5
votes
1answer
1k 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 ...
0
votes
1answer
87 views

Is there already discovered non-carbon form of life?

I have heard of some rumors going around about a living organism based on non-carbon. Is Has research been done with real form of life based on non-carbon? Or carbon-based life is only type of life ...
5
votes
1answer
126 views

Identify this spider

I found this spider on my balcony in Sunnyvale, CA. It sat in a irregular net. The body was approx. 6mm long. Which species does it belong to?
-2
votes
1answer
96 views

Would I still exist if [closed]

I've been wondering for some time, but say that my mother's egg chose another sperm cell, and a baby was eventually produced. Would I still be born, but end up with different characteristics/features? ...
9
votes
2answers
20k views

Is it possible for a brown eyed parent to have blue eyed child?

Here's the story: A young man has stunning blue eyes. On his mother's side are lots of instances of blue eyes, but on his father's side is no history of blue eyes. When he was born with these bright ...
1
vote
3answers
1k views

Does Darwin's Theory of Evolution refute Terence McKenna theory “Stoned Ape” theory of human evolution?

I haven't read it but I'm asking for a quick answer. As far as I know, Terence McKenna's theory of evolution in humans main concept is that a hominid has tried in their diet psilocybin mushrooms, and ...
9
votes
3answers
7k views

Does our DNA change during our lives?

As far as I know, DNA is the construction protocol of all organisms on Earth. Does it change when influenced by time and environment (physical laws)? As parents with schizophrenia are more likely to ...
2
votes
2answers
595 views

The antibiotic 'kanamycin' in the growing of culture E. coli

I'm a first year student and I'm not sure if I understand correctly the role played by the antibiotic 'kanamycin' in the growing of culture E. coli (Rosetta). Can anybody explain me why we use ...
3
votes
2answers
512 views

How is RNA of retrovirus converted into cDNA?

The retrovirus (oncovirus) contains RNA. It also has a molecule called reverse transcriptase. This molecule transcribes RNA into cDNA. This cDNA is the DNA copy of viral RNA genome RNA has Uracil ...
4
votes
3answers
3k views

What is the equivalent of shutter-speed in Human eye?

I just learned that in video cameras, every frame of the video has its own shutter speed. And I know how frame-rate in human eye works out, well, not completely, hence the question. ...
1
vote
2answers
404 views

what is knob heterochromatin?

I am reading a paper which discusses Maize Genome Structure. Descriptions of the structure is given in the papers introduction. I know about heterochromatin "heterochromatin stains intensely, ...
4
votes
1answer
126 views

Identification of this Salamander

This salamander was found in a small forest pond somewhat near the Oregon coast. In the area are many rough skinned newts and a small number of another type of salamander that I still can't find the ...
8
votes
3answers
145 views

Are there echolocating insects?

Echolocation is the ability to obtain spatial information of the surroundings from echos generated by the animal. There are bats and other vertebrates that naturally use it. I was wondering if this ...
2
votes
2answers
219 views

Basic text/notes on DNA structure (for non-biologists)

I am a mathematics grad student researching knot theory, and I've recently discovered that there is a connection between knot theory and DNA structure (if I understand correctly, when DNA strands ...
6
votes
3answers
241 views

If I built a concrete pool, would it ever contain fish?

Imagine that I built a concrete-walled pool the size of a football field and filled it with fresh water - obtained from another lake but free of bacteria, plantlife, eggs, etc. Would it ever, over ...
0
votes
1answer
56 views

Male behaviour during breeding season

The mountain blue bird build nests to attract females and exhibit aggression towards other males during breeding season. Which of the following is likely to give the birds maximal evolutionary ...
3
votes
1answer
80 views

Fear in elephants

It has been noted that elephants trained for war, as was done occasionally in earlier times, have still shown a tendency to panic in battle much more often when compared to a war horse trained for the ...
1
vote
1answer
64 views

Why are Lymphatic trunks part of the Cardiovascular system?

