All Questions

10
votes
1answer
142 views

Are there specific conditions that allow humans to see ultraviolet wavelengths

It is fairly common knowledge that the lens in its normal state absorbs ultraviolet (UV) radiation. An interesting notion has come up from time to time in my reading that suggests there are a small ...
10
votes
1answer
498 views

Is there are evolutionary explanation for why humans and primates are ticklish? How might it have evolved?

Tickling is a rather interesting phenomenon: When humans or apes are touched in certain areas like the armpits or sides, we respond with laughter AND frantic attempts to stop the assault. Obviously ...
10
votes
1answer
312 views

Can Naegleria fowleri enter through wounds into the bloodstream?

All the sources I've read said that Naegleria fowleri enters the brain through the nose. But lets say that someone had cuts on their arm or leg and they are swimming in water that is conducive to ...
10
votes
1answer
128 views

What portions of the brain have drastic changes in activation when we “sense” someone is there?

I was watching an old Arnold Schwarzenegger movie ("Commando") where he plays an elite soldier (surprise). An enemy tries to sneak up on him, and Arnold says that he smelled the other guy ...
9
votes
3answers
110 views

Standard letter for 5-methylcytosine

I'm working on a piece of software that computes melting temperatures for nucleic acid duplexes, and I'm about to add support for 5-methylcytosine as a nucleotide base. At the moment, the bases ...
9
votes
3answers
3k views

Why does human facial and head hair continue to grow?

Many people can grow extremely long head hair and facial hair. Are there evolutionary theories as to why this is the case? It seems like having long hair could be a disadvantage, and extremely long ...
9
votes
1answer
2k views

Why is GTP gamma S non hydrolyzable?

GTP gamma S is routinely used in studies of G proteins to stably activate the G protein. Comparing the structures of GTP gamma S and GTP, the Sulphur atom replaces the Oxygen attached to the leaving ...
9
votes
3answers
391 views

Source of DNA sequences

I'm working on a project where I am taking DNA sequences and translating the codons into musical notes. I have some good ideas of how to do this, I'm just not sure what sequences to work with. My case ...
9
votes
1answer
252 views

How are there alternative initiation codons?

According to wikipedia and the original complete sequence of the K-12 genome, there are multiple non-AUG start codons such as GUG and UUG. How is this possible? I'm particularly curious about the ...
9
votes
1answer
1k views

What's the effect of oxygen deficit on plants?

As I know all cells require oxygen. So my question is how efficiently can plants operate in no-oxygen atmosphere? Do all plants produce enough oxygen for themselves? Can they consume their own oxygen ...
9
votes
2answers
138 views

Acknowledging differentiation of species, in historical times

This is at least partly an historical question, and I am not even remotely a biologist of any sort, so apologies beforehand if it's a little obscure. I often wonder how many distinctions were made in ...
9
votes
4answers
1k views

What determines a successful protein expression in E. coli?

Some proteins express well in a heterologous host; others- don't. A few requirements are known to determine the protein expression, like a strong promoter (like T7) for transcription and a strong ...
8
votes
1answer
124 views

How should I feed and keep an ant queen?

I have captured wandering ant queen. I guess she was just fertilised and was looking for a place to start a hive. I'd like to create my own ant hive in artificial environment. I unfortunately only ...
8
votes
2answers
1k views

why is AUG the initiation codon?

Is there any reason why AUG is the initiation codon ? Why is there a need for an initiation codon ? Can't translation start with different codons?
8
votes
1answer
9k views

What is the composition of human feces?

Are there any studies or general information on the composition of human feces? I'd specifically like to know the percentage of carbohydrates and amino acids relative to the amount that was ingested ...
8
votes
3answers
269 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 ...
8
votes
1answer
4k views

How does sodium in one's diet affect blood pressure?

Due to high blood pressure, my doctor has recommended I go on a low-sodium diet. So, that got me wondering what it is about sodium that drives this recommendation? What does sodium do to a body ...
8
votes
2answers
183 views

How are antibodies designed?

