All Questions
3
votes
3answers
134 views
Why do neurones use chemical signalling at synaptic junctions?
Problem. When a neurone fires, it sends an electrical signal that jumps down the axon via the nodes of Ranvier very rapidly. At a synaptic junction, chemical brownian diffusion signalling with ...
3
votes
1answer
76 views
Are there natural selection experiments that quantitatively agree with theoretical modeling?
Has anyone ever conducted an evolution experiment and quantitatively compared it to theory? For example, has anyone ever put bacteria in a million petri dishes filled with antibiotics and calculated ...
2
votes
0answers
25 views
Eye color genetics
I am trying to find a model to link the phenotype eye color to its genotypes.
I know that there exists a simple model from Davenport, which explains {brown,blue} eyes. Further, there is an extended ...
1
vote
0answers
34 views
Electron transport in granal stacks
See paper for distribution of PS-I and PS-II within grana
As explained in the above paper, the PS-I complex is primarily located within non-appressed thylakoid region and stroma lamella, while PS-II ...
1
vote
0answers
81 views
Is eating salt dangerous for the brain?
I read somewhere that eating a lot of salt will raise blood pressure, which will in turn damage brain tissue. This is because water molecules gather around salt ions, thus making it harder for the ...
2
votes
1answer
50 views
What is the relationship between UV wavelength and penetration depth into human skin?
Some background - Some recent research has strongly suggested that UVA penetration into the skin is far more dangerous than UVB, a very good example is this paper by Agar et al. (2004).
My query is, ...
4
votes
3answers
46 views
Is there any source for raw data of SNP genotype frequency?
On sites like SNPedia, some pages contain the frequency of the SNP in question in different populations, based on published research. I'm trying to write a script that takes 23andme data and compares ...
4
votes
1answer
37 views
Photosynthesis regulation
I read about the regulation of Calvin cycle by thioredoxin which activates key enzymes essentially by converting disulphide linkages on inactive enzymes into sulfhydryls. Another regulatory mechanism ...
4
votes
1answer
49 views
How can I save bacillus strains on filter paper without an -80 degree freezer?
I want to save my bacillus strains but I don't have access to a -80 degree freezer. What are possible alternatives?
0
votes
0answers
40 views
Understanding SIR models in epidemiology
We are doing research on a SIR model of an epidemic. For one of the subsections, we are talking about saturation content rate of a human. We would like to know if anyone has an understanding of ...
1
vote
2answers
43 views
Which texts are good for beginners to understand evolution on the genetic scope?
Are there good texts to study the evolution, how it works, and how mutations and changes lead to evolution of the organism ?
And how does the information increase through the long time using ...
2
votes
1answer
72 views
How is consciousness linked to the brain?
Could the brain be working without consciousness? Does the brain interact with consciousness? Alternately, is it that consciousness can't really control the brain, and you only have the impression ...
1
vote
1answer
31 views
Blood circulation and blood pressure in different tissues
The volume of blood coursing the blood circulation is approximately five litres. A typical vein will stretch about eight times as much as corresponding artery. Because veins have high capacitance, ...
1
vote
1answer
20 views
Can the excessive consumption of mineral water lead to kidney stones or other health issues?
I heard that drinking too much mineral (bottled) water could lead to problems such as kidney stones because of the high amount of minerals in it. Is it true? If so, what is considered to be excessive?
...
1
vote
1answer
28 views
Deep diving in mammals
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?
1
vote
2answers
27 views
Are there beneficial genetic mutations identified by consumer DNA genotyping?
I'm looking at services like 23andme, and see that they identify a wide variety of genetic-based risks, like predisposition to diseases, hair loss, cancer, etc.
Are there a more "positive" DNA ...
1
vote
3answers
40 views
Blood pressure during exercise
What happens to blood pressure when we exercise ? Does it increases , decreases or remains the same? If it does increases , why are blood pressure patients recommended to exercise ?
