14
votes
5answers
249 views
Are there any substance that are more dangerous at low dose than at higher dose?
It is commonly admitted that
The dose makes the poison
which means as a person, the more I take a substance, the more risk I take for my health.
There is even an indicator called LD50 (see ...
14
votes
1answer
116 views
Are there dextral/sinistral higher animals?
For example, almost every dog I've met in my life (more than 20 subjects) uses their right paw touching one while asking for attention. Can it be used as a criterion for calling them dextral? If not, ...
14
votes
1answer
178 views
What is the lowest pressure at which plants can survive?
What is the lowest pressure at which plants can survive? How the plants behave in a Martian-type atmosphere? Is there any plant that can survive such atmosphere?
Can a lichen grow at Martian ...
14
votes
2answers
234 views
Why Is Most Life Symmetrical Externally But Not Internally?
Mammals, reptiles, arachnids, insects, etc are all as far as I am aware symmetrical in appearance.
Take a human for instance, make a line from the top of our head right down the middle. However, ...
14
votes
2answers
177 views
Can methylation from DNA get copied to RNA during transcription?
Methylation on gene-body and 3'UTRs if copied to mRNA can potentially regulate post-transcription modifications or expression regulation. But I'm not sure if they are maintained after transcription or ...
14
votes
2answers
171 views
When does BLAST fail to align 2 DNA sequences?
This is an assignment that had confused me for a long time. So I think you guys who study computational biology might be interested. The original question is:
Find the two most similar DNA ...
14
votes
2answers
913 views
Why is glucose our primary source of energy?
Is there any evolutionary reason for glucose being the "main" molecule used as a source of energy, beginning with glycolysis and subsequently cellular respiration (after being converted to two ...
14
votes
1answer
318 views
Can siRNA induce DNA methylation in mammalian cells?
Some years ago Hiroaki Kawasaki and Kazunari Taira published an article called "Induction of DNA methylation and gene silencing by short interfering RNAs in human cells" in Nature:
In plants, ...
14
votes
1answer
207 views
Why does regular exercise increase brain volume?
It has been shown in several studies that regular aerobic exercise increases brain volume in aging humans. The changes were observed in hippocampus and were correlated with dramatic reduction of ...
14
votes
2answers
954 views
What actually happens when my leg 'falls asleep'?
Most people have experienced the temporary loss of feeling and tingling in their leg resulting from sitting in an abnormal position for a short while. Usually you get a loss of feeling in your leg ...
13
votes
8answers
3k views
Why have humans evolved much more quickly than other animals?
Humans have, in a relatively short amount of time, evolved from apes on the African plains to upright brainiacs with nukes, computers, and space travel.
Meanwhile, a lion is still a lion and a ...
13
votes
3answers
1k views
What causes the development of antibiotic-resistant strains of bacteria?
I understand bacteria have become resistant to antibiotics due to selection pressures, but how do resistant bacteria process antibiotics when exposed to it, compared to non-resistant bacteria. Also, ...
13
votes
2answers
241 views
How is temperature sensed?
Can anyone summarize the mechanism by which when an object of a given temperature is placed in contact with, say, the skin on a human fingertip, the average speed of the particles of the object is ...
13
votes
3answers
391 views
What is the most difficult feature to explain evolutionarily? [closed]
I wonder what are examples of organs/structures/behaviours/cooperation that evolutionary biologists themselves find most difficult to explain -- to explain how they could appear evolutionarily -- ...
13
votes
2answers
1k views
Harmless virus?
Is it possible for a virus to live symbiotically with its host?
Is the human body plagued with viral infections that do negligible harm, or even serve a beneficial role?
13
votes
4answers
653 views
Can two humans with 44 chromosomes produce viable offspring?
It is known that there are very few individuals having 44 chromosomes, not the usual 46 chromosomes.
One example is a male in China: the first article, the second article.
The other is a female in ...
13
votes
2answers
404 views
Does testosterone increase female sexual behavior?
According to my lecture notes testosterone generally increases sexual behavior.
