texts: why plants cannot use atmospheric nitrogen?

texts:
Earth's atmosphere constitutes 78% of Nitrogen, then why do plants need to absorb Nitrogen from the soil. Why couldn't it possible for them to absorb the atmospheric Nitrogen like they do in the case of CO2.

Most of the plants relies on other sources to fix their Nitrogen, why couldn't be there a single plant which can absorb atmospheric Nitrogen ?

Is there any ancient plant which is considered to be using atmospheric Nitrogen ?

  I have done a simple research, I could only find that previously
  atmosphere is not so abundant with Nitrogen and plants developed
  mechanisms to use Nitrogen fixed in soil. So now they are following
  the same mechanism when Nitrogen is abundant in the atmosphere. Is
  this a valid answer ?


texts: I know that the cristae of the inner membrane can be tubular or vesicular but I would like to know what are the functions of each .


texts: Need for -70 degree temperature for Corona vaccine

texts:
Recent news of Pfizer vaccine for corona needing -70C temperature, made me thinking why such a low temperature is needed for mRNA based vaccine?
Are there other vaccine around which need such a low temperature?
NewsLink


texts: Why are we using upper teeth and lower lip on labiodental sounds?

texts: I came to wonder this when studying language (as well as other same theme question posted just few ago). For example the word "fantastic" we use upper teeth and lower lip to produce F sound, instead of using lower teeth and upper lip, which would work as well with a small practice.


texts:
Did we develop the sneezing mechanism to get rid of pathogens like bacteria and viruses in our nose?

Or did pathogens develop a way to make us sneeze to propagate themselves?

Or did we develop the sneezing mechanism, and then pathogens hijacked this pathway to benefit themselves?

I'm trying to understand why we sneeze so much when we get sick - is it our bodies trying to help us, or is it something the pathogen is causing to help itself spread? And if it's both, how did that happen?


texts: Is there a Pharmacology Textbook that Satisfies the Conditions listed in the Body of this Question?

texts:
The conditions are:

As extensive and explanatory as Goodman and Gilman's The Pharmacological Basis of Therapeutics, Twelfth Edition
With additional extensive and thoroughly explanatory information on drugs (e.g. flupirtine, piracetam, nefopam, etc.) that are used elsewhere in the developed/semi-developed (like Russia or China) world (e.g. European countries) but not in the US.
Additional information about the medically recognised (in some of the world at least) herbs cannabis sativa and hypericum perforatum (St. John's wort; recognised in Germany).

If there is no such book then the European (or a European, like for instance the British equivalent. So long as said equivalent comes in English) equivalent of Goodman and Gilman's will be accepted.


texts: Where would I find an up to date (last 6-7 years max) review on B cells? I've tried searching through pubmed with filters, cochrane library, medline and various other resources including searching old questions. A textbook would be fine too, but I'm not sure which one would give me detailed information. I'm a BSc student studying immunology. I'm not trying to create a war of "best" answers, any answer that fits these criteria I will accept.


texts:
There are several famous cases of great apes demonstrating a surprising degree of wherewithal in communication and tool use - even monkeys can learn some tool use from each other observationally, even if "teaching" would be an exaggeration.

The ready availability of this information will preclude me from bothering to cite a palate of examples.

Has anyone ever considered, as an experiment, taking such primates which display exemplary tool use in the lab and (at least partially) reintroducing them into the wild and seeing if (perhaps specially crafted) tool lessons learned form us humans propagates among their fellows?

If not, why not?


texts: Finding phylogenetic distance between sequences?

texts: I'm working on a piece of software that does comparative genomic analysis; and I found out in homology methods for functional annotation, it's preferable to pick the high scoring homolog from a distant sequence (i.e. not closely related to the query sequence in the phylogenetic tree).  My question is: why? and also could NCBI taxid for each taxon be used for approximating this distance? if not, then is there a simple way of making this binary decision (close, not close) when given two sequences.


texts: Data for giraffe subspecies population change over the time.

texts: Is there a historical data for the number of animals in the wild for every subspecies of the giraffe and where it could be found?


texts: What is the biochemical explanation for tingling and burning sensation in brain due to certain food?

texts:
Consumption of mustard (spicy English Mustard), wasabi and horseradish based food dressings usually result in a burning, tingling or freezing sensation in the brain/scalp and nostrils as the vapour goes through the nasal cavity.

I read somewhere, the checmical which gives the burning sensation is isothyocyanates. And some of the posts roughly mention about sinuses being agitated due to this chemical vapour.

How to explain this from biochemical and biology aspect? e.g. What sort of a cell reaction, if any receptors involved etc. (Appreciate an answer that is similar to the type of explanation here.)


texts: If the body continuously produces new sperm, how is there room for it?

texts: If you never ejaculated, how is there room for the constantly generated new sperm? I mean, is there always room for more?


texts: What's the role of SNP (Single Nucleotide Polymorphism) in a disease when there is no gene associated to that SNP

texts:
I am quite new to the field of GWAS (genome-wide association studies), and I'm combining GWAS results and single cell analysis on type-1 diabetes (T1D), to see the role of cell specificity on the disease.
However, I don't understand one aspect about GWAS results. The GWAS results lists all the significant SNPs (low p-value) from a certain study on a particular disease. After that, those SNPs are mapped to genes using either positional mapping (using windows), eQTL mapping, or even both.
However, some SNPs do not map to any genes using both positional and eQTL mapping procedure. Some removed SNPs even have a lower p-value than those which are mapped to genes.
Here is my question: since all the listed SNPs are supposed to be significant (tiny p-value), how can those SNPs which are highly correlated to the disease also show no association towards any gene. How do these SNPs give rise to the disease?
I would like to thank you in advance. Sorry if I'm using wrong jargon or anything, and please let me know, if you want any further clarification.


texts: Is the common house gecko poisonous to touch?

texts:
I live in India. Sometimes some common house geckos came in house and my family members kill them and I feel very bad (I even cried once ). They told me that It is very poisonous and toxic. If they fell in food or water, the water or food becomes toxic and would kill you. They told me that if you want to save them then catch them and release somewhere else but should I touch it?

I just saw a man on YouTube who handled it like it was no big deal?
I am talking about this gecko :-


texts: What does differentiation of B-cell mean?

texts: Does differentiation of B lymphocytes mean the formation of plasma cells and memory cells by matured B lymphocytes?


texts: What strange jelly-like thing is shown in the photo?

texts: What is shown in the pictures below? The photo was taken at the Australia's south coast (Queenscliff). The length of the thing is no longer than 50 cm... It doesn't move and has jelly-like consistency... My guesses were either some product (egg cluster or excrement) coming out of a mollusk, a torn part of some kind of sea plant or a part of a jelly-like creature...


texts: Are there any proven ways to increase the rate of bone remodeling in humans?

texts:
I'm not asking for anything specific -- just wondering if there's any data, studies, or etc. that show a possibility in increased bone resorption and turnover (bone remodeling/Wolff's Law) from certain procedures (whether it be diet, supplementation, drugs, surgery/experimentation, exercise/habits, etc.)

For example, comparisons between studies of people that show bone remodeling faster under different circumstances that can prove a specific method one can use to apply

By "increase" I mean anything that allows the human skeleton to be replaced faster some way


texts: I was looking at this graph of turnip peroxidase activity and I saw that they use units of 1/sec for enzyme activity. What does this unit intuitively represent and how is it calculated?


texts: The fungus in my profile pic is bright orange in a ball growing out of the cut off branches scar, also in a necklace.  There are egg shell white broken balls instead of the orange balls-suggesting the orange ball explodes and the seed depart leaving the white shell bottom.


texts: Why does blood come out of leach when salt is put on it?

texts: I know osmosis is the reason for the water to come out of cells - When you sprinkle salt over a leech, it creates concentration gradient and forces the water out of the cells. But why does a lot of blood come out too ?


texts: Shortest strings not present in the human genome

texts:
What length are the shortest strings of DNA not present in any known person's genome, and what are they?

And is there a database online by which I could find this out?


texts: Appropriateness of PCA to visualize clusters in genetic data

texts:
In many genetic studies, PCA is often utilized to examine genetic cluster in human populations. Rarely is the % variance reported for the components. With human data it's been my experience that the first three components (which are often plotted) tend to contain very little % of the variance. How meaningful are your visual results (i.e. clustering) when the first three components cumulatively account for only (say) 10% of the variance?

To answer this question, I constructed a theory based on the following assumptions.

One theory. For human, the proportion of variation within groups (i.e. same ethnic group) account for ~85% of the genetic variation within individuals. Conversely, the variation within populations (i.e. continental scale) account for only ~15% of the genetic variation within individuals.

Even though the first three components (i.e. PC1, PC2, PC3) contained only a small fraction of the total variance, most often the magnitude of associated eigenvalues can be 50 to 70 times that of higher components. In other words, the first three components can explain substantially more (50x-70x) variance than any other component when comparing by individual basis.

While sometimes these higher components do explain hidden substructure within groups, bear in mind that individuals from the same group has ~85% genetic variation among themselves. Hence, most of the higher components might just be explaining this within groups variation. For analysis of genetic clusters, this is of no interest to geneticists. These higher components can thus be treated as background noises. Geneticists are mainly interested in variation within populations, which often is very ancient and strongly separated. Thus, when population clusters are formed in the first three components, it can be argued that they form mainly due to the variation within populations.

Summary: The low variance (<10%) cumulatively accounted by the first three components can be justified by the fact that variation within populations is only ~15% of the genetic variation within individuals.

My question is: Does the theory to my own question seem reasonable?


texts: Calculating the frequency of a recessive allele in case of three segregating alleles

texts:
Is it correct to say:

A.  f(A) = p; f(a) = q
B.  p = f(AA) + ½ f(Aa)=$\sqrt{f(AA)}$?

Also,

  For a gene locus segregating more than two alleles, the frequency of
  each allele is the frequency of its homozygote plus 1/2 the sum of the
  frequencies of all heterozygotes in which it can occur.

For example, I have this data on blood-types from a population: 42,4% type A, 8.3% type B, 1.4% type AB, 47.9% type O. Plus we know that p(A)=0.250, p(B)=0,050, p(O)=0,692.
When I try to calculate p(O) in different ways, I get p(O)= $\sqrt{0.479}$=0,692
If I calculate p(O) as:p(O)= 0.479+½*0.424+½*0,083=0,7325
 As the result, I am getting two different frequencies for p(O). What am I getting wrong here?


texts: What is the role of potassium acetate in plasmid extraction?

texts:
What is the role of potassium acetate in the alkaline lysis method of plasmid extraction?

