4
votes
1answer
57 views

Parse PDB using DSR-PDB Library

I'm trying to parse ATOM section of a PDB file. I'm using the dsr-pdb library for this purpose. I've encountered a problem. This library interprets CD1 atom of ILE ...
7
votes
1answer
348 views

Can I image Coomassie and GFP in gels at the same time with a fluorescence scanner?

I'm working with a GFP-tagged protein and am routinely using a fluorescence imager (GE Typhoon) and a standard optical scanner to capture fluorescent and absorption images, respectively, of my ...
4
votes
2answers
156 views

Is there a good field methods book that covers terrestrial ecology?

In the past I have used Limnological Analysis by Wetzel and Likens and Methods in Stream Ecology edited by Hauer and Lamberti to develop labs and research methods for courses and projects with an ...
3
votes
1answer
142 views

What is the known maximum ranging distance of a bat's sonar?

Bats are known to navigate by using echo-location. How far away can a bat detect an object by its sonar?
1
vote
1answer
507 views

Why do drugs which are hormones have long half-life?

Hormones normally have short half-life. How is it possible that they have long-life in drugs?
3
votes
1answer
156 views

Were there lifeforms before LUCA?

This question got me thinking about something. LUCA is the last universal common ancestor of all current living organisms, which is a very different definition from the first-ever living organism. Is ...
2
votes
1answer
78 views

Reattaching body parts

Is there any living organism that has the ability to remove and reattach body parts at will? I'm not talking about regeneration (like in starfish). Say I'm chasing prey, and I decide that my tail ...
7
votes
1answer
68 views

Which poison makes seastars inedible to possible predators?

In the new citizen science project (see: Sea Floor Explorer), numbers of seastars, scallops, crustaceans and other animals are counted. Already one can see a heavy bias in favor of seastars, both the ...
5
votes
2answers
280 views

What were the mammal ancestors like 65 million years ago?

What we know about our mammal ancestors that were alive (and survived) at the extinction event 65 million years ago?
2
votes
1answer
568 views

Why does high-voltage mostly shock a person, and even small current kill?

This may be the wrong forum to ask. For instance several people are known to have survived a direct lightning strike; albeit the number of fatalities are probably far larger. Anyway, I found myself ...
6
votes
1answer
644 views

What really happens when a body is tired?

This may be anecdotal; please feel free to vote to close. After staying awake for an extended duration, I usually find myself having to take extra effort to focus my eyes on an object. Similarly ...
13
votes
1answer
7k 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 ...
9
votes
5answers
584 views

Finding and Comparing Homologous Genes

I have a gene of of interest that I would like to compare between homologues. How does one go about finding a gene from known coding sequences across phyla? Afterwards I imagine I could do a Clustal ...
14
votes
1answer
147 views

Has the human 7-day week had any impact on the evolution of species?

Most (if not all) industrialized countries follow a 7-day work week now, such that we are bound to follow a certain weekly trend in matters such as pollution generation, where to go (e.g. stay in town ...
4
votes
1answer
101 views

Are there any websites offering graphs for the light absorption of different enzymes?

I have found graphs for the light absorption of water, haemoglobin, lipids, melanin, etc., but I am having a hard time finding graphs about enzymes. Are there any websites or other reference sources ...
8
votes
1answer
124 views

How realistic is to use DNA for long term storage?

This is mainly a followup question to the recent paper Next-Generation Digital Information Storage in DNA. Personally, while I agree about the data density of the format, I can't help point out the ...
7
votes
2answers
78 views

Should we be looking for extra-terrestrial life on comets?

I have just read What elements are a possible basis for life? and I find myself wondering whether instead of seeking advanced life-forms at remote locales a La SETI, and perhaps fundamentally ...
3
votes
1answer
23 views

Mutation in axillary buds of trees overcoming self-incompatability?

I seem to recall from either reading or lecture that there have been instances of trees that are self-incompatible accumulating enough mutations in an axillary bud that the resulting branch was able ...
8
votes
1answer
427 views

What conditions are necessary for HPL (human pancreatic lipase) to activate?

What conditions are necessary for human pancreatic lipase to activate? Is there an optimal temperature or pH? How quickly does it take effect?
8
votes
1answer
161 views

Is there a program that simulates biology on a molecular level?

Is there a computer program that simulates biology on a molecular level? Software that has rules that simulates the rules of molecular-biology?
2
votes
1answer
189 views

Amount of neurons in the heart

Finding numbers for the amount of neurons in the brain is quite easy. Finding them for other human organs is harder. How many neurons are there in the human heart?
8
votes
1answer
861 views

Disadvantages of unihemispheric sleep

Is is well known fact that marine mammals and some birds can sleep with one brain hemisphere at a time, since it's essential for their survival. However, at least in my opinion, such mechanism would ...
1
vote
1answer
167 views

What does “cellular” mean in this context?

I came across a confusing word when I was reading a Scientific American story, “Controversial Spewed Iron Experiment Succeeds as Carbon Sink” (by David Biello). It goes like this: “One key to the ...
2
votes
2answers
173 views

What does “delineate” mean in this context?

I was reading a Scientific American story, “Controversial Spewed Iron Experiment Succeeds as Carbon Sink” (by David Biello), when I came across this sentence: “The problem for scientists is that ...
2
votes
1answer
330 views

Has the age at which menopause occurs changed throughout history?

I was reading recently that the age of menarche has decreased in the last 150 years, and was wondering if the age of menopause in humans has also changed recently? Would there be selective pressure ...
5
votes
1answer
1k views

Does the light color spectrum and frequency matter for photosynthesis?