Given that it's generally thought to be the male hormone I'm not quite sure whether they mean that it also increases ...
13
votes
2answers
780 views
What effect does vortexing have on a fluid sample that simple mechanical shaking does not?
Some protocols call for fluid samples to be mixed with a "vortexer" on the high setting. What effect does the vortexing have on fluid samples that mechanical shaking does not? Does it shear long ...
13
votes
2answers
163 views
Why is there now only one Salmonella species?
Once upon a time, I chanced upon an old microbiology book that detailed the rather colorful world of enterobacteria. Salmonella in particular stood out, as it seemed there were a lot of species: typhi ...
13
votes
4answers
360 views
Why did life not evolve to use radio?
We use electromagnetic communication everywhere these days. Cell phones, wifi, old-school radio transmissions, television, deep space communication, etc.
I'm curious about some of the possible ...
13
votes
2answers
188 views
Percentage of genome devoted to regulating gene expression
Recently I've been studying the p53 tumor suppressor gene as a model for regulation of gene expression. It's amazing how many different post-translational modifications are known to regulate p53 ...
13
votes
2answers
443 views
Why is 'Grudger' an evolutionary stable strategy?
I am currently reading 'The Selfish Gene' by Richard Dawkins, which I am sure many here have read. The topic are evolutionary stable strategies (ESS) regarding cooperation.
I apologise for the long ...
13
votes
1answer
2k views
What effect has changing pH and salt concentration on protein complexes?
I'm struggling to find peer reviewed literature that explains the effect of changing the pH and the salt concentration on protein/protein complexes in solution. What effect does the pH and the salt ...
13
votes
1answer
208 views
Do trees age on a microscopic level?
Most animals age via at least two mechinisms:
at a "macroscopic" level, basically wear and tear to the point where (on evolutionary time scales) it's more genetically advantageous to optimize for ...
13
votes
1answer
211 views
How did viruses come to be?
My question is out of curiosity and got me thinking. How did viruses with the head, tail and tail fibres actually evolve? These viruses look more like machines than biological entities. Are there any ...
13
votes
1answer
106 views
Are there animal models for Clostridium difficile that better replicate human infection than hamsters?
So I'm looking for some information on the infectious dose necessary to colonize a human with Clostridium difficile. There's no human challenge studies, and since it's not a foodborne pathogen, little ...
13
votes
1answer
154 views
Fibonacci sequence in nature, truth or just wishful thinking?
I'm reading a bit on the Fibonacci sequence in nature, be it the golden ratio or the golden spiral forming over and over again in biological structures, and then I came across this online article by ...
13
votes
0answers
99 views
Phagemid display
If I'm using a bacteriophage for phage display and I'm trying to avoid avidity effects by using a helper phage what would be the best way to maintain a large library size while keeping everything ...
12
votes
5answers
2k views
Can any protein be phosphorylated?
I am working with an Arabidopsis mutant with an F-box protein knocked out. It has been shown that F-box proteins targets must first be phosphorylated (Skowrya et al., 1997). I have heard of ...
12
votes
4answers
184 views
Online repositories of scanning electron microscope photographs?
I have looked at every single Wikimedia commons photo in the category 'scanning electron microscope'. Unfortunately, I could not find any other repositories of such photos, but I would readily look at ...
12
votes
3answers
337 views
How many human proteins have a solved 3D structure?
I was wondering how many human proteins have a solved 3D structure. Is there a database with only human proteins? I looked at pdb but couldn't find a filter.
12
votes
2answers
245 views
Why was it so hard to decode the corn genome?
My teachers growing up told me it was impossible to decode the maize genome. But yet its been done.
Why was decoding the genome so significant, and what made it so difficult?
12
votes
2answers
1k views
How will rising carbon dioxide levels in the troposphere affect photosynthetic producers?
Much discussion has been had about the affects of climate change on plantlife, but how will rising carbon dioxide concentrations affect the photosynthetic process itself? Since CO2 is a reagent in ...