Earlier I was thinking its role is to shield plasmid DNA (the same as sodium acetate in genomic DNA extraction). When 100% ethanol is added, it the DNA precipitates and then we remove potassium ions from the pellet using 70% ethanol.

However, I have read that potassium acetate does not have the same function as sodium acetate in genomic DNA isolation but, rather, is a neutralizing agent which helps small plasmid DNA to renature.

I am bit confused about the role of potassium acetate and why sodium acetate cannot be used instead.


texts:
Context:
The vagus nerves supply the neck viscera, heart, lungs and gastrointestinal tract. They join around the oesophagus to form the oesophageal plexus.

Question: Would damage to one vagus nerve in the neck have significant impact on heart rate and gastrointestinal tract function?

Thoughts: If the heart and GIT lie below the oesophageal plexus, which then continue in the inferior direction towards the cardiac and gastric plexuses, then surely a major functional failure in either the heart or GIT would require damage to both vagus nerves (?). I'm trying to make sense of the effect of their fusion, and whether or not this provides a compensating mechanism in the event that one of the two nerves is damaged.


texts:
If other animals have more than 2 nipples, then why do humans have only 2 nipples?

Even my pet dog has more than 2 nipples.


texts:
The human body is amazing. But there seems to be some evolutionary changes that appear to not make sense regarding redundancy.

While not necessarily the primary reason for their existence, the human body has a great deal of redundancy.

Two eyes.
Two arms.
Two legs
Two ears
Two nostrils
Two lungs
Two kidneys
Two sets of teeth
A very large liver that can work in part.
Two brain hemispheres that can (to some degree) do the work of the other.
An appendix that is not critical.

But why do we not have two hearts? It would seem like a good idea to have two smaller hearts, together they work above optimally, but survival would be possible with one.


texts: Some species have different numbers of chromosomes, as we all know. Throughout evolution, how was a species able to survive with an extra chromosome? How was this organism able to breed successfully to form offspring with the additional chromosome?


texts: They are very big. About the size of my hand in length and I've seen two now. My cat brought one in from the Texas border region.


texts: Why do we suffer abdominal pain after we get very angry or stress?

texts: You also realize probably, when we get so much anger or high levels of stress, after some point we have terrible stomach ache, like really heavy pain. Why is that? How stress or anger can effect our stomach? What is the mechanism?


texts: Are humans known to be "poisonous" to any animal?

texts: Are there examples of non-herbivorous animals that could be poisoned if they feed on humans because of the composition of our bodies/blood?


texts:
I am thinking of mixing forest soil with water and water plants with that.

I was hoping that nutrients from soil would get released into the water, so in effect, fertilize the soil.

I am not sure if this works, since I am not aware in what chemicals P, K, Ca, Mg is "stored" in forest soil. If it is oxides that it should dissolve rapidly.

So, overall, is it beneficial to the plant to water them with water in which forest soil was dispersed?

Plant in question are tomatoes, peppers.


texts: How does a neutral allele change relative to a nearby allele under selection?

texts:
Suppose I'm looking at a gene being selected against (A) that's decreasing at a rate ($\Delta$P). If there's a nearby allele that is neutral (B) am I correct to assume that B will decrease with A at a rate of $\Delta$P*cM?

So for instance, if A and B are .5 cM from each other and A decreases from .8 to .4, will B decrease from .8 to .6 because there is only a 50% crossover rate between the two?


texts: Is reverse tonotopical organisation possible?

texts: In human cochlea tonotopical organisation is that higher frequency sounds are detected near the entrance whereas lower frequency sounds are deep inside the cochlea. Is this tonotopical organisation (high frequencies at the entrance, low - deep inside) justified by some physical or biological constraints or it doesn't matter and we could in principle have cochlea where low frequency sounds are detected at the entrance?


texts: How to determine sensitivity in a dose-response curve?

texts:
In a dose-response curve the % inhibition can be plotted against concentration antagonist. In our case, the effect of the antagonist is tested in different genetic variants of a microbe.

When trying to determine the potency of a drug on the different variants, I compared the IC50 values. The lower the concentration required for 50% inhibition, the more potent the drug.

When comparing drug efficacy, I compare the concentrations required to reach Emax or the maximum inhibition that each drug can exert - which turns out to be 100% inhibition.

To compare sensitivity, how does one proceed?


texts: How is the "fine mapping of pelvic regulatory region" done in this paper?

texts:
Could anyone please explain to be in very basic terms how Fig 2, and the associated text(located above the figure) is done? The jargon is too much for me to understand and I really need a simplified, step by step, version of the process to aid my understanding.

Here is a copy and paste of the text, the figure, and the figure description in that order from the paper:

"Fine mapping of pelvic regulatory region. To further localize the position of the cis-acting changes, we looked for the smallest chromosome region co-segregating with bilateral absence of pelvic structures in a cross between pelvic-complete [Japanese marine (JAMA) and pelvic-reduced (PAXB) fish (13)]. High-resolution mapping identified a 124-kb minimal interval, containing only the Pitx1 and Histone 2A (H2AFY) genes, which showed perfect concordance between PAXB alleles and absence of the pelvis (fig. S1A).

Recombination in natural populations can also be used to narrow the size of regions controlling polymorphic traits in sticklebacks (18). We therefore tested whether markers in the Pitx1 region were associated with the presence or absence of pelvic structures in lakes with dimorphic stickleback forms: benthic and limnetic sticklebacks from Paxton Lake, British Columbia (PAXB/PAXL), and pelvic-complete and pelvic-reduced sticklebacks from Wallace Lake, Alaska (WALR/WALC) (fig. S2) (13, 14). Microsatellite markers located in an intergenic region approximately 30 kb upstream of Pitx1 showed highly significant allele frequency differences in fish with contrasting pelvic phenoytpes (P < 10−35) (Fig. S1B and table S2). In contrast, markers around thePitx1 and H2AFY coding regions showed little or no differentiation above background levels. These results suggest that an approximately 23-kb intergenic region upstream of Pitx1 controls pelvic development. This region is conserved among zebrafish and other teleosts (Fig. 2A), suggesting that it may contain ancestrally conserved regulatory enhancers."

http://scienceintheclassroom.org/sites/default/files/stickleback_2.jpg

"Fig. 2.  (A) VISTA/mLAGAN (http://genome.lbl.gov/vista/) alignment ofPitx1 candidate region from pelvic-complete stickleback (SALR), medaka, and zebrafish. Red peaks indicate >40% sequence identity in 20-bp sliding windows; grey bars at topindicate repetitive sequences; and circles indicate microsatellite markers used in association mapping in fig. S1. (B) Reporter gene expression in transgenic animals. (C) Pel-2.5-kbSALR from a marine population drives tissue-specific EGFP (green) expression in the developing pelvic bud ofSwarup stage-32 larvae (36). (F) Detail of (C). (D and G)Altered Pel-Δ2.5-kbPAXB sequence from pelvic-reduced PAXB stickleback fails to drive pelvic EGFP expression. (E and H) A smaller fragment from marine fish, Pel-501-bpSALR, also drives EGFP expression in the developing pelvic bud of multiple stage-30 larvae. This region is completely missing in PAXB."

Source :http://scienceintheclassroom.org/research-papers/what-pelvis-can-teach-us-about-evolution/university

Paper:Adaptive Evolution of Pelvic Reduction in Sticklebacks by Recurrent Deletion of a Pitx1 Enhancer.  Chan et al.


texts: During the alcohol metabolic pathway, harmful by-products are made like acetaldehyde, hydroxyethyl, superoxide anions, and hydroxyl radicals. How do these toxic compounds harm our tissues? Many of these intermediates are the compounds that are responsible for hangovers, but are they also the molecular cause of liver damage?


texts:
I know that what I'm writing about may be a little strange, but as far as I know,when we are asleep, our human body is programmed to carry on biological functionalities in a really optimized way and we are less sensible to external stress.
So I wonder whether putting people in some state of induced coma for a long period of time (I mean for years) may reduce the effect of time and aging on their bodies to be able to awake them later ,almost as they were before undergoing the process ?

Note: I'm not speaking about the process of freezing bodies - only bare sleep.


texts: How can I estimate the CO₂ uptake of a plant?

texts:
I would like to make an estimation of the CO2 uptake of plants I cultivate, including, lettuce and aromatic herbs, such as thyme, basil, rosemary. What I want is to end up with a rough indicator for business purpose, not some super-accurate measurement.

Is there already average CO2 uptake data per plant type available?
Will this uptake vary drastically per plant type?
Can I calculate the estimate through a simple measurement (e.g. of plant weight) or does it require tight lab experiments? In the former case, how is that measurement made?

Please bear in mind I'm not a scientist, but and end-user of science. Thank you for helping me this question if needed.


texts:
The principle is that sum total of all allelic frequencies is 1.

Individual frequencies for example can be named p,q.In a diploid cell , p and q represent the frequency of allele A and a respectively . The frequency of AA individuals in a population is p2  as the probability of an allele A with a frequency of p appear on both the chromosomes of a diploid individual is simply the product of the probabilities. Similarly for aa it will be q2.Can anybody explain that how it will be 2pq for Aa?

I am getting it as pq.


texts: Can plants grow under extreme (>1%) carbon dioxide concentrations?

texts:
Related to but distinct from this question due to the concentrations involved.

While small carbon dioxide concentration increases can positively impact plant growth under some circumstances and at the same time negatively affect it under other circumstances, these changes are relatively small (doubling CO2 from 0.04% to 0.08%).

Is there any research on plants grown at extremely high (>1%) carbon dioxide concentrations in the air, assuming Earth atomspheric pressure? For the purpose of this question, assume that the plants are supplied with pH modifiers such as limestone in the soil to prevent soil acidification.


texts: How do the pharmacodynamics of the NSAIDs differ and are there "resistant" COX phenotypes?

texts:
I know that the non-steroidal anti-inflammatory drugs (e.g., aspirin, ibuprofen, naproxen) affect the enzymes cyclooxygenase (types I and II).

Is there any difference in the degree to which these drugs manipulate/inhibit the enzymes (I assume their affinities for COX-1 and COX-2 are at least somewhat different)?  Is there any evidence as to whether the the NSAIDs collect in certain areas of the body in a compartmental fashion?
Are there differences in fat solubility, etc., between the different drugs?