31
votes
2answers
586 views
Is there any evidence that sexual selection may lead to extinction of species?
Darwin suggested that sexual selection, especially by female choice, may counter natural selection. Theoretical models, such as a Fisherian runaway process, suggest that evolution of preference and ...
4
votes
1answer
123 views
Are there any side-effects from a mosquitoes extinction?
Suppose that we have the ability to make mosquitoes extinct, what would the side-effect of such extinction be other than the fact that there won't be any mosquitoes left? Is it worth it to make ...
6
votes
1answer
2k views
Mitosis in human body
I've heard that stomach lining has the fastest reproducing cells and the brain has the slowest.
Where in the human body does mitosis occur and at what rates do these cell reproduce? Is there a chart ...
5
votes
2answers
65 views
Why are males more likely than females to have autism spectrum disorder?
The male to female ratio in autism spectrum disorder is around 4:1. However it seems ASD is not a simple X-linked disorder.
Then how is it possible males are more susceptible than females, if the ...
1
vote
1answer
40 views
How do viroids propagate to other hosts?
As viroids are simply non-encapsidated non-coding RNA molecules, it is difficult to imagine a mechanism for their continual infection, other than horizontal transfer which doesn't seem to be the case. ...
1
vote
1answer
53 views
Breaking of fats
There is a question I encountered.
Why is fat harder to digest ?
A) It has ester bonds.
B) It is not easily soluble in water.
Which is the most appropriate answer?
1
vote
1answer
26 views
What is a good Microbiology atlas for Bacteriology as online version?
I am looking for a online atlas for Bacteriology, the cost does not matter.
I have been searching SpringerLink, and Amazon but no good online version found.
What is a good atlas for Bacteriology as a ...
7
votes
1answer
90 views
How is the exogenous DNA protected from degradation during bacterial transformation?
During transformation, a bacterium can take up DNA from its environment. A small fraction of bacterial species are known to be naturally competent, meaning that they can engage in this sort of ...
0
votes
1answer
39 views
Sewall Wright for dunces
[This is one more post in my growing "X for dummies/idiots/morons/etc." series.]
I've been enjoying Provine's The origins of theoretical population genetics for the last couple of days, but I must ...
2
votes
1answer
60 views
How do you average Ki values?
It's embarrassing for me to ask this but well such is life. NIMH Psychoactive Drug Screening Program (PDSP) Ki Database is mentioned as the source of the average binding affinity (Ki) values given in ...
3
votes
2answers
22 views
Reflexes & Pathologies including the Vagus Nerve
I only know the vasovagal reflex. I would really appreciate if someone could inform me about the other ones.
About the pathologies, I already know the effects of direct nerve damage. I am talking ...
2
votes
2answers
44 views
Transcription factor binding site located in intron
I have noticed that some TF binding sites are located in the introns of the genes.
I am puzzled about whether the TF only binds to DNA in the initiation stage of transcription and will detach during ...
5
votes
2answers
127 views
What is the distinction between chemokines, cytokines, interferons and interleukins?
They all seem to describe molecules of similar function and many people seem to use them interchangeably.
Also please include any other similar molecules if I've forgotten any in the list above.
0
votes
0answers
44 views
Structure of adenoids
I am not sure this question belongs in biology, but I can't find a more suitable stack exchange site, feel free to delete it if this doesn't fit here.
Also, this question is going to be slightly ...
3
votes
1answer
96 views
Are there records of monozygotic twins in which one experiences androgen insensitivity syndrome
I have given my high school biology students the thought experiment of "What would happen if a researcher induced twinning of a female zygote and then replaced one of the X Chromosomes with a copy of ...
1
vote
0answers
34 views
Low RNA yield, low 260/230 ratio
I extracted total RNA from animal tissue using the Qiagen RNeasy kit, however my RNA yield was extremely low and the 260/230 ratio was around 0.3. This is the protocol I followed:
The animal ...
2
votes
1answer
115 views
How do Benzodiazepines induce Rewarding (Euphoric) effects?