12
votes
3answers
697 views
When has an organism evolved enough to be called a new species?
Imagine that we take a population of horses, split them in half and place them in completely different environments. The two species will evolve separate from each other and because the environment is ...
12
votes
3answers
155 views
When are population dynamics models useful?
When are population dynamics models useful? There seems to have been a lot of research about it, but how does it help? If I need data about how a population will evolve under what conditions, I need ...
12
votes
2answers
288 views
How Do Galls Form?
I am curious how Gall Wasps, bacteria and other organisms induce galls to form.
Specifically, what chemicals induce gall formation?
12
votes
4answers
328 views
Questions to ask to a panel of people that will be sequenced
Some genes have been shown to be associated with left-handedness.
Working with some clinicians, I've recommend them to ask their patients (whose genome will be sequenced) if they are "right or ...
12
votes
4answers
1k views
Does red light preserve your night vision?
A number of companies have started marketing LED lamps that can be switched to a red mode. The claim is that red light is less harmful to one's night vision. Given that our eyes are less sensitive to ...
12
votes
2answers
413 views
Is the EC50 of an activating protein for an enzyme a good indicator for the binding affinity Kd?
We work with a membrane protein system where measuring the affinity between the enzyme and the upstream activating protein has been difficult, and when measured in detergent solution, it is almost 100 ...
12
votes
2answers
1k views
Do men have significant hormonal cycles?
I know there's a similar question here. But that discussion dissolved into lunar cycle and a correlation with it. I want to find more towards the original question of is there a periodic hormone ...
12
votes
2answers
103 views
Relationship between our microbiome and personalized nutrition
Recently, it has been asked whether there are 'metabolic types' between humans that can benefit from a sort of personalized nutrition. One answer suggested that one discerning factor could be the ...
12
votes
1answer
1k views
Why does Penicillin only affect bacterial cell walls
I was quite fascinated by the feature Should Science Pull the Trigger on Antiviral Drugs—That Can Blast the Common Cold? in this month's Wired magazine.
They explain that Penicillin is effective at ...
12
votes
2answers
489 views
How does a brain distinguish stimuli?
If all the brain ever "sees" is action potentials, how do we know that one set of action potentials denotes a flash of light, another one signifies a loud sound, etc ?
12
votes
2answers
5k views
Possible? When a pregnant woman suffers an organ damage, fetus would send stem cells to the damage organ to help repair it?
I am quite sure that there is this blood-placental barrier between the mother and the baby so that nothing (except a type of antibody) can pass through it.
But I remember reading somewhere that when ...
12
votes
2answers
259 views
Which is more important for protein expression mRNA structure or codon optimization?
The field seems extremely divided on the debate. On one hand, artificial experiments have suggested that synonymous mutations don't correlate with gene expression but rather, the mRNA 5' structure is ...
12
votes
1answer
3k views
Why do mammalian red blood cells lack a nucleus?
How did the red blood cell in humans get to lose its nucleus (and other organelles)? Does the bone marrow just not put the nucleus in, or is it stripped out at some stage in the construction of the ...
12
votes
1answer
407 views
Does bioluminescence occur in humans too?
I read that Japanese researchers have developed very sensitive camera that recorded bioluminescence in humans; is it possible and if so what is the mechanism behind it?
12
votes
2answers
225 views
Do probiotics survive digestion?
Pretty much this. I've been wondering if any of the yogourt and other "health" foods containing living probiotic cultures survive digestion to populate our intestines? If so, is there peer-reviewed ...
12
votes
1answer
221 views
Quantum mechanics in biology
There is a growing interest in the applications of non-equilibrium quantum dynamics to describe biological processes (I'm not talking here about Penrose's old theories, but new stuff -- quantum ...
12
votes
1answer
478 views
Why do some mammals not have testes in a scrotum?
Coming from an evolutionary approach, Is the only purpose of a scrotum to regulate the temperature of the testes?
Knowing all mammals are warm blooded, shouldn't all mammals have testes in a ...
