4
votes
1answer
338 views

Why are eggs “egg” shaped?

Is there a reason as to why chickens lay "egg" shaped eggs, as opposed to spherically shaped eggs (or a random shape)? <--- Main Question For extra points (actually just to add more words in ...
18
votes
1answer
1k views

Is kissing a natural human activity?

The word natural here is meant in contrast to it being a sociological construct. Is kissing in all its forms something natural for humans? Is it instinctively erotic? Or is it just a conventional ...
1
vote
0answers
27 views

Does regulate always mean suppress when it comes to heteroreceptors?

Do heteroreceptors always suppress the release of the neurotransmitter they regulate upon their (the heteroreceptor's) activation?
4
votes
2answers
164 views

What is the purpose of the adrenal medulla?

The adrenal medulla is less of a 'real' endocrine organ like the others in the endocrine system and much more an extension of the sympathetic nervous system. In fact, its chromaffin cells are modified ...
9
votes
2answers
1k views

Why can't a human regenerate limbs like some other species?

When a person's arm is amputated, the arm will no longer be able to grow back. However, in salamanders, the arm actually grows back. In comparison to a human, what is really happening to the cells ...
1
vote
1answer
75 views

Hearing system as in visual system: exists well also - in protecting the inner mechanical parts of both sensing systems - a similarity?

I prefer answers, not just discussing. In the mechanical part of the human eye the control system to protect for overload of the diaphragm in the iris with a strong coupling to the light intensity ...
9
votes
2answers
152 views

Is there any difference in terms of personal healthcare between complete DNA sequencing and SNPs genotyping?

There are several companies (most notably 23andMe) providing SNP genotyping for individuals claiming that there is no sense for individual in obtaining full genome sequence since only small part of it ...
5
votes
1answer
92 views

Are there known minimal marine ecosystems that are stable?

A more entertaining phrasing of the question would be "what would a marine ecologist put into a perfect aquarium?" I was reading about Prochlorococcus, among other photoautotrophs, and found that ...
5
votes
4answers
2k views

Why Do Ruminants Require A Multi-Compartment Stomach To Digest Food?

Cows, camels, sheep, goats, etc being ruminants must chew their food repeatedly by regurgitating their food from their first stomach compartment and chewing their 'cud'. This then finer chewed ...
6
votes
1answer
5k views

How long will norovirus live?

I hope this is the right place to ask. I subscribe to several Stack Exchange threads, and regard them as the best internet forum for genuine and credible answers. I spent last evening talking to ...
2
votes
0answers
11 views

Difference between Diffuse Optical Tomography and Optical Tomography

What are there the differences between these two modalities? Diffuse Optical Tomography (DOT) Optical Tomography (OT) Are there forms of OT that are not DOT?
13
votes
2answers
409 views

Evolution in 37 years, is it possible?

I am confused, can evolution ( speciation ) really occur in such a short time ? In 1971, biologists moved five adult pairs of Italian wall lizards from their home island of Pod Kopiste, in the ...
12
votes
3answers
915 views

How did the huge dinosaurs cope with gravity and loads on bones, etc.?

It's very costly to be a huge animal. Your mass grows in cube when you scale up, but you still only have two/four legs to support the same weight. This increases the pressure that your body needs to ...
3
votes
1answer
175 views

Neuroscience of temperature regulation and perception

The hypothalamus is known to be important in the regulation of body temperature, but I'm curious whether anyone knows about the neurocircuitry of perceived temperature. It seems like there could be a ...
3
votes
2answers
366 views

Why is the frog genome so much larger than a fish's?

As we have heard in the summaries of the human ENCODE project, 80 per cent of junk DNA appears to have an essential function. Many fish have a genome with only one tenth the size of a usual vertebrate ...
3
votes
1answer
81 views

Atomic force microscopy: depth penetration?