Finally, are there any known phenotypes of COX-1 and COX-2 enzymes that are present in the general population that affect the ability of these drugs to act?


texts: What is the impact of stress on the human body?

texts:
Can stress trigger any changes in the human body? I'd like to know more about things less commonly known than, for example: sweating and tiredness. What are the long term risks of chronic stress? Do stressful people have higher chance of having heart-diseases or affected by hair-loss, for example?
I'm also interested in how can an emotion induce physiological changes in our body?


texts: How genetically similar are worker ants from the same colony?

texts:
I've been reading https://en.wikipedia.org/wiki/Ant and it says

  If the egg is fertilised, the progeny will be female diploid; if not, it will be male haploid.

Since the males have only one set of chromosomes to pass on to the queen, all of their direct offspring (which can only be female) will contain all of their DNA. How similar is the DNA that the queen provides? Is there a high likelihood that there will be genetically identical individuals within a single colony, even if they were hatched at different times?


texts: The ermine's colour and geographical range

texts:
Ermines turn white during the winter, with only the tip of the tail remaining black. However, in the southern regions of the ermine's range it clearly doesn't get so white. Encyclopedia of Life says that:

  However, in the Netherlands, the animals are often only partially white.

Ermine's range is clearly much more southern than the Netherlands:

Wikimedia, stoat range

So I was wondering where does the border go, north of which the ermines are completely white and south of which they remain more brown? I understand it necessarily is not a clear cut line, mountains have impact and subspecies may differ, but I would assume someone must have mapped this. Or is it just weather related, will a southern ermine turn white if the winter is really cold?

I'm just asking this out of curiosity, but the question is rather relevant. Ermine pelt has a long history as an important trade item, and the most valued pelts must have originated on the white side of this line.


texts: Many times due to lack of sleep I felt discomfort in digestive tract.Why did it happen?Do lack of sleep affects the process of digestion?


texts: Why can't you taste food when you have a cold?

texts:
It is a common observation that food is tasteless when we have a cold. Why is that so?
What is the cause of inability to taste when we have a cold? Are the nose and ability to taste connected?


texts:
The other day, my teacher suggested we find out whether a chain of the following amino acid sequence would be able to form a coiled-coil:

N-KIAEVRAQYEDVANKVRLIVE-C

Now, I can see that the chain is not amphiphilic as it does not alternate between polar and non polar amino acids. But when I come across an exercise of this type, how do I determine if it can actually form coiled coils? I can feel this will be a question on the final test.
All help is deeply appreciated.


texts: Why proteins are not visible on my membrane after ponceau staining?

texts:
I have a problem in western blot that I can't resolve by myself.
When I am use to add 100 microgram of proteins for each sample but after running and transfer its impossible to me to see bands of protein.
What can be the reason of that?
Thank you for your help


texts: How significant is the genetic component of homosexual behaviour?

texts:
From some basic googling, I found that nobody has ever proven that people are born gay and that environment plays a great part in homosexuality.

I wish to know if there is a genetic component to homosexual behaviour. If so, how significant is that component (in some measure such as percentage contribution to the behaviour). What are other factors that play a role in homosexuality i.e. what constitutes environmental factors?


texts:
I have just discovered that my kitchen sink pipe has been leaking for quite some time (possibly months) which has resulted in water and food deposits collecting in my cupboard.

I smeared some of the residue onto a slide and looked at it under my microscope. I could see a large number of translucent organisms (visible at 40x magnification, they are roughly 100 µm in length). They all appeared to be of the same species although they varied in size and developmental stage. The 'adults' are quite long and look similar to maggots; they scrunch their bodies into balls and then stretch out in order to propel themselves.

Unfortunately I lack the equipment to take a photo of it but here's a rough sketch of what it looks like moving to the right:

Don't take the features too literally.

Can anyone hazard a guess as to what it might be?


texts: This 5X binding buffers where experiment participates in?

texts:
I saw 5X bingind buffer maded by;

100mM HEPES, pH 7.6
5mM EDTA
50mM ammonium sulfate
5mM DTT
1% Tween-20
150mM potassium chloride

which reaction helps this buffer? I don't consider to this buffer participates in which experiment by name. Although this buffer have another name but they writes just '5X bonding buffer'..


texts:
I'm reading this paper about how neurons can connect. Wikipedia says, typically neurons connect via axon (transmitter) and dendrites (receiver) but there are also special cases where dendrites connect with dendrites, axons with with another axon, neurons with no axon etc.

Now in the paper they refer to the soma-soma paired neurons and their strength of their cholinergic synapse.
Does that now mean that they neurons do directly interact via their soma? If so, how much different is that process to the generic axon->dendrite pathway?


texts: A question concerning the strength of synapses

texts:
Synaptic strength can be defined

  »as the average amount of current or voltage excursion produced in the postsynaptic neuron by an action potential in the presynaptic neuron«

Synaptic strengths and their changes depend on many factors and mechanisms, from LTP and LTD to STDP and STF and STD. Possibly, also neuromodulators should belong to this list – but maybe they shouldn't.

Assuming that synaptic strength is a well-defined quantity even when the synapse is at rest, the strength of a synapse is a continuous or non-continuous function over time, that ideally can be plotted.

Now I wonder whether there have been recordings and/or simulations of the synaptic strength of a single synapse as such a function over time - and how the plot would look like at different time scales: long term trends superimposed by shorter and shorter fluctuations?


texts: Why do some armadillos roll into a ball while others don't?

texts: My question is pretty simple that why do some species of armadillos (like three-banded) roll into a ball, while others don't?


texts: CRISPR guide RNA design and primer synthesis

texts:
I am trying to knockout huntingtin gene from HeLa cells (human epithelial cells). I used CRISPR explorer and benchling.com to determine the best guide RNA sequence that would bind to the target DNA sequence and cas9 could then make the cut. The gRNA I have is as follows:

GGAGGCCTCGGGCCGACTCG
Strand (-)

The next step for me is to design the primers with the following sticky ends

Forward primer: 5'-TTGTTGN(19)-3'
Backward primer: 3'-ACN(19)AAA-5'

The problem I'm having is writing the oligonucleotide sequence of the primers. Since the gRNA strand is negative, I'm assuming it's a 3'-5' sequence, hence the reverse of it will be the 5'-3' sequence, which I can then just use as the forward primer. Sequentially, I can take the reverse and complement of this forward primer sequence to then determine the backward primer. Is that correct? I appreciate all your help.

Thank you,
Abdullah Chaudhary


texts: Are there official criteria for an experiment to be considered statistically robust for publication in a decent scientific journal?

texts:
For a high school project, I investigated the effect of breathing meditation on teenagers. 15 students were asked to follow specific directions and meditate for 10 minutes a day for 8 weeks. Each week, their heart rate, ventilation rate, maximum lung capacity and blood pressure were measured with 5 trials. These measurements were also done prior to the meditation regimen.

My question is, to publish an experiment in a scientific paper, must there be a specific number of participants, trials, or time-length of the experiment?
This is to talk about in the discussion part of my report.

Please let me know what you know!


texts: How do you see the stage of the second meiotic arrest in oogenesis in the given video?

texts:
My old question raised this new question. After reading this page I can say now that metaphase is the stage in which the second meiotic arrest occurs within oogenesis:

  The oocyte is arrested again in the metaphase of the second meiotic
  division.

It is difficult to visualize the thing in my head. I could not find a video of specifically for oogenesis but probably the general model for meiosis holds true. The problem I am having is that I cannot see the arresting steps in this general meiosis video.

How do you see the second meiotic arrest of oogenesis in the above video?

I cannot even see clearly the first meiotic arrest. I only know that it is in prophase for the first and metaphase for the second.


texts: What are the best plants to cultivate yeast from?

texts:
I know that cultivating yeast from potatoes yields a good brewing yeast and that forms of wheat make good baking yeast, however; I have not seen much information on other useful plant yeast cultures. What are some of the other plants that offer potentially useful yeast cultures?

*edit : corrected my error in thinking yeast was produced by plants due to a answer given


texts: Is a corpse more flexible than a living person?

texts:
I read that the majority of humans have the muscular-skeletal potential to perform the splits that you see many gymnasts perform.  The reason a living person with no flexibility training can not achieve the splits is because the person's central nervous system (CNS) automatically constricts the muscle fibers of the legs when the legs move beyond the person's normal range of motion.  I read that this automatic CNS response is called the stretch reflex, and it is the CNS's way to protect the body from performing potentially dangerous movements.
So my question is: does this mean a body with a non-functioning CNS is very flexible?  For example, if I could not perform splits while I was alive, could someone position my corpse into the splits before the event of rigor mortis?


texts: Does every protein encoding gene necessarily have a transcription factor?

texts:
For instance, transcription factor gene A is responsible for activating gene B that encodes protein 1.

However, it is possible for genes like gene B to encode proteins without having transcription factors to activate them?

(Otherwise said, can protein encoding genes have no transcription factors)?


texts: What do groundhogs and other subsurface-tunnel dwelling creatures do in heavy rains to avoid harm?

texts:
I notice groundhogs and many other tunneling creatures in my yard, the same yard which became pretty flooded during heavy rainfall. I don't see wildlife out during rain storms, but not long after, they emerge and return to their regular daily behavior.

What do the creatures living in tunnels underground do to avoid harm from flooding? The kind of harm I imagine them being susceptible to is drowning or damage to their tunnel. It could be that their tunnels get destroyed and they simply dig their way out and make a new one, in which case the only remaining question is how they avoid drowning while sheltering underground from storms. Even that question may be moot if they don't in fact shelter underground from storms, but instead shelter somewhere less susceptible to inundation like up in a tree.

I originally had groundhogs in mind with this question, but if possible, I'm interested in answers that apply to various tunnel dwellers: groundhogs, chipmunks, ants, ground wasps, etc. I know many ground-dwelling insects live there for the moisture it provides, and during storms they'll come to the surface to enjoy the moisture there and avoid drowning (e.g. slugs, worms), but I don't think this applies to all insects and certainly doesn't apply to mammals who generally seek shelter from the rain.


texts: Why doesn't water enter my body through my anus or genitals when swimming?

texts:
So when we swim, we can make water not enter through our nose and mouth, simply by holding our breath. However, the mouth and the nose aren't the only cavities. What about the anus and the genitals? They obviously can't "hold breath", so how do they stop water from entering?

I thought the reason is gravity, but then, people would be killed when diving because your butt is facing up, against the gravity.