According to Wikipedia the Terminologia Anatomica (international anatomy standard) the lymphatic trunks are part of the cardiovascular system instead of the lymphoid system. Why did they make that ...
2
votes
1answer
182 views

Need of Creatinine Phosphate

In muscle cells most of the ATP's phosphate is with creatinine phosphate. So why is the displacement of the phosphate group done ? Is it because creatinine phosphate would give it's phosphate more ...
1
vote
1answer
236 views

Change of phase from juvenile to adult in plants

I tried googling this but couldn't get much information on this. Most of the articles were about induction of flowering. I am more interested in knowing what factors influence the conversion of ...
3
votes
2answers
652 views

What is an 'ex vivo' experiment?

Simple terminology question: Is there a hard boundary between in vitro and ex vivo? Is there a hard boundary between in vivo and ex vivo? Suppose a sensory neuron is electrically recorded in the ...
4
votes
3answers
143 views

What makes a metal safe to use for an artificial joint?

What determines if a metal is suitable for transplantation such as in the hip? What I am most interested in however is why might some metals be toxic to animals once in the body?
1
vote
5answers
288 views

Is evolution true as Darwin said? [closed]

I was telling the theory of evolution to my friends. But they asked me for the proof. They said, we are not seeing any such transition species at present. Neither we have such evidence for evolution. ...
2
votes
1answer
41 views

What are the methods for infering genetic interactions?

Is there a classification of methods for inferring genetic interactions? I mean some work published, utilizes genetical genomics data. Is this possible with expression data alone? And how about ...
3
votes
1answer
50 views

Effect of arteriole dilation on vein

If an arteriole leading to a capillary bed is dilated will the pressure in the vein coming out from the bed decrease ? Will the velocity of blood in the vein change ?
0
votes
1answer
259 views

Organelles present in sieve tubes

I know that sieve tubes do not have ribosomes, nuclei and cytoskeletal elements. What other organelles does it not have? Does it have a cytoplasm?
2
votes
1answer
117 views

Rate of Evolution of population of long lived individuals

Is it necessary that rate of evolution of longer lived trees will be lesser than that of annuals ? I understand that new individuals will come up faster in annuals and it may adapt to varying ...
3
votes
0answers
31 views

Division of Polar Body

The first polar body formed after meiosis-I is completed in oocyte, may or may not divide. Why is the statement that "it may or may not divide"? Is it random ?
0
votes
1answer
181 views

Need of X or Y chromosome protein after meiosis

After meiosis each spermatid get either the X chromosome or the Y chromosome. I know that the 4 spermatids formed from 1 spermatogonia are connected by cytoplasm and so the proteins made by X or Y ...
2
votes
1answer
207 views

Do people of the same height walk at the same speed?

I'm working on a project that concerns movement and the human body. Before I begin to experiment, I need an answer to a question I'm sure has an answer, but doesn't Google well. What I need to know ...
5
votes
1answer
65 views

How do rodenticides with delayed effect work?

Most modern rodenticides are claimed to cause death no earlier than several days after ingestion. That's quite strange - once a chemical was ingested it will be absorbed in the digestive system and ...
8
votes
1answer
222 views

Is it a limitation of the eyes, or the brain, that we can't see a moving bullet?

Are the photoreceptors in our eyes not fast enough to register the fast moving bullet, or is the brain not powerful enough to make sense of something happening that fast?
4
votes
3answers
5k views

What's a non-allelic gene?

Non-allelic or non-alletic I stumbled across the term in my Human Genetics textbook. It didn't explain it there, and a quick google search only showed scientific papers that refer to 'recombinations ...
7
votes
1answer
544 views

RNA seq and using of Poly(A) or non-Poly(A) based amplification of RNA

I'm studying "Deep sequencing the circadian and diurnal transcriptome of Drosophila brain" Hughes et al., 2012. I've got some problems with the materials and methods. Before RNAseq, the authors ...
0
votes
1answer
50 views

What happens to potassium after an action potential?