What depth penetration can one typically get with atomic force microscopes? (i.e. how far into the tissue can one image?). I have found numbers on acquisition times (minutes) and spatial resolutions ...
4
votes
1answer
164 views

Possible to Gain More Weight than the Food You Eat

I was wondering if it's possible gain more weight than the mass of the food you eat. At a first look, this is impossible because of conversation of matter, but are there other things to take into ...
5
votes
1answer
2k views

How much gas is exchanged in one human breath?

When we breathe, our lungs absorb a portion of the oxygen in the air, and replace it with some amount of carbon dioxide and water vapor. Typically, how much $O_2$ (in grams, milliliters, or moles for ...
4
votes
1answer
12k views

What factors affect the rate of transpiration in plant leaves?

I'm trying to get my head around factors which affect transpiration in leaves. For example, how would applying petroleum jelly to the surface of plant leaves affect their rate of transpiration? I ...
2
votes
3answers
89 views

Simulating Cell differentiation

I'm a computer programmer deeply interested in Biology. I wish to write a computer simulation for cell differentiation. I understand there will be seemingly impossible challenges in doing this. But ...
6
votes
2answers
185 views

Is warmth/temperature sensed linearly or on a different scale?

I understand that the atmospheric temperature is sensed relative to external body temperature. However, is the sensation of warmth registered linearly, or is it on a logarithmic scale, similar to ...
4
votes
2answers
2k views

Why does alcohol cause the hemolysis of RBC in a large proportion?

I had today an experiment that we put 95% alcohol to the blood which made it completely transparent so hemolysis must have occurred. I started to think about the reasons. I think that this is because ...
4
votes
2answers
813 views

Bone conduction . Different from the normal hearing phenomena in humans?

Bone conduction, is it something different from the normal phenomena of listening through the ears. I checked on some literature . Is it so that Bone conduction has very less to do with the ears and ...
1
vote
1answer
187 views

Why must the alcohol decolorizer be used for 30 seconds or less for Gram staining?

I had today a class in microbiology and my teacher said that the Decolorizer component is the critical one and cannot be more than 30 seconds. The decolorizer has alcohol in high concentration, my ...
4
votes
2answers
170 views

Is every part of a virus important for replication?

Is every component of a virus absolutely essential for its infection and replication in a host cell? Or can you just have parts of it to cause infection?
3
votes
1answer
96 views

Would ovoviparous to viviparous mutation have been gradual? How would that work?

It seems unlikely that an ovoviparous ancestor of mammals long ago could have had a viviparous offspring in a sharp one-generation dividing line, but what would be the gradual steps between egg birth ...
3
votes
1answer
361 views

How do multiple replication forks function without 'colliding', and what is the benefit of this method?

I'm currently reading a little about DNA replication, and have come accross the following statement; Replication starts from a fixed point and is bi-directional ... In Eukaryotes, there are ...
1
vote
1answer
209 views

Cine-MRI versus MRI

Could someone explain the difference between Cine-MRI and MRI? I am reading conflicting things online, such as Cine-MRI uses ECG-gating, or that Cine-MRI takes many images of the same position of the ...
2
votes
0answers
42 views

Is there an entry-level circadian model of serotonin, ghrelin, dopamine and the sense of well being?

I've long been interested in circadian rhythms and recently came across a variety of articles that appear to indicate that the following neurotransmitters, transferases and hormones are connected. ...
1
vote
0answers
42 views

Can viral proteins cause infection? [duplicate]

Possible Duplicate: HIV Rapid Tests Can proteins found on the surface of RNA viruses cause infection without the presence of the actual RNA and other components used in the virus?
8
votes
3answers
283 views

What kind of event would cause the current Mitochondrial Eve to be replaced by a new one?

Apparently all living humans are matrilineal descendants of a single woman who lived 200.000 years ago. She is called Mitochondrial Eve. But at the time she lived there was a different matrilineal ...
4
votes
1answer
142 views

Are serotonin levels in humans affected by light?