Another explanation might be that the internal pressure is higher than the external one, but I fail to recall any organ that creates the pressure..


texts:
On a walk through I’ON Swamp/Natural Forest in Mt. Pleasant, SC, we came upon this snake. We did not get too close for fear it may be poisonous.

It had a very dark brown/taupe exterior with almost a diamond shaped head. It had a reddish, orange belly. It was ~3-4’ in length and fairly large girth.


texts: Does sickle cell anaemia protect a victim against malaria?

texts:
My biology textbook says that a person with sickle cell anaemia is less prone to malaria. Why is that so?

I'm guessing that its because the malarial parasite needs human RBCs for completing its life cycle. So are the sickle-shaped RBCs inhospitable to the parasite? In what way exactly?


texts: How do the High-Energy Electrons During Chemiosmosis Come from Water?

texts:
On Pg. 199 of Campbell, this is stated.

Both* work by way of chemiosmosis, but in chloro- plasts, the high-energy electrons dropped down the transport chain come from water, while in mitochondria, they are extracted from organic molecules (which are thus oxidized).

*Both refers to the to chemiosmosis in mitochondria and in chloroplasts (during photosynthesis).
My question is, how do the high-energy electrons in the transport chain for chemiosmosis come from water? Aren’t these high-energy electrons derived from light harvesting done by the light-harvesting complexes?


texts: Why pain caused by blunt objects vanish after some time and return at the event of touching?

texts:
Background

When any bone/muscle of body is hit badly by a blunt object, it hurts pretty bad of course for some time. But, after some time the pain goes off completely or to some extent.

Then, if we touch the wounded spot, the terrible pain returns.

Why?

If the pain goes off as the healing process of severed tissues, blood capillaries, then why does it return at the event of touching?

My reasoning: I think there is a sophisticated pain mechanism responsible for this phenomenon.Firstly, pain warns our nervous system to be cautious against any new injury. As time goes on, sensory adaptation diminishes the pain. But the event of touching is a new pressure for the blunt wound.So, the pain comes back again. But, I need well-referenced answer to support my view.

Papers: The most relevant paper I've found till now: 1 which is behind paywall


texts:
Mammals like seals often dive and can remain under water for more than 70 minutes.

How do seals know when is it the time to come up?


texts: Why does alum work on blisters in the mouth/cold sores?

texts: Alum used to be an age old tradition to treat sores in the mouth and it worked beautifully.Foes anyone know why Alum works on sores in the mouth ?


texts:
I'm about to make some Graphene Oxide and in the paper for Tour's Method it uses a centrifuge to isolate the solution. However it requires $319g_0$. What does this mean, and will a centrifuge with 3300rpm suffice?

https://www.researchgate.net/publication/234084399_Graphene_oxide_for_effective_radionuclide_removal


texts: Did the jackal (wild African dog) evolve independently or with some form of human domestication?

texts:
The jackal is a wild dog species in Africa that feeds on carrion, much like the hyena.
Pop science, as it were, would make us believe every dog species emerged as a result of human domestication. Was that the case for every dog species? Or might some have evolved independently?
Another way to phrase this would be: Do wild dog species have a completely wild heritage, or did they branch off of some previously domesticated line?


texts: What is Chronic immobilization stress (CIS)?

texts:
I am trying to self study BNDF a little bit when I found this article:

  Abstract Stress impacts multiple systems within the CNS, including the
  hippocampus. A key molecular mediator in hippocampal functions,
  including learning and memory, is brain-derived neurotrophic factor
  (BDNF). BDNF mRNA is reported to be decreased following chronic (every
  day) immobilization stress (CIS) in the rat, however the effect on
  protein is unknown. Utilizing a mouse model of CIS, the hypothesis
  that total hippocampal BDNF protein, in addition to BDNF mRNA, would
  be decreased was tested. The effects of intermittent (alternating day)
  immobilization and cold stress on hippocampal BDNF protein levels was
  also examined.

  In this study it was demonstrated that CIS results in a small (8 per
  cent decrease relative to non-stressed controls), but significant (p =
  0.0013) decrease in the exon coding for mature BDNF (exon VI). In addition, there was a significant (34 per cent, p = 0.005) decrease in
  the mRNA coding for exon I in the stressed animals. Contrary to
  expectations, however, CIS resulted in a significant (116 per cent, p
  = 0.0087) increase in hippocampal BDNF protein levels. Furthermore, both intermittent immobilization and chronic cold stress both
  increased BDNF protein levels. Chronic stress, therefore,
  differentially regulates BDNF mRNA and protein levels in the
  hippocampus. Copyright © 2004 John Wiley & Sons, Ltd.

I'm really curious what they mean with CIS: Chronic immobilization stress.
I can't find anything on the internet that actually explains what this is.


texts:
I found this spider (~10 mm body length) indoors on a wall (South-East England) and I was wondering what species it was.

My first guess is false black widow, but I can't be sure.

I'd be grateful if anyone could help me out.


texts: Why are there two mature sequences of microRNAs in miRBase entries?

texts:
In the miRBase database entries generally show a stem loop sequence and two mature sequences. For example the entry for hsa-mir-15a gives three sequences: (1) the Stem-loop sequence hsa-mir-15a, (2) Mature sequence hsa-miR-15a-5p, and (3) Mature sequence hsa-miR-15a-3p.
What is the difference between the two mature sequences? Does the stem loop structure divide into two different miRNA species?


texts: How does a bone know the final shape it has to attain (and then maintain)?

texts: How do osteoblasts and osteoclasts share information with each other to maintain this shape?


texts: I'm creating a project in which I can measure brainwaves (more or less like EEG). Since I'm not a medical student im having a problem finding the origin or most prominent regions for measurements of alpha and beta waves. I have researched on the internet but can't find a definite solution. So can  someone please tell me the exact origin or the most prominent region (active region) of our brain where  the alpha and beta waves can be measured reliably??( Like ocipital region or frontal temporal etc)


texts: Is O4I2 sufficient to reprogram cells (ie induce pluripotency)?

texts:
Is exposure to the chemical O4I2 (ethyl 2-((4-chlorophenyl)amino)-thiazole-4-carboxylate) sufficient to reprogram an adult cell back to pluripotency?

They sell this chemical online for pretty cheap. My question is, if I wanted to start a colony of induced pluripotent stem (iPS) cells, would I only need to buy this or are other reprogramming materials required?


texts: By what mechanism can two chromosomes fuse?

texts: What condition(s) would likely exist which could cause 2 chromosomes in the newly fertilized egg of a placental mammal to fuse? Assume this is more likely than having the same chromosome pair fuse in an individual egg, as well as an individual sperm.


texts:
I am a newbie in biology and I am simply trying to discover the field of genomics.

Consider the question - Are genetic tests accurate?

I don't believe they are as the genes may not provide the complete information or maybe there are other genes responsible for a particular trait but they may not be known at the point when the test is conducted. This may not be the right answer though — I simply wish to understand from people here as to what they can say about the accuracy of these tests. If they are not accurate, can you explain why that is the case?


texts: Why don't we dribble tears through our nose?

texts:
Basal tears are tears produced by the lacrimal gland and they lubricate the eye. They are then funneled into the lacrimal sac and then from there into the nose eventually.

If this is the case, why don't we constantly dribble out tears from our nose? Where do the tears go?


texts:
I'm reading an essay on the creating of the Mammalia zoological classification (Londa Schiebinger, The American Historical Review, Vol. 98, No. 2 (Apr., 1993), pp. 382-411).

It contains the statement (page 386)

  All mammals (including the whale) have hair, and it is still today considered a distinguishing characteristic of mammals.

Is that statement correct? Do all known species of whale and dolphin have hair? If so, where is it? You can't see it on the surface of the animal, is it internal like we have nostril hair?


texts: How long does it take for a person to lose all offsprings due to inheritance?

texts: From this I know we will only inherit some genetic informations from parents, which is about 50 percent. But the problem is, gene has finite size, after some generations a person leaves only $0.5 \times 0.5 \times 0.5$ parts of genes to the offsprings, and it will be casted into zero. My question is, how long does it required for a person to lose all genetic information in the world?


texts: What kind of ants are these? Are these venomous?

texts:
I found these ants on a small mango tree in front of my home. Could someone identify them for me.

Length: 2-3 cm

Location : North India(Chandigarh)

Temperature: 21-24 degree celsius

More info: They built a home out of leaves of the tree.


texts: due to hypersecretion of growth hormone why only terminal growth takes place?

texts: why only terminal growth takes place in acromegaly and gagiantism, due hypersecretion of GH?


texts: Does drying meat in the sun make digesting it easier?

texts: I was looking into the relationships between man, fire, brain size, evolution, etc. and I learned about other methods of food preparation that eased digestion, but did not use fire. Then, this question popped into my head. Specifically, I am wondering how much easier is sun-dried meat to digest; how much of a benefit is gained in the amount of energy needed for the digestive process?


texts:
I found this "thing" crawling across my drive way. Never seen anything like it and no one I know can identify it.

Was about 4 to 5 inches long and 1/4 wide. It move some what like a worm in that segments of it's body seemed to move to propel itself forward very slowly.

I have a video as well if that would help but it is one my cell phone. I live near Gettysburg PA.


texts:
I have a quick question regarding micelles. I have tried googling the answer but can't seem to find the answer. The question is, during digestion lipids are emulsified into micelles in order to increase their surface area for digestion but my question is, why don't the micelles stick together and form a clump which would decrease it's surface area?

Thank you.


texts: Do ants also use the Earth magnetic field?

texts: A lot of animals, specially birds use the Earth magnetic field to orientate on their flight across the Earth. Now some scientist suggest that ants has on their antenna a kind of magnetite crystals by which they also can use the magnetic field. But for what would and could an ant use this huge magnetic field, while they just walk for only meters a day?


texts: "Most bacteria have at least one cell wall"

texts:
In the first answer to How do we find antibiotics? @Ashafix claims that

  Most bacteria have at least one cell wall

Does this mean that there are bacteria with more than one cell membrane? Which are those and how does that look/work? Are there different milieus in the different compartments?

Cheers


texts:
I'm trying to design a primer for Gibson assembly.  My gene of interest is on a plasmid, and I want to copy that gene, and put it into a different plasmid.

I am unsure how to design my primers for PCR. I know that I need 2 sets of primers (4 total).

Backward and forward primer to copy my gene out of the plasmid that holds it.
Backward and forward primer to copy the plasmid.

I also know that I need to create complementary regions of overlap between my gene and the plasmid I want to put it in.  How do I do this?

