is it possible to have ...
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1answer
72 views

What is an effective method for putting on blue rubber butyl stoppers?

They look like this. We have to do a lot of gas sampling and these are really difficult to assemble. I've been scouring the internet for advice but there are none. Do you have experience with ...
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2answers
301 views

Significance of synthesis of D-glucose in plants..?

why plants can only synthesize D-glucose why not L-glucose along with D glucose. I know it very well that plants have only enzymes which can synthesize D-glucose but Why not they have enzymes which ...
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1answer
26 views

Primers on Dystonia

Where can I get a good biochemical overview of dystonia? I will be working in a research lab that focuses on dystonia and I would like to not be clueless.
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268 views

How do a particular arrangement of atoms become self aware? [closed]

At the simplest level, we're all just atoms, animals, plants and humans alike. But what I don't understand, is how a particular arrangement of atoms such as us can become self aware, and be able to ...
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1answer
537 views

What is reductive deamination?

This presentation on anaerobic digestion mentions (pg. 19) two major pathways for the digestion of amino acids: Stickland reaction and reductive deamination. While I find some info on the former, what ...
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1answer
66 views

Concentration of DNA by isopropanol

I have read that DNA can be concentrated by addition of isopropanol. What does "concentrated" mean? What does isopropanol do on a molecular level to concentrate DNA?
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117 views

Why only water in liquid form is essential to live?

My question is:- Only liquid water supports almost every living organism's metabolism, neither the vapour nor the condensed form of water does so. What is the chemical & the biological reason ...
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1answer
26 views

To understand synthesis of e-NOS and n-NOS with respect to Ca and calmodulin

I found this sentence in my notes interesting E-NOS and n-NOS are Ca-calmodulin dependent ferments. They are synthesized in small concentration as a response to physiological signals which ...
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1answer
7k views

What's the difference between protein and DNA behaviour during agarose gel electrophoresis?

I'm planning a science project about gel electrophoresis, and I'd like to know if there are any measurable, quantifiable (for example, things I could represent in a graph or chart) differences between ...
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1answer
127 views

Topology of protein

The domain structure of protein Z, which is composed of 180 amino acids, is shown in the upper part of the figure below. Protein Z is palmitoylated at a cysteine residue (the third amino acid) ...
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1answer
65 views

Identifying mutations in a yeast strain

Cells of a triple-mutant yeast strain (leu- his- trp-) were spread either on minimal medium or on minimal medium supplemented with various combinations of histidine, leucine, or tryptophan. The ...
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1answer
180 views

Determining limiting nutrients from a graph

The question was Which of the following statements is supported by these data? A. Phosphorus was the first limiting nutrient followed by nitrogen. B. Nitrogen was the first limiting nutrient ...
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1answer
4k views

Why is the function of lacA (encoding thiogalactoside transacetylase) not clearly understood?

It's almost half a century since the lac operon was discovered but isn't it weird that the precise role of transacetylase isn't clearly understood ? Here a wikipedia article with a link to a journal ...
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2answers
339 views

Question about production of CFTR protein

How do organelles such as ribosomes, ER, Golgi and vesicles produce CFTR protein and mucus?
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1answer
255 views

Creative ways to deactivate alpha-amylase taken from fungi

I can deactivate $\alpha$-amylase in ways such as extreme temperature controls, pH controls of the solution it stays in, or adding salt to the solution. However, are there any other unique or ...
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1answer
140 views

Lizards are sometimes called cold-blooded because they depend on their surrounding temperatures to keep them warm.

Predict how the composition of the cell membrane of a lizard might change from winter to summer. Justify predictions. Can someone please help me figure this out. Does it have to do with fluidity?
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1answer
172 views

Hydrophilicity and polarity [closed]

If any given molecule is polar, and is capable of hydrogen bonding, I can be sure that it's hydrophilic. However, are those two the only conditions that make a molecule hydrophilic?
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1answer
78 views

Why to choose a grammar from a lot of grammars that can describe structure of proteins? [closed]

Why do we choose a grammar from a lot of grammars that can describe structure of proteins? Usually, there are a lot of (maybe infinite) grammars that can describe one language. Why do we choose a ...
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1answer
265 views

Raphide toxicity in Pothos plant

Recently I found out that the common houseplant Pothos (Epipremnum aureum) is toxic to cats and dogs due to the presence of "insoluble raphides." I have a lot of these plants around my house and my ...
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2answers
87 views

What nutritious insects exist to farm that require the least attention?

What nutritious insects exist to farm that require the least attention? I'm looking to automate simply, in a self regulating way. Edit: To add detail, I imagine the insects would live densely in a ...
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1answer
140 views

Do Acyl Carrier Proteins and Conenzyme A have similar reactivity?

In terms of the reactions they undergo are they roughly equivalent groups?
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1answer
726 views

Amino acid characteristics that determine their chemical properties?

What chemical aspect of amino acids results in their having different properties such that the chemical and physical properties of polypeptides vary with both amino acid content and amino acid order? ...