Antibodies have the ability of recognising highly specific peptide sequences and bind it at their antigen-binding site. This ability is harnessed as a tool in research to purify target structures in ...
8
votes
3answers
234 views

Is there any documented evidence for suicide among vertebrates other than humans?

Is there any documented evidence for suicide among vertebrates other than humans? Lemmings not accepted !
8
votes
1answer
108 views

Why can't we breed watermelons without any remaining seeds in the flesh?

Watermelon is just starting to come in season in the northeastern U.S., and having a seedless watermelon is convenient. The only downside is, the "seedless" almost always still have the immature, ...
8
votes
1answer
224 views

How long does it take for E. coli to shift feedstocks?

With our fermentations we're noticing that it takes an appreciable amount of time for E. coli (K12 variant) to change from being metabolically streamlined on amino acids to being metabolically ...
7
votes
1answer
108 views

Why can you not tickle yourself?

It's the age old question, why can't we tickle ourselves? If you rub your fingers along your skin, sure there's sensation but you don't break down into a laughing fit (at least I don't :P), if someone ...
7
votes
1answer
95 views

obesity risk and single gene polymorphisms

I read a fairly recent meta-analysis of studies into the association between adult obesity and polymorphisms of the FTO gene (Peng et al., 2011). The paper looked at 59 studies and found that "FTO may ...
7
votes
2answers
264 views

What is the eye muscle status when you stare at distant view through a glass wall?

The book said when you look at object close to you, the eye muscles contract and vice versa. I wonder what will be the status of the eye muscles when I stare at distance view (such as a mountain) ...
6
votes
1answer
132 views

Alfred Jost's rabbit experiment: how did he actually do it?

I was watching a Crash Course on Biology YouTube video by Hank Green: Great Glands - Your Endocrine System. Hank humorously describes a sex determination experiment by Alfred Jost as follows ...
6
votes
2answers
149 views

How would the human body adjust to sleep times if we were to live in a place with different day lengths?

You sleep at night and are active during the day that's how things work for humans, but theoretically if a human whose parents lived on earth were to be born in another planet resembling earth but the ...
6
votes
1answer
4k views

Why can cats interpret things on a monitor/tv, but dogs cannot?

E.g. you can see a lot of videos where cats are smashing some mouse or spider on an ipad, but I have never seen it with a dog. I have a dog myself and I know that he sometimes responds to the sounds ...
6
votes
2answers
141 views

Can any species be bred selectively/engineered to become as diverse looking as dogs?

I've done some research and it appears that dogs are the most diverse looking single species of mammals. The questions that interest me is - are dogs special in respect to genes/gene activation ...
6
votes
1answer
286 views

Has any large-scale origin-of-life simulation/experiment been done?

I have been thinking a little about the origins of life, and was further inspired by this question: How did the first self replicating organism come into existence? I can accept that we don't quite ...
6
votes
2answers
8k views

Can positive and negative blood type of a couple lead to miscarriage?

I want to know can $+ve$ and $-ve$ blood group of a couple could be a cause of miscarriage in pregnancy?
6
votes
1answer
234 views

Is there a normal human melatonin concentration to light level curve?

I'm looking for a graph or a curve that would show the typical concentration of melatonin in blood or saliva for humans over 24 hours. It would be good to know the photoperiod for the same human as ...
6
votes
2answers
159 views

Do omnivore mammals vary food preferences based on dietary needs?

I'm wandering if mammals that can eat many different kinds of food (omnivores) vary their preference for food not only based on the availability, but also based on dietary needs? I'm looking at this ...
6
votes
1answer
127 views

Number of spindle fibres during Metaphase?