Here is the plasmid and the gene. I want to place the gene in between the biobrick prefix and suffix.

Here is what primers I think I need:

For the plasmid I want to put the gene in, my primers should be

Forward: ATTCGCGGCCGCTTCTAGAG
Reverse: CTGACGCGGCCGCTACTAGTA

Primers to copy gene and add overlap

Reverse: ATCATTTCAAATTCGTCCATCTCTAGAAGCGGCCGCGAAT
Forward: AATTAGAAAGAGATTATAATACTAGTAGCGGCCGCTGCA

Here is the gene

IodoY TyrRs

Here is the plasmid I want to put it in. I am using geneious, but I think for this purpose, word works just fine.


texts: I've seen several of these insects near my house in southeast Michigan this summer, including the one seen here feeding on a green bottle fly. What are they?


texts: Is it a valid generalization that kinases catalyse reactions involving energy transfer and utilization?

texts:
The Wikipedia entry for kinase states that "a kinase is an enzyme that catalyzes the transfer of phosphate groups from high-energy, phosphate-donating molecules [such as ATP] to specific substrates".

ATP is the energy currency of the cell, so, would it be accurate to say that a kinase catlayses reactions involving energy transfer and utilization within a cell?


texts: What are the tests performed by NASA's Mars rovers to establish that life could survive on the planet?

texts:
I am particularly interested in the Mars Rovers, which are out there trying to find life. Do they believe that the tests they perform are sufficient to verify the existence of life (Also please mention about the tests). How do they accommodate for the possibility of life forms different from the conventional carbon based as that of Earth?

I am really curious to get these answers, please explain.


texts: Epidemic threshold on a directed network

texts:
I am trying to understand the equations used in a paper

  (https://www.nature.com/articles/srep00469.pdf)

Mainly I'm trying to understand how the epidemic thershold was calculated using the equation:
$$I^{t+\Delta t}_a = -\mu\Delta tI^{t}_a + I^{t}_a + \lambda(N^{t}_a - I^{t}_a)a\Delta t\int d{a}'\frac{I^{t}_a}{N}+\lambda(N^{t}_a - I^{t}_a)\int d{a}'\frac{I^{t}_a{a}'\Delta t}{N} $$

From the supplementary information (https://media.nature.com/original/nature-assets/srep/2012/120625/srep00469/extref/srep00469-s1.pdf (eq.17)), I get that $$I^{t}_{a} - \text{number of infected individuals in the class a, at time t}$$
$$N^{t}_a - \text{total number of individuals with activity a, at time t}$$
$$\lambda - \text{transition probability, } \mu - \text{recovery probability}$$

I understand that first two terms $-\mu\Delta tI^{t}_{a}$ and $I^{t}_{a}$ represent the number of recovered individuals, and number of infected individuals of class $a$ at time $t$ respectively. Rest of the equation is a mystery however.

In the supplementary information eq.18, we get:
$$\int daI^{t+\Delta t}_a = I^{t + \Delta t} = I^{t} - \mu\Delta tI^{t} + \lambda \langle a \rangle I^{t}\Delta t + \lambda \theta^{t}\Delta t$$

where $\theta^{t} = \int d{a}'I^{t}_{{a}'}{a}'$, I don't understand why we get rid of N in the $4^{th}$ term and how we obtain a moment of a distribution from the $2^{nd}$ term to get this. We then get:

$$\theta^{t+\Delta t} = \theta^{t} - \mu\theta^{t}\Delta t + \lambda \langle a^{2} \rangle I^{t}\Delta t + \lambda \langle a \rangle \theta^{t}\Delta t$$

Which again makes no sense to me, I feel like there is a lot of steps missing here. From here onward it's just dark magic for me, no clue what's going on.

Then this is written as differential forms:
$$\partial_tI = -\mu I + \lambda \langle a \rangle I + \lambda\theta$$
$$\partial_t\theta = -\mu\theta + \lambda \langle a^{2} \rangle I + \lambda \langle a \rangle \theta$$
From that somehow the Jacobian is calcuated as
$$J = \begin{pmatrix}
-\mu + \lambda \langle a \rangle &  \lambda \\
\lambda \langle a^{2} \rangle & -\mu + \lambda \langle a \rangle
\end{pmatrix}$$

Eigenvalues:
$$\Lambda_{(1,2)} = \lambda \langle a \rangle - \mu \pm \lambda \sqrt{\langle a^{2} \rangle}$$

Threshold:
$$\frac{\lambda}{\mu} > \frac{1}{\langle a \rangle + \sqrt{\langle a^{2} \rangle}} + \mathcal{O}(\frac{1}{N})$$

I would appreciate if someone could explain this to me, I have been trying for few weeks now, and it just makes less sense more I look at it.

Now that's the threshold on an undirected network, if I were to calculate the threshold on a directed network how would I do that? Would it be something like this:

$$d_{t}I = -\mu Ia + \lambda(N_{a}-I_{a})a\sum_{{a}'}I_{{a'}}\frac{m}{N} + (N_{a} - I{a})\lambda \sum_{{a'}}{a}'I_{{a}'}\frac{m}{N}$$


texts: Cell life: division for immortality or reproduction with aging

texts: Are the two cells that are derived from one cell, ‘twin sisters’ or a ‘mother and a daughter’?  In other words, can a cell really be divided to live an "immortal" life or is cell reproduction the reality of cell life that accounts cell age difference between two successive generations, cell aging-associated senescence in cell reproduction, and cell line survival after the death of old cells.


texts: Menstrual cycle and luteinizing hormone (LH)

texts:
What is the effect of increased concentration of LH on the follicle at the start of the menstrual cycle?

I know that increased levels of FSH at the beginning causes follicles to mature and release estrogen, but I cannot seem to be able to find what the effect of increased levels of Luteinizing Hormone at the beginning of the cycle would have.


texts: Are genes known or at least conjectured to evolve cyclically ?

texts: I observed recently that some people born the same year in not too distant areas (say, in the same country whose size is not too big, like France) share similar phenotypical features, for example they look like each other though they are not of the same family. If confirmed, this would suggest that some alleles are more common within a given period, and hence that the global evolution of the human genetic pool could be statistically determined. One can go one step further and see the considered genetic pool in a given range as a quantum-like system governed by some kind of Schrodinger's equation. I think here of a theoretical framework like Laurent Nottale's scale relativity that could explain these similarities. Have such questions been considered so far?


texts: Why do humans circulate monosaccharides instead of disaccharides as in plants?

texts:
Plants transport food mostly in the form of disaccharides like sucrose but humans transport them in the form of a monosaccharide -  glucose.

What is the reason behind this ?


texts:
Can you please tell me what type of insect eggs these are? I found them in the corners of my office kitchen behind boxes and cardboard. Found them in between the broom bristles. Found them along the edge of the wall. There are quite a few of them.
If you could please provide me some tips on how to avoid getting these eggs or killing off the main insect would be helpful.


texts:
Why are many anti-malaria drugs gap junction antagonists?

My professor recently just mentioned that many of the anti-malaria drugs block gap junctions. i am wondering if this blocking is important for stopping malaria, and how blocking gap junctions is anti-malarial. How does this effect connect to the mechanism of malaria?


texts: How do I know whether or not a nuclear gene is single copy?

texts:
As a part of a phylogenetic study, I need to find a nuclear gene that meets the following requirements:

Single copy gene;
Highly variable gene;
Gene longer than 400 bps;
Gene that gives information at the species/genus level in Gastropoda.

My candidate genes are the following: 5.8S, 18S, 28S, ACT, APN54, EF-1alpha, endo-1,4-beta-glucanase, GSTM, GSTO, GSTP, H3, ITS1, ITS2, MCP, MYO.

However, I do not know where to find whether or not they are single copy.


texts: What is the name of the bug that emerging from a wood chip like cocoon?

texts: We found it on the wall of a home at West Palm Beach Florida. Is this a kind of infestation or a sick tree near the house fall on the wall?


texts: Does evolution only give rise to traits that confer fitness? In other words, does the existence of a trait imply it's conferring of fitness? If not, what are some counter examples?


texts:
Looking at my computer's fan I can say that a lot of dust is collected on it not less dust should be collected in the lungs, not to mention some inhaled parts of food.

How the lungs clear themselves from dust, smoke, food particles?


texts:
Just started learning about aerobic respiration today, specifically Glycolysis.

We were told that aerobic respiration produces 38 ATP, while anaerobic respiration produces only 2.

However, we're also told that:

Glycolysis produces 2 ATP
Link reaction produces 6 ATP
Krebs cycle produces 24 ATP (18 from NADH, 4 from FADH, and an extra 2)

This only adds up to 32 ATP, so where is this other 6 coming from? Or is this information incorrect.


texts: These photographs have been taken in Warora, India. Could someone please help identify this bird?


texts:
I know how plasmids can replicate independently of the main genome and know that they confer various properties to the bacteria and are useful in conjugation.

My question is - what is the advantage of plasmid replicating on their own? (Would there be any disadvantage if they were controlled by the main genome instead?)


texts: What was the first gene(s) found to code for ncRNA

texts: I could not find a source that states what the first gene found to code for ncRNA was. Someone told me, however, it was a gene that coded for either rRNA or tRNA. To this point in time I have had no other confirmation that this is true.


texts: Photosynthesis and thermosynthesis(?) in plants/organism

texts:
A while back I thought to myself: if plants could absorb the entire(or most of) light spectrum as opposed to a narrow range, would it be better/absorb more energy/etc. Recently i read that was not the case because any higher on the spectrum and it could knock electrons loose(or something like that) and any lower and it would generate heat instead. Also the article said that plants focus on specific wavelengths for photosynthesis, hence the colors.

If heat is the main issue, then is it possible to turn the heat energy into usable chemical energy? Potentially allowing plants to absorb a much larger range on the light spectrum? And if the plant could absorb heat as well, would it be cool/cold to the touch?


texts: In what situations, when reacting to impressions, are the signals sent directly from the thalamus to the hypothalamus?

texts:
Normally when humans react to impressions, signals are being sent through different centers in the brain through the chain of:
Impression ${\rightarrow}$ Thalamus ${\rightarrow}$ Cerebral Cortex ${\rightarrow}$ Hippocampus ${\rightarrow}$ Amygdala ${\rightarrow}$ Hypothalamus ${\rightarrow}$ Reaction

In some situations, the middle parts are skipped, handling feelings, long-term memory and understanding. The chain in the case consists of:
Impression ${\rightarrow}$ Thalamus ${\rightarrow}$ Hypothalamus ${\rightarrow}$ Reaction

Under what circumstances does this alternate path of reacting happen, and what effect does it have on the outcome of the reaction?


texts: What is the speed of neurotransmitter release and receptor binding in a neuronal synapse?

texts:
Obviously neural signals travel at extremely high speeds, but I'm wondering how much that speed is affected by the release and binding time of neurotransmitters.