Benzodiazepines are a class of drugs that serve as positive allosteric modulators of the GABAA receptor by binding to their own "site" on the aforementioned receptor. By doing this they produce ...
4
votes
1answer
70 views
How does skin healing work?
I stacked my bike and split my head right open. About three weeks later the scab falls off and the skin is sealed over, like magic! How does it all work? How does the brain know that part of the ...
0
votes
0answers
31 views
Polymorphism in cnidarians?
The phenomenon of polymorphism in cnidarians is a particularly a troubling one, at least to me. I gather that it essentially refers to existence of various different forms or rather kinds of ...
4
votes
2answers
112 views
How does fever physically work?
What is the physical mechanism that causes temperature to rise during a fever? I know that somehow the hypothalamus "orders" to increase the standard body temperature regulation, and this should ...
0
votes
1answer
42 views
What are the differences between G+ and G- bacteria?
The distinction between Gram-positive and Gram-negative bacteria is based upon the Gram staining method, that reflects the bacterial wall physical properties.
However, this classification involves ...
-1
votes
0answers
24 views
Site related to forest research [closed]
Does anyone know any website(like- elance, odesk for IT) for forest research related outsourcing/job?
4
votes
1answer
40 views
Are there any bacteria, in our environment, able to break down nitrate under aerobic conditions?
Given a fix volume of water saturated with dissolved oxygen through aeration. Suppose that ammonium, Nitrosomonas, and Nitrobacter are always available in the water. We know that some of the ammonium ...
5
votes
1answer
69 views
Is there a DNA test to identify dog mixes?
We adopted a dog at the age of two. Our vet said it was a mix of an Australian Shepherd and Border Collie, which we've told everyone. Based on markings, I think it's likely. I am wondering, however, ...
3
votes
1answer
41 views
How does a virus take control over the host cell?
When the virus integrates its DNA with the hosts and enters the lytic pathway, do the viral proteins that produced destroy the cells DNA? Do they deactivate it? Also does the cell function in the same ...
1
vote
1answer
32 views
Do Acyl Carrier Proteins and Conenzyme A have similar reactivity?
In terms of the reactions they undergo are they roughly equivalent groups?
1
vote
0answers
17 views
Is there a biological process which causes organs to atrophy in response to enivronmental stressors?
I am aware of what happens when the body experiences starvation and breaksdown the muscles in the body for protein sources and the other processes that happen in such a scenario.
However, i wondered ...
7
votes
1answer
66 views
Why does oxygen bind to hemoglobin in an specific angle?
There is an specific angle of the bond between oxygen and hemoglobin in lungs, which I don't know, but what interests me more is the question, why is it specific?
3
votes
1answer
50 views
Highly spherical Radiolaria; does this image accurately depict the organism?
If I understand correctly, Cenosphaera spp. is a type of Radiolaria, which is a type of zooplankton. The following is an image of Cenosphaera spp. is from the supplementary material (Figure S2) of ...
2
votes
2answers
29 views
How is antibody production stopped?
Once clonal selection is done , B cells would start dividing and producing antibodies.
So, after an antigen is eliminated , what stops the division of B cells and antibody production?
19
votes
2answers
3k views
If a human takes antibiotics are all bacteria in the body killed?
From my basic understanding, antibiotics kill living things, bacteria for example.
Do the antibiotics consumed by a human-being distinguish between what they kill? Or do they just kill every bacteria ...
7
votes
1answer
101 views
What is the evolutionary reason behind the fragility of teeth?
Almost all organs in the human body have a rather large threshold within which the organ or tissue is capable of repairing itself using materials supplied by the body, whether it's made from organic ...
0
votes
3answers
57 views
What are the allowed evolution operators (on protein encoding sequences)?
What are the evolution operators, meaning allowed actions on the DNA sequence that encodes a protein.
I assume all evolution of genes is a result of duplication errors. So an answer could look ...