Do plants grow differently when given sun light, wolfram lamp, fluorescent light, LED light, infrared, ultraviolet, x-ray, unfocused laser and stroboscope?
2
votes
0answers
21 views

How to seek information on the duration of biological entrainment processes in mammals? [closed]

This is a question that is a little bit hard to define for me. I'm interested in learning more about times of "attractor/entrainment" processes that may take place in the body/brain of mammals, and ...
7
votes
1answer
655 views

Does drinking coffee have negative effects?

From what I collected, coffee is a magical potion that lets you feel energetic, and essentially not-sleepy. But are there any tradeoffs? I mean, if it was so beneficial, wouldn't the human body ...
3
votes
1answer
65 views

Does the Heart Require Gold?

I distinctly remember an episode of NOVA from the early 1980’s that concerned itself with gold. One of the points that was made was that there are trace amounts of gold in the human body, ...
3
votes
1answer
478 views

“Acellular” designation for organisms

Why do some biologists refer to single-celled organisms such as Amoeba and Paramecium as acellular (i.e., without cells) rather than unicellular (i.e., one cell)?
8
votes
1answer
2k views

How does the NAD+/NADH ratio affect lifespan in vertebrates?

Here's the proximate physical implication of the ratio (from the Wikipedia article on NADH). The balance between the oxidized and reduced forms of nicotinamide adenine dinucleotide is called the ...
5
votes
1answer
106 views

How do I prepare a PDB for submission to the Protein Data Bank?

I have a couple structures that are nearly ready to be deposited in the PDB. Out of curiosity, I ran them through the ADIT's precheck tool and they failed with one error after another, as I lacked ...
3
votes
2answers
129 views

Do diurnal birds of prey recognize each other by their appearance?

Just what the title states. I recognize people around me by their facial appearance to begin with, then by their little idiosyncracies; this applies perhaps to most other humans too. We rely pretty ...
7
votes
1answer
108 views

Do goldfish really have a 5 second memory span?

I heard that when people place goldfish in another tank, they just forget where they where previously? True or False ?
5
votes
1answer
584 views

What gives things their colour?

My 6 year old daughter asked me 2 biology-related questions yesterday and I tried my best to answer them with the aid of YouTube videos. One of the questions (I may post the other one too) was ...
8
votes
1answer
205 views

What are the biochemical processes occurring when food spoils?

Let's assume for a minute that microbes themselves and their direct toxic products (i.e. endotoxins) aren't toxic to humans. Let's also discount any innate immune responses the body mounts against the ...
6
votes
1answer
185 views

Do all mushrooms have the same multicellular ancestor?

Do all mushrooms have the same multicellular ancestor? Did that ancestor feature common mushroom elements such as cap, stem, sporofore, vulva, bulb, etc.
1
vote
1answer
30 views

Can a plant be induced to accelerate transpiration?

Just what the title states. I wonder whether it is possible to fire a chemical switch - sort-of like injecting adrenaline in a human, to accelerate a particular process in a plant. For example, ...
2
votes
1answer
82 views

At what substrate concentration will an enzyme work at 40% of its maximum rate if its Km = 0.095M?

The question involves the Michaelis-Menten kinetics equation. Here is what I did: I took the Michaelis-Menten equation, replaced v with 0.4Vmax, canceled the Vmaxes (one on each side), and solved ...
2
votes
1answer
53 views

What type of biome is this?

There is a region that gets about 812mm of precipitation and is mildly hot all year long. I believe this region is a tropical savanna, but I'm not 100% sure. Is this correct?
-1
votes
1answer
4k views

Ramifications and possibility of a diet consuming exclusively of human semen

Semen is a thick, nutritious liquid, rich in vitamins (such as C, B12), amino acids, lipids, monosaccharides (fructose), et cetera. Can semen's ability to fulfill the needs of human organism provide ...
4
votes
2answers
2k views

DNA as an acid? [duplicate]

Possible Duplicate: Does DNA react in all of the ways most other acids do? Even if DNA is made up of nucleotide bases, it is said to be an acid. Why is this?
11
votes
4answers
4k views

Do cows produce milk excessively?

Do cows produce more milk than it is required for their calves? It seems like cows are able to provide milk all the time (all year around). Is it so? Or do they, like other mammals, produce milk only ...
3
votes
1answer
253 views

Ammonium sulphate precipitation assay pH dependence

In general does the pH effect the precipitation, e.g. would a pH of 6 cause less precipitation than pH 7.5. Or are they unrelated?
2
votes
1answer
102 views

Where are -HCl supplements absorbed in the human digestive system?

I see that quite a lot of drugs and dietary supplements sold in the USA have -HCl(hydrochloride) added to their name. For example pyridoxine hydrochloride for Vitamin B6. I'm interested in knowing ...
4
votes
1answer
234 views

If proteins have an overall charge, how do membrane proteins traverse through the hydrophobic region of the plasma membrane?

These two concepts seem almost contradictory, proteins have a net negative charge due to the amino acids in them each having a small negative charge, yet membrane proteins are able to exist traversing ...
5
votes
1answer
3k views

Do other male mammals except for humans have nipples?

When I grew rabbits, I had a pair, one male and one female. And while the female's nipples were quite prominent, especially after giving birth, I don't remember the male having any nipples at all. Do ...
5
votes
1answer
725 views

Multi-nucleated cells: advantages and examples?

This question arises because I saw that monocytes and leukocytes are commonly called 'mononuclear cells' in the scientific literature. The implication of course being that other immune sub-types are ...
13
votes
2answers
265 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 ...
6
votes
1answer
194 views

Why do the feet of the Gecko Lizard not stick to Teflon surfaces?

I have noticed that lizards feet can stick to walls but not to Teflon surfaces? Why is that?

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