If my sources are correct, a well myelinated axon generates an action potential with a speed of roughly 119.807 m/s. How much does the speed of neurotransmitter release by the presynaptic neuron and binding to the postsynaptic neuron's receptors impact that speed? In other words, I am wondering how much the total speed of a neural signal from one neuron to another is affected by the time it takes for the first neuron to release neurotransmitters and the second neuron to receive the neurotransmitters and propagate an action potential within its own cell.

I assume it takes at least some time, but exactly how much does it slow the signal down?

Thank you for your answers.


texts: On average how many genes / alleles do people share?

texts:
I am curious about how much more a child can be alike to one parent than the other. If a child were to inherit all the alleles that are shared between both parents from one parent, but inherit all alleles from the other parent which the first parent doesn't possess, wouldn't this make the child genetically more uniquely similar to the second parent?

This question would be aided by understanding of how many alleles on average a person already shares with another person. Taking into account regional areas probably yield more similar people, I would imagine the average couple would share more than two randomly chosen people on the planet.


texts: What areas of the brain are involved in doing arithmetic operations?

texts: Do neuroscientists already know what areas of the brain are involved in mental calculations? Has any fruitful research been done on that or not yet? Do you think that if we understand what areas of our brain are responsible for doing arithmetical tasks we may one day have the ability to improve someone's calculation skills by non-invasive methods?


texts: Are there any enzymes in cytoplasm to help the newly-synthesized polypeptide to form tertiary structure?

texts: Polypeptides made by ribosomes which attach to rER will go into the rER to form the tertiary structure. Those polypeptides made by free ribosomes usually stay in cytoplasm. So are there any enzymes in cytoplasm to help them to form tertiary structure?


texts: "Antibiotic resistance" equivalent in archaea for selection during cloning

texts:
I'm beginning to work with halophilic archaea and I'm trying to figure out a good way to select for cells that have taken up a plasmid.  Obviously, one can't use antibiotic resistance since they are not bacteria.

Is there anything equivalent I could use for + selection in cloning experiment for halophilic archaea? Usually I would use NeoR and Neo plates but that won't work...


texts:
I found may such jellyfishes on the Hua Hin beach in 27.11.2018. They measure around 25 cm.

Since I'm more botanist, I have big problem to identify it. Google doesn't help me a lot (spent 3 hours googling and nothing).

Anyone know latin name?


texts: What is this red and white striped wasp?

texts: I saw this dead wasp in a park in Hong Kong.


texts: Can birds touch their wing tips together either in front or behind (not above and below)?

texts: Can the tips of a birds wings touch so that it would form a ring if view from above or below? I suspect it might be a bird of prey and at the moment it is picking something up from the ground but I can't find a good photo.


texts: What are the positive effects of wrongful antibiotic use on a viral infection?

texts:
I categorically accept that bacteria differ from viruses; so antibiotics DON'T help in viral infections. I also read this and this; so no need to explain this. I've read about the negative effects (eg exacerbation of antibiotic resistance); I ask only about the positive effects here, and NOT for reasons to exploit antibiotics for infections not due bacteria.

Yet I myself have witnessed that some people with viral infections feel better after wrongly taking antibiotics? and so asked about this first on Cognitive Sciences SE.

Initially, I suspected only some placebo effect, but this enlightened me on the side benefits of antibiotic consumption for a viral infection and motivated this question, now that my original question on psychology has revealed the relevance of biology.


texts: Correlation between genome size and mutation rate?

texts:
Martin Nowak in his book "Evolutionary Dynamics" talks about a given correlation between genome size and mutation rate.

What correlation does exactly exist between these two concepts?

Is it a linear correlation?
What is the coefficient of correlation?
Does this correlation exist in many different taxa?

One will need to make whether we talk about mutation rate per base per generation or for the whole genome.

Some references to accompany claims are welcome!


texts: What is the mechanism by which passive immunity works?

texts:
My idea is that passive immunity can be used to cure an individual who is infected with a certain disease. For example, for someone infected by clostridium tetani, you would inject them with an antiserum. The antibodies give protection against bacteria, until the active immune response takes action. In this link (http://pmt.physicsandmathstutor.com/download/Biology/A-level/Notes/Edexcel-IAL/Unit-4/6-Infection-Immunity-and-Forensics/Set-A/Vaccines.pdf), page 3, the graph shows that the level of antibodies in the blood actually rises after injection! To me, this naturally begs the question, what is the mechanism by which passive immunity operates (because I want to know why the level of antibodies rise in order to understand the situation dynamically)?

[Note: would I be correct in saying that a short answer would be that the level of antibodies rises because the active immune system is stimulated due to the enhancement of phagocytosis by macrophages when the antibodies attach to the antigens? My book states that release of antibodies (by B-cells) that bind to the antigen is required to allow the macrophages to engulf the pathogen with the specific surface antigen.]


texts: How to Determine Sufficient Time for Melanoma Survivor to Be Considered Low Risk?

texts:
Regarding melanoma, how do we determine the minimum amount of time that a patient is disease free for them to be considered low risk? We are attempting to do survival analysis on RNASeq data from melanoma patients.

We are at the stage where we need to adjust the threshold that dictates how long a "Disease Free" patient needs to be disease free to be considered a low risk case. Is 5 years a good parameter or is it too conservative?
Academic sources for protocols, or similar examples are encouraged.


texts: How to interpret dual luciferase assay result (RLU)?

texts:
I performed a dual luciferase assay using pGL3 firefly luc as experimental reporter and pRL-TK renilla luc as internal control (Promega assay kit). I used a manual luminometer to analyze my sample. After that, I got following result:

Sample        RLU (LARII)                   RLU (stop & glo)

A               1978                               902

B               1702                               1101

C               1952                               980

As I am doing it for the first time, I cannot understand the result. I want to know, how can I interpret this result? There is no unit. RLU stands for relative luminescence unit; but what it actually means? What is the method to compare the results of different samples? How can I understand expression efficiency? I have read some papers but unfortunately my concept is not being clear.

Where can I find useful information and guidance about it?


texts: Can anyone remind me of the name for the inter-scapular space on the back?

texts: It's one of those names which are often said not to exist, like philtrum.


texts: Is the human ovum visible to the naked eye?

texts:
I'm a student in a field unrelated to biology or medicine, however I very much enjoy reading about it. I just read in Merck Manual that

Human cells vary in size, but all are quite small. Even the largest, a fertilized egg, is too small to be seen with the naked eye.

A very quick google search (caused by basic elementary school biology knowledge) results in Wikipedia article that says The egg cell is typically not capable of active movement, and it is much larger (visible to the naked eye)

Did I misinterpret something here, or I'm reading an unreliable source?
Merck Manual was reccommended for learning about these things since it's maintained by MDs so I was just wondering. Thanks!


texts:
When ions diffuse out passively or are actively transported out of the ascending loop of Henle, do those ions just hang around or do they go into the circulatory system and leave the kidney.

I ask because I know the medulla must stay salty but I always assumed that those ions were then entering blood vessels for another purpose.


texts: Is there any math formula that can be used to describe shape of leaves?

texts: There can be great variation in shape of leaves. Neverthless they are fairly simple shapes. How far are we in describing the shape of leaves in a mathematically rigorous way? Do we have a general formula that can be used to describe all shapes of leaves (or, at least, a reasonably large subset)?


texts: Are "sympathetic nerves" the same as "cardiopulmonary splanchnic" nerves?

texts:
I've gathered from a number of sources (e.g., Patel (2015), Wikipedia, and here) that the sympathetic nerves leaving the sympathetic trunk to innervate the heart and lungs are called "cardiopulmonary splanchnic nerves".
However, I've noticed that both the 14th and 15th edition of Tortora & Derrickson's A&P textbook seem to suggest that these nerves are simply called "sympathetic nerves," even though they make reference to abdominopelvic and adrenal splanchnic nerves more specifically.  See below from Tortora & Derrickson (2013):

...Then, the axons of the postganglionic neurons leave the trunk by forming sympathetic nerves that extend to visceral effectors in the thoracic cavity (Figure 15.4). Sympathetic nerves provide sympathetic innervation to the heart and lungs.

Here are subsets of images from Patel (2015) [LEFT] vs Tortora & Derrickson (2013) [RIGHT] (my emphasis):

My question: Are "Sympathetic nerves" the same as "cardiopulmonary splanchnic" nerves?

Are these names interchangeable? I can't find further evidence supporting Tortora and Derrickson's usage of this phrase in such a specific manner to refer to postganglionic neurons leaving the trunk to innervate the heart and lungs. Are they acting rogue? Are they simplifying? Any insight would be appreciated.

Cited works:
Patel, T. R. 2015. "Chapter 36 - Anatomy of the Sympathetic Nervous System." Pages 495-506 in Tubbs, R.S., Rizk, E., Shoja, M.M., Loukas, M., Barbaro, N. and Spinner, R.J. eds. Nerves and Nerve Injuries: Vol 1: History, Embryology, Anatomy, Imaging, and Diagnostics. Academic Press.
 Tortora, G. J. and B. Derrickson. 2013. Principles of anatomy and physiology, 14th edition. John Wiley & sons, Inc.


texts: How to eliminate a prozone reaction or hook effect

texts:
I was doing revision for my test and came to a question that asks how to eliminate a prozone reaction or hook effect. I think done through refrigeration but one of my friend says it by diluting the antibody and another says it's by concentrating the antibody by centrifugation.
So just wondering if someone can help me to get to the correct answer.


texts: Is it possible to produce bread using only microorganisms?

texts:
I am wondering if it is theoretically possible to produce bread using only microorganisms. If one lists all the chemical components, proteins fermentation time, etc., is it then doable to combine the needed (engineered) microorganisms in one bio-reactor, let them do their thing and produce the wanted product (bread in this case)? Maybe there is a review paper on this topic but I haven't found it yet.

My background: Molecular biology, I know too little about microbiology and bio-reactors, etc.


texts:
Found in Kustaankartano, Helsinki, Finland in June 2015.