I'm reading this Wikipedia article on light therapy and noticed a peculiar statement: The production of the hormone melatonin, a sleep regulator, is inhibited by light and permitted by darkness ...
1
vote
1answer
74 views
13
votes
2answers
469 views

Why are there N's after Sanger sequencing?

After sending a DNA sample for sequencing, the resulting sequence had N's in the beginning and end of the sequence. I know the N's mean that the computer can't tell what the base pair is, but why is ...
5
votes
2answers
6k views

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

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?
3
votes
0answers
23 views

Does Doxylamine have any Influence on the Monoaminergic System?

Does doxylamine have any affects on the monoaminergic system? Specifically I am interested in adrenergic or serotonergic activity but additional information on its dopaminergic activity won't hurt ...
2
votes
1answer
61 views

Which Enzymes are Responsible for the Biodegradation of Noladin Ether?

Which enzymes degrade the CB1-specific endogenous cannabinoid 2-arachidonyl glyceryl ether? (Noladin ether)
2
votes
1answer
45 views

Which Enzymes are Responsible for the Biodegradation of Beta-endorphin?

Which enzymes are responsible for the biodegradation of the endogenous opioid peptide, beta-endorphin?
2
votes
2answers
112 views

Possibility of orthogonal view for a creature?

Just a pure curiosity: Does there exist a creature with an orthogonal view to the world instead of perspective? What would be an optical explanation for possibility/impossibility?
2
votes
1answer
72 views

Are humans hardwired to continue gathering resources after the costs outweigh the benefits?

An animal will stop foraging in a berry bush if the perceived cost of searching for berries remaining is greater than the cost of finding another bush which isn't as picked over. People do the same ...
3
votes
1answer
305 views

Questions regarding ELISA

I have recently peformed an ELISA (Enzyme-linked immunosorbent assay), but I still have some questions, let me first outline what I did: We had a number (20) of tubes containing fake 'bodily fluids' ...
-2
votes
1answer
98 views

Good place to ask health based questions? [closed]

I like the development of biology.stackexchange.com, but it is still in an early stage and far from perfection. While we develop it further, could you guys help me finding places to ask questions ...
5
votes
1answer
49 views

Can paper/plastic currency serve as a medium for pathogens?

http://www.nytimes.com/2009/12/15/health/15real.html seems to indicate for a surface, to serve as a medium, the following properties are relevant animation humidity temperature The article ...
4
votes
1answer
146 views

Conjugate secondary antibody

Why is the secondary antibody conjugated to the enzyme in ELISA, instead of the primary antibody? Wouldn't it be easier to conjugate the enzyme to the primary antibody?
6
votes
3answers
758 views

How to map the Gene name to its Gene Symbol?

I am learning in Gene data lately so I apologize for the silly questions in advance. I read a paper for a cancer on human which found some important genes. For example, the paper listed one of genes ...
2
votes
1answer
205 views

Can Taq polymerase be used instead of polymerase Vent exo (-)?

Instead of using polymerase Vent exo (-), can I go with the usual Taq polymerase? Do the PCR conditions change (the temperature and master mix concentrations ) in the these two conditions? Do the ...
4
votes
1answer
172 views

How does a tiger have stripes?

A vague question, but let me try to explain. My friend explained to me that in females, some cells use one X chromosome, while all others use the other X chromosome. This can result in some ...
3
votes
2answers
386 views

JMol “calculate HBONDS”: which atom is the donor/acceptor?

JMol can be used to identify Hydrogen bonds in proteins by the script "calculate HBONDS". By outputting the state of the network, we can obtain a lisdt of H-bonds. Here's one line from an example ...
2
votes
1answer
57 views

Is it ok for Chili pepper plant's fruits to fall into its soil?

I wonder if Chili pepper's fruits which fall into the soil near the plant will harm it, since the peppers are so spicy for people.
2
votes
0answers
28 views

Where might I find a list of all recorded instincts by species? [closed]

Where might I find a list of all recorded instincts (possibly with all other attributes) by species? Thanks, Chenz

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