If I understand right, after repolarization, much of the potassium is outside the membrane and much of the sodium / calcium is inside. How does it get back to the original concentrations (i.e. ...
1
vote
1answer
155 views

Is there a human form of estrus?

Now I just learn that estrus is a trait in all mammals except Humans. So does it occur significantly in Humans? Of course I'm aware of the cliched "horny", "aroused" etc., but is it a biological ...
4
votes
1answer
379 views

Which organisms have introns?

From Wikipedia: For example, introns are extremely common within the nuclear genome of higher vertebrates (e.g. humans and mice), where protein-coding genes almost always contain multiple introns, ...
2
votes
1answer
661 views

Glycolysis and Non-Glucose Sugars

In my biology book's section on disaccharide metabolism and glycolysis, it states that sugars other than glucose must be acted upon to enter glycolysis. Let's take sucrose as an example. Sucrose is ...
6
votes
1answer
95 views

Is there a website that shows population sizes?

I'm looking for a website that shows the population sizes of a species (doesn't matter which) as a function of time at a geographic coordinate. Is there a government website or other free database ...
3
votes
0answers
64 views

Deducing synaptic strength from electron micrographs?

There are several promising techniques for connectomics based on iterative sectioning and imaging of tissue with scanning electron microscopes (e.g. FIB-SEM and ATUM) By looking at such micrographs, ...
2
votes
1answer
35 views

Osmoregulatory Acclimatization in amphibians

If a frog is gradually exposed to increasing concentration of salts can they acclimatise or will they die of exosmosis ?
1
vote
1answer
138 views

Hydrophilicity and polarity [closed]

If any given molecule is polar, and is capable of hydrogen bonding, I can be sure that it's hydrophilic. However, are those two the only conditions that make a molecule hydrophilic?
4
votes
1answer
52 views

RNA-seq Data on domestic animal with different environment

I want to find the RNAseq data available on domestic animals in different environments. If microarray data is available, it would be more useful. If you know I would appreciate to inform me.
2
votes
1answer
426 views

Which is the tissue damaging agent in krokodil (street desomorphine)

I've just read about krokodil and saw some quite hideous pictures about what it does to the human body. I guess just desomorphine alone wouldn't have this effect. Which ingredient(s) causes the ...
2
votes
1answer
80 views

Aerobe or facultative anaerobe organism that metabolizes acetate?

I'm assuming bacteria, but will take any suggestions. Organism must survive primarily on the acetate (plus trace elements), but I can give/take electrons, if necessary. Not interested in strict ...
3
votes
1answer
64 views

What is the cause of the spots on this leaf?

On a hiking trip to the Alps I found trees whose leaves showed those spots you see on the picture. I am curious about what the cause is. Higher resolution pictures of front and back side.
3
votes
3answers
79 views

Would Bubling Oxygen Through “Dead Zones” Like A Fish-Tank Make Much Difference?

I am a dilettante when it comes to dead zones. I realize that they vary from fleeting algal blooms to continuous dead zones. For the continuous dead zones it would seem to me that adding a "bubbler" ...
2
votes
1answer
652 views

Why are urban birds still scared of humans?

I understand that animals are naturally scared of humans because we basically slaughtered every living thing we found in our way for millennia. How long does it take for them to genetically 'forget' ...
2
votes
1answer
54 views

Can a chicken's lard become liquid depending on its diet?

On Cooking.se, somebody asked a question about the fat in chicken stock sometimes being liquid and sometimes solid once the stock has cooled. The only answer until now suggests that the difference is ...
2
votes
1answer
130 views

What is the full name of E. G. Gray?

E. G. Gray is Neuro scientist who found and described first the two major morphologically defined synapse types (Gray Type I (asymmetric) and II (symmetric)) in his work E G Gray (Oct. 1959). ...

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