(for closeup view, copy image URL and open in new window and then zoom in)


texts: Is death by cyanide the same as suffocation?

texts:
I started the night off by reading about "what does drinking the Kool-aid mean" this lead to a wikipedia article which described the horrors of the Jonestown cult mass suicide/murder in the 1970s. This was followed by reading about some of the references cited, and eventually me coming up with a biology question.

The murder/suicide used Cyanide. Reading the description of how it is described here: http://indianapublicmedia.org/amomentofscience/how-cyanide-kills/ makes me wonder if death by Cyanide is equivalent of suffocation. I think a biology background, doctor or nurse would be suited to answer this question.


texts: Why do we need to amplify DNA sequences?

texts:
I am learning about biotechnology. I have no education in biology or chemistry and am simply interested in the subject of biotechnology.

I am wondering why we need to have multiple copies of a piece of DNA in order to do something with it (ie. PCR)? Why is one piece of DNA not enough? Is machinery not precise enough to work with one piece of a DNA sequence in order to do something with it?

I can understand that an experiment may fail. In that case, make 8-16 copies for assurance. But why an extraordinary (billions) amount of copies? What practical use does it have? What applications require there to be an extraordinary amount of DNA to be succesful? Do the billions of copies just increase the speed of the experiment by being able to quickly "fish out" a piece of DNA? I just can't quite grasp the idea.


texts: What benefits do sloths and manatees gain from algae growth on their fur/skin?

texts:
Slow moving sloths and manatees have green algae growing on their fur/skin.  Are there any other animals that have algae growth on them, and does the algae benefit the fitness of these animals?

Source: Canadian Museum of Nature

Source: wildlife.org


texts: How long can a unicellular organism live without nutrition? What happens after that? Does it depend on the domain?

texts: Say I have three unicellular organisms: a eukariote, a bacterium and an archaeon. If I cut off nutrition from them at the same time, how long will it take for them to die? What will their death look like, and do they actually need to die? If so, why?


texts: How would inserting a nonfunctional protein impact fitness of an organism?

texts:
Producing proteins costs energy, and producing longer proteins costs more energy than shorter proteins. Producing proteins which have no function, would therefore presumably negatively impact the fitness of a bacteria in culture. So my question is this:

Is there a way of modeling how much a nonfunctional protein would impact fitness relative to the wild-type which doesn't produce this protein? In other words, what is the cost — in terms of fitness — of just producing a protein, if you ignore all the other effects of the protein inside the cell?

How much would the length of the protein effect it? would the impact on fitness vary linearly with the length of the protein?

This would probably depend on many different parameters, I'm just not sure what all of them are and how each of them would factor into the final result. For instance, it would probably depend on the level of expression of the gene (which sigma factor would impact this especially).

I posted a similar question a while ago, but I've reworded it based on feedback from last time. If it helps you to think of a specific organism to answer the question, by all means, do so. Let me know if there is any literature already on a question related to this one!


texts: If cells regularly renew, why do we have scars?

texts:
Question may sound bit poetic but I have a pretty basic question here: Often we get a minor wound and cells renew and quickly "cover" it. But when we have deeper wounds, often they leave behind scars. Why does it happen?

I was researching around and saw this comment on a related question:

  That's not true - some cells turn over quite quickly, others take months or years, others never replicate.

But how come we get some wounds "completely filled", while others leave scars on almost the same skin/body part? And ok, if a deeper cut has resulted in inner (different type of cells) being damaged, why do we find the scar on epidermis?

Thanks a lot for your guidance.


texts: How is Elysia chlorotica classified as an animal capable of photosynthesis?

texts:
Elysia chlorotica is a kind of sea slug. Technically, it's an animal. However, it undergoes a process called kleptoplasty, which is the absorption of chloroplasts from algal prey cells which are then used to produce food. E. chlorotica uses these chloroplasts for 9-12 months at a time, and manages to keep them functioning. Also, E. chlorotica has absorbed some algal genes, however, none are related to photosynthesis, and none are expressed.
So, Elysia chlorotica is a sea slug that is capable of photosynthesis, but only after taking chloroplasts from its prey.
What I'm wondering is how do you classify something like this? I know E. chlorotica is currently listed as a mollusc in kingdom Animalia, but what if it fully absorbed its preys genome and was able to sustain chloroplasts on its own? Would E. chlorotica be considered a plant or an animal? Or something else? Is that even possible?
I know this is a lot, and maybe this forum isn't the right place for my questions, but any insight would be greatly appreciated!


texts: What is the depression between bridge of nose and brow called?

texts: In a human being, what is the depression often found between the bridge of the nose and the brow called?


texts: Can an octopus survive if one of its three hearts stops working?

texts:
While reading the book "The Soul of an Octopus" by Sy Montgomery, I learnt that Octopuses have three hearts. This is very fascinating. According to a Wikipedia article,  two of the three are used to  pump blood through each of the two gills while the third pumps blood through the body.

So, my question is can an Octopus survive if one of these hearts stops functioning?


texts:
We found this seashell on a Mediterranean beach in the south of France. While most of the shells we found were quite intact, this one caught our attention.
It is light and littered with tiny holes, and thicker than other shells we found.
Is this due to erosion in the water? How did the shell look like before the ocean changed it? Was the shell simply exposed to the water for a longer time?


texts: Is a naive immune system equally able to handle new antigens as an educated one?

texts:
This is a variation of the "does the immune system run out of memory" question.

Here's a (possibly imperfect) thought experiment: You take two twins. One of them lives in a bubble from birth. One of them is Mike Rowe from Dirty Jobs, and gets exposed to all sorts of antigens as well as vaccines. When they are 30 years old, you expose both of them to an antigen that neither has seen before. What happens?

PS: Note that while this example is illustrative, my question is really about whether there is any way at all in which the response of a naive immune system to a novel antigen is different from that of a very educated immune system (which has also not seen the antigen before). For instance, would the same amount of antigen be required to stimulate the immune system? Would the antibody count several months or years post-exposure differ?


texts: Can two denatured DNA strands reassociate?

texts: What matter if I increase the temperature to 95°C. So double-strand DNA denatured into two ssDNA, and then I decrease the temperature to room temperature. Are they able to reassociate after denaturation?


texts: How can neuronal signals faithfully be reproduced by scalp electrodes?

texts:
There is a skull barrier (and possibly other layers too) between the brain and the scalp. I have seen people trying to extract EEG signals from the scalp by connecting electrodes and interface it to other devices. But how do these weak signals pass through these many barriers and reach the scalp electrodes? Also, "scalp cells" will have their own dynamics, right?

I simply don't understand how can we even get a approximate measure of electrical signals inside brain from scalp.


texts: Why does ostrich meat look and taste more like beef than chicken?

texts:
Some time ago I tasted ostrich meat, and what was amazing to me was that the meat very much resembled beef, much more than it resembled chicken, turkey or duck meat. And even more than lamb and pork resemble beef.

The resemblance is both in look, both raw and grilled, and in taste (only tried grilled). I would have thought that the meat of related animals would have similar taste. Why is it that the meat of an ostrich, which is a bird, doesn't taste like that of other birds?

Warning, the following links are to pictures of meats!

A picture of beef
A picture of ostrich meat
A picture of chicken meat


texts: Why are mammals the only animals with pinnae / outer ears?

texts:
Yes, I know owls have feathery "ear tufts", but these are less suited for hearing and more for display.

And I find it hard to believe that animals like dinosaurs or other cursorial archosaurs would not rely on sound as much as a mammal would. It's just too useful of a sense.

One potential clue is the fact that most non-mammal tetrapods appear to use electrical tuning to discern different sounds, whereas mammals use the hair cells of their longer cochlea to mechanically discriminate sound. I feel like this is related but not completely connected to why a fleshy outer ear structure that can collect and focus in on the direction of a sound.

Why did the pinnae evolve in mammals and why are they the only ones with such a structure?


texts: Subset of Protein Crystal Structures (from PDB)

texts:
Is there a well-accepted subset of the Protein Data Bank set of protein structures that:

Has only "high quality" structures (may be differing metrics of this; e.g. resolution, size, or structural completeness)
Has minimal redundancy (e.g. nothing with exact sequence identity from the same species)
Is still as large as possible, spanning as many molecules and species as possible
[Optionally but better] Is not too biased (e.g. certain classes of proteins are highly over-represented in the PDB)

It is possible to download the entire PDB and make up rules for myself, but this seems like something people might have already considered reasonably extensively. I'm hoping for a dataset I can just download and cite, in the best case. :)


texts: Does Topiramate work by supplanting Pyridoxal phosphate in enzymes?

texts:
I have seen it said that the precise mechanism of action of migraine medicine Topiramate is not known. But I certainly see a resemblance between that molecule and PLP (Pyridoxal phosphate, the activated form of vitamin B6).

A significant similarity is that both have an "offshoot chain" (Topiramate's sulfamate taking the place of PLP's phosphate) where PLP's phosphate is what binds it to enzymes in the first place, and both have a more electronegative element in the middle of what would otherwise be a six-carbon ring, apparently important in the typical PLP enzyme reaction.

I have been wondering if Topiramate supplants PLP in the enzyme glutamate decarboxylase, changing the reaction into a deamination. This would deplete glutamate, causing the pill's migraine relief, and the deamination could even cause Topiramate hyperammonemia.
If it does the same or similar to serine hydroxymethyltransferase, which is also PLP dependent, it could cause glycine deficiency, thus collagen deficiency - and this would even explain Topiramate hair loss.
When you look at it this way, it's frankly hard to imagine the mechanism of action is anything different. Have I stumbled upon it? Or has this been suggested already?


texts: What is this feather like bug with no legs?

texts: Seen on leaf in North Texas, USA in April 2017. Critter will attach itself to any object put next to it.


texts: Is there a good easy protocol for extracting proteins (enzymes) from fungal mycelium?

texts: I quantify the enzyme (polygalacturanase) activity by DNSA method. To determine endo-polygalacturonase activity I'm searching for a good easy enzyme extracting method. Any suggestions for a suitable buffer?


texts: Can herbs absorb harmful substances leached in water supply

texts:
I have small herb garden (parsley, coriander mint and basil) that is watered from below by a hydrophilic filter using capillary action from a reservoir. This filter allows water soluble nutrients to be fed to the herbs.

The manufacturer of the filter use a special propitiatory additive in the filter that allows for excellent water flow. I need to know the the harmful implications of the material as they have stated the unknown "additive in the filter is not FDA approved". They will not tell us what additive is to protect their intellectual property.