During metaphase, the chromosomes are arranged on the equatorial plate and are attached to spindle fibres. After S phase, can the cell be said to attain the configuration of 4n? Also, during ...
6
votes
1answer
346 views

Photosynthetic Pigments vs. Chloroplasts

What is the difference between Photosynthetic Pigments and Chloroplasts? I know plants have both but Prokaryotes (Bacteria and Archeae) only have the former.
6
votes
1answer
144 views

Alternatives to fittest-win and Moran processes as simple mathematical models of selection

When modeling selective sweeps as a micro-building block in models of macroevolution (not to be confused with misuses of this in creationist arguments), I use the fittest-win model of selection as a ...
6
votes
2answers
228 views

Is there such thing as a generic “metabolic type”?

A while ago I picked up a book called "Eat right for your metabolic type". The book discussed the effects of the endocrine system on the overall shape and the speed of metabolism. The book outlined ...
6
votes
2answers
647 views

For how long and how cold should I perform ethanol/isopropanol precipitations of RNA or DNA?

Precipitating nucleic acids using either isopropanol or ethanol is a very common operation, and I've read some very different protocols on the duration and temperature the precipitation should be ...
6
votes
1answer
631 views

How does water move throughout plants?

I haven't yet found a decent explanation for how water moves throughout plants. It does seem to travel more efficiently upward than out or down. Why is that? How does it travel through the plant?
6
votes
3answers
2k views

Why does so much variation exist within species?

My last phrasing of this question did not go down well, so I will try again. The genotype of species is not always the same. If you ask yourself why not all of these possible expressions except one ...
6
votes
2answers
833 views

How does an inhibitory synapse communicate to the cell body of a neuron?

I picture a neuron as having multiple trees of dendrites attached to the cell body with a single axon leaving the cell body. I believe the cell body near the axon root makes the decision to fire or ...
6
votes
3answers
281 views

Where can I find the common names for the zoology taxonomy?

Forgive me if my question does not belong here or if I'm using incorrect terms, but I'm not educated in biology at all. I'm investigating the workings of the biological classification system. I was ...
5
votes
2answers
47 views

Problems understanding membrane potential

I understand that membrane potential is the difference of the extracellular and intracellular ionic charges, due to their concentrations. We say that the extracellular space has a charge of 0 and then ...
5
votes
2answers
204 views

How is it possible to even hope for an ebola epidemic of this current size to remain contained to a relatively small part of Africa?

As of 2014-09-14 at least 5347 cases of ebola have been identitied. Some estimates are much higher. While experts are sounding the alarm to try to get sufficient resources to contain the outbreak, ...
5
votes
1answer
65 views

Scale up of Bacterial growth from 250mL to 1-5L?

I am currently growing up a specific strain of E.Coli with a knockout in 40mL of growth medium (LB) in a 250mL shaker flask... My ultimate goal is to scale up this process to a 1-5L large scale setup ...
5
votes
3answers
152 views

What are some examples of genes that code for multiple proteins?

The title pretty much says it all. It is widely taught that a gene in a eukaryotic system could produce more than one protein due to post-transcriptional modification, but I do not believe I have come ...
5
votes
1answer
220 views

Do ants within a colony ever fight or come to conflict?

I'm investigating how hierarchical groups of a larger organization with a common goal tend to come to conflict with one another over time. As you decompose a large group (for example a corporation), ...
5
votes
1answer
260 views

Empirical evidence for species selection

Do we have any empirical evidence in favor of species (or lineage) selection? Do we know some cases that can only be explained (or seem to be only explained) by lineage selection? What are today the ...
5
votes
1answer
689 views

Why do organisms excrete nitrogenous wastes?

All plants and animals excrete nitrogenous wastes in the form of urea, uric acid or ammonia. But isn't that a bit of a waste? I mean, there is a shortage of biologically available oxygen in the ...
5
votes
3answers
2k views

Why does it hurt when you take sweets, if you have cavities in your teeth?

When you have cavities in your teeth taking any sweetend drinks or food causes sensitivity or pain. What could be the reason?
5
votes
2answers
205 views

What are common causes of unexpected ligation products?

I digested two plasmids, one with EcoRI and AgeI and the other with EcoRI and XmaI. Digests looked as expected, so I purified the respective fragments and set up the T4 DNA ligation (AgeI and XmaI ...

15 30 50 per page