My question is that will the herbs absorb the additive regardless assuming the additive is leaching into the water. Say that 1 ppm (parts per million) of substance X is in the water. Will the herbs absorb that and propagate it to their leaves. If so how much of the substance? (very rough estimate will do)

TIA, Dave


texts: Why do some people find vegetables so repellent when evolutionarily they should find them an attractive and thus tasty food?

texts:
Why do certain people (especially kids) find vegetables so "repellent" when evolutionarily they should find them an attractive and thus tasty food?

I ask this question because if Darwin's theory of evolution is true then foods like vegetables that us human beings have been eating and attaining better health from eating for millions of years should have a taste that accordingly attracts us to them.


texts: Why do cell membranes have a lipid bilayer instead of a monolayer?

texts:
Many cells have a cell membrane composed of two layers of lipids. Why is it that they have two layers and not just one?

What purpose do this arrangement serve?


texts: How are lophotrichous flagella of helicobacter pylori produced?

texts:
I am thinking the mechanism is something like first adhesins (mucinase).
Howevever, this does not seem to be enough.

How are the flagella of H. pylori produced?


texts:
Rigor mortis sets in due to non-functional "ATP powered calcium pumps" as a result of which the calcium ions stream out & the muscles remain in a suspended animation state.

But, it's a frequent observation (as can be seen from a coroner's report) that the time for rigor mortis to set in depends on external temperature, like it's earlier in summer, but late during winter.

So why this fluctuation?

Wikipedia has got an answer, but it's too brief.

  When conditions are warm, the onset and pace of rigor mortis are sped
  up by providing a conducive environment for the metabolic processes
  that cause decay. Low temperatures, however, slow them down.
  Therefore, for a person who dies outside in frozen conditions rigor
  mortis may last several days more than normal.


texts:
Wikipedia says :

  The contents of these micelles (but not the bile salts) enter the enterocytes (epithelial cells lining the small intestine) .....

So, where do the bile salts go? Additionally, what prevents them from being absorbed by the plasma membrane?


texts: How might IVF (and related technologies) alter epigenetic marks?

texts:
I was reading up on KCNQ1, which encodes a voltage-gated potassium channel, and I discovered that it happens to be only maternally expressed. This is regulated by KCNQ1OT1, a non-coding RNA, which is also epigenetically regulated (expressed only paternally). Mutations in KCNQ1OT1 are associated with Beckwith-Wiedemann Syndrome (BWS).

Further reading led to the discovery that there are ART-related (assisted reproductive technology) cases of BWS due to loss of methylation at KCNQ1.

However, this article found epigenetic stability of KCNQ1OT1 methylation in cultured human embryonic stem cells, which leads me to think that KCNQ1 might also have been properly methylated.

So what exactly are assisted reproductive technologies doing that can disrupt inheritance of epigenetic marks (that culturing hESCs doesn't do)? (Is this understood for any gene?)


texts: What happens to drug metabolism when CYP450 enzymes are presented with two substrates

texts:
What happens when two substances, both substrates for Cytochrome P450 metabolism, are both present in the bloodstream?

For example, with sertraline and cannabidiol (CBD), if someone took a sertraline tablet and later used CBD, how does the presence of two CYP substrates affect drug metabolism? Does one drug inhibit the metabolism of the other? What happens to blood levels of the drugs? Does the order of administration matter?


texts: What is the energy consumption of an insect quantified?

texts: Allegedly humans have an average power consumption of 97.2 watts, but what about something smaller like a housefly or an ant? What is their energy consumption measured in watt?


texts:
Other than CO₂ and Methane what other gases do humans produce or emit?
For example, does  skin decomposition, or aerobic respiration emit any special gases that people don't normally realize or know about.
I ask because of a discovery I made during research is that while being poisonous to the central nervous system, methanol is a natural endogenous compound found in normal, healthy human individuals.
One study found a mean of 4.5 ppm in the exhaled breath of the subjects. https://iopscience.iop.org/article/10.1088/0967-3334/27/7/007


texts:
Is active transport required for all living cells to function?

I was under the impression that if a cell doesn't have active transport, it either would lose molecules through the membrane and not be able to maintain a proper gradient, or molecules would be trapped inside the membrane (waste) or outside the membrane (food).


texts:
My understanding was that all neurons and their synapses of worm c.elegans are already listed.

As source of this map I'm using following databases (both should contain same information):

Connectivity Data

Database of Synaptic Connectivity of C. elegans for Computation

In both databases, neuro-motor neuron VC6 (aka VC06) has no synapses to any other neuron. This is surprising for me.

Is connectome of this animal finished? If it is, are these two databases up to date? Finally, if answer to previous questions is "yes", any explanation about this "isolated" neuron ?


texts: How can birds keep their eyes moist during flight?

texts: Mammals have an upper lid and small mass  of tissue in the upper corner known as nictitating membrane. This helps keep the eyes clean; birds can moisten their eyes in flight using this membrane without blinking. How does this work?


texts: Do animals feel emotions, or display empathy?

texts:
Since we can't know much of what's going on inside an animal's brain, can there still be a consensus among zoologists on whether animals feel emotions, display empathy, care, etc.? Or is it disputed?
To clarify what I said since commenters asked for clarifications: Of course I don't mean SENSES (touch/vision/taste...) and also I do NOT include humans.

A suggested definition of emotion:

  An emotion is a feeling such as happiness, love, fear, anger, or
  hatred...the part of a person's character that consists of their
  feelings, as opposed to their thoughts. (Collins Dictionary)

An example of emotion:

  No one doubts that dogs know when they are in trouble,” writes de
  Waal, “but whether they actually feel guilty is a point of debate.”
  According to a study by Alexandra Horowitz, the canine guilty
  look—“lowered gaze, ears pressed back, slumped body, averted head,
  tail rapidly beating between the legs—is . . . not about what they
  have done but about how their owner reacts. If the owner scolds them,
  they act extremely guilty. If the owner doesn’t, everything is fine
  and dandy.” (Greater Good Magazine, University of California, Berkeley)

Empathy:

  Empathy is the ability to share another person's feelings and emotions
  as if they were your own. (Collins Dictionary)

Example of empathy:

  Macaques refused to pull a chain that delivered food to themselves if
  doing so also caused a companion to receive an electric shock.[48][49]
  This inhibition of hurting another conspecific was more pronounced
  between familiar than unfamiliar macaques, a finding similar to that
  of empathy in humans. (Wikipedia: Emotions in animals)


texts: What is a good set of notes to study human's eye mathematically?

texts:
I want to learn about the human eye. I could read a lot of online literature about it.

However, ideally I would like to study human's eye by solving some maths exercises. I suspect people have done this before. How would we have glasses otherwise?

Maybe you know good maths notes + PROBLEMS that would give me an insight into how an eye works?

The notes don't have to comprise a whole course. One chapter is enough, as long as there are some maths exercises attached.


texts: Can crows see in ultraviolet? If so, does their plumage look different in UV?

texts:
Apparently birds which appear identical to the human eye can look quite distinct under UV light. Additionally, drab looking birds might have more "spectacular" looking plumage when considering wavelengths outside of the visual spectrum.

Question: In the specific case of crows, (1) can crows see in the ultraviolet range? (2) is the plumage of crows still monochrome when considered in the UV spectrum? Is it dichromatic?

Google seems to return very little about this, although this random person claims that crows can see in UV and their plumage does not monochromatic under UV, while this article says they can not see in ultraviolet. Neither provides citations for their claims, and I am not familiar with the academic literature on this subject. Any help would be appreciated.

This question seems related inasmuch as crows seem black to the human eye. However, I know that some animals can see in UV, and am curious about whether this extends to crows.


texts: Effect of pH on protein solubilty and denaturation

texts:
I'm a little bit confused about the influence of pH on proteins.
Increasing or lowering the ph will give the protein a net positive or net negative charge, respectively. However a lower pH or higher pH will cause the protein to denaturate --> more hydrophobic amino acids will become free to interact between different proteins --> less solubilty.

let's clarify my question

take a look at the following figure:

this figure indicates that a lower or higher pH then the Pi will increae the protein solubility. However the Introduction to this article, for example, cites papers to support the following statement:

  Changes in pH are shown to trigger formation of amyloid fibers and aggregation

the figure and the article are inconsistent in my opinion, so I'm definitly missing something. The first figure indicates that protein solubilty will increase when the pH becomes higher (then the pI). However the article statement indicates that an increase in pH will cause the proteins to aggregate, so lowering solubilty right?


texts: What is the structural/chemical difference leading to different shapes in facial/head/pubic hair?

texts:
Different hairs have different shapes, thicknesses, properties.

What exactly is different between these types of hairs? a previous post implies that the root of the differing length (pun intended) is the rate at which the skin sheds the hair. However, this doesn't explain the different degrees of curliness, thicknesses, and textures.


texts: Do the eggs for larger litters come from the same meiosis events, or different ones?

texts:
There are some species of animals that give birth to more than one pup at a time. In these species, are the fertilized eggs all from one or a limited group of meiosis processes, or are they from different ones?

To illustrate the idea, take for example a case where some animal ends up with seven offspring in a litter. Do the original eggs come from different meiosis events?

Meiosis   Meiosis   Meiosis   Meiosis   Meiosis   Meiosis   Meiosis
   |         |         |         |         |         |         |
   V         V         V         V         V         V         V
   1         2         3         4         5         6         7

Or from a smaller set of events?

  Meiosis     Meiosis
 / |  | \     |  |  |
V  V  V  V    V  V  V
1  2  3  4    5  6  7

I am aware that, at least in mammals, that egg cells are actually produced long before they are used, and pooled for later use:

Meiosis  Meiosis  Meiosis
   \\\\    ||||    ////
    VVVV   VVVV   VVVV
    =====Egg Pool======
    |  |  |  |  |  |  |
    V  V  V  V  V  V  V
    1  2  3  4  5  6  7

I do not have any idea how this would work for other types of life though, like birds, reptiles, or fish. How does it work for those sorts of life?

I am mainly interested in this to understand how the mother's chromosomes are represented in the offspring. Are all of her chromosomes guaranteed to be represented in at least one offspring?


texts:
What is overdiagnosis ?

I have searched this Wiki result but didn't understood at all.

Can you please explain the first two line of Wikipedia :

  Overdiagnosis is the diagnosis of "disease" that will never cause symptoms or death during a patient's lifetime. Overdiagnosis is a side effect of screening for early forms of disease.

Also

What is over treatment ?
Are overdiagnosis and over treatment same or different ?