3
votes
1answer
32 views

Which part of oranges contain fiber?

I think it's pith, but here (non-english country) many chef suggest orange's vascular veins which look "fibrous" and have similar translated word with "fiber" itself. Please enlighten me which?
4
votes
3answers
54 views

Is territoriality only the domain of the male of a species?

Is territoriality (recognizing a geographic location, and challenging another member of the same species and gender) only in the domain of the male of a species? Are there any species out there where ...
8
votes
2answers
444 views

Would exposure to a strong magnetic field have deleterious effect on the human?

This article states of a 25T magnet, ".. If are ever caught in one of these devices, let’s just say you probably won’t live to tell the tale." Is the above statement in order? What effect would ...
4
votes
3answers
131 views

Good book on Origin of Life [closed]

What is a book that goes into reasonable detail (but isn't textbook-level technical) about the origin of earth and in particular the origin of life on earth? Something intended for a broad audience, ...
7
votes
1answer
954 views

How does a single-stranded RNA bind to a double-stranded DNA to form a “triplex structure”?

If you have a single-stranded RNA that is complementary to a double-stranded DNA, how do they interact to form what my prof. calls a "triplex structure"? e.g. ...
4
votes
1answer
133 views

Functionality of vitamin A, Bx, C, D, E, K as used in cosmetics for the skin?

I was wondering if someone can compare the functionality of vitamin A, Bx (x means numbers, such as 1, 2, 3, ...), C, D, E, K in the skin? They are used in cosmetics but what is their actual effect? ...
5
votes
3answers
124 views

Does the entire surface of the earth contain organisms?

Does the entire surface of the earth contain organisms? My teacher mentioned that in some parts of the earth, there aren't any organism. Is this true? Thanks in advance.
1
vote
3answers
193 views

Action Potential Distribution On Synapses

This is a biology+physics question. Since there is no biology section, I am asking here. In brain, when a neuron reaches to threshold value, it fires an action potential. In most graphics, that is ...
5
votes
1answer
713 views

How do neurons form new connections in brain plasticity?

I've been reading about brain plasticity and how the brain can "rewire" itself. One of the things that is not clear to me - how neurons can establish new connections. Does this rewiring mean that ...
3
votes
2answers
1k views

Why is Paracetamol so great?

Every time I get ill (cold, flu etc) I take a couple of these wonderful tablets for up to 4 times a day and I, eventually, get better. What exactly is paracetamol? Why is it so effective and is it ...
7
votes
2answers
161 views

What measures are commonly used for the complexity of an organism?

I'm aware of measures like number of distinct cell types being used as a measurement of complexity in biology, for example in the G-value paradox. But this doesn't really help for unicellular ...
5
votes
1answer
211 views

Are tongues red because they contain blood?

Many animals have red tongues, though not all of them - blue-tongued skinks and giraffes come to mind. Are they red because of the blood (and therefore haemoglobin) in them? It sounds plausible, but ...
6
votes
1answer
610 views

How efficient is the sodium-potassium pump ?

I am reading about transportation of ions in a cell. It is necessary to transport sodium back out and potassium back in, against their electrochemical gradient. This task is carried out by ...
3
votes
1answer
99 views

Cell growth conditions for preparing electrocompetent cells

Usually the protocol for preparing electrocompetent E. coli cells calls for growing the cells at 37deg and 225rpms until they reach OD of 0.3. I was wondering, is there any reason they should grow at ...
2
votes
1answer
114 views

How can I compare rates of evolution for two sets of proteins?

I have a list of candidate proteins as the result of my analysis. I am now trying to find various characteristics that they have in common. One of the things I would like to check is if my candidates ...
1
vote
2answers
183 views

Do any cells change in size or mass as mammals grow?

That is to say, are there cells that, between infancy and adulthood, get larger? Or is all growth done entirely via cell division? I'm wondering if it is safe to assume that the approximate number ...
3
votes
1answer
341 views

Do adipose cells divide in adults?

I have a dim recollection of having heard that when humans gain weight, adipose cells just get larger, rather than dividing. True?
1
vote
1answer
60 views

In a human, what non-germline cells have the highest/lowest mass?

I'm just curious which cells are largest/smallest in the human body other than sperm/ova.
2
votes
1answer
126 views

Histone marks mechanism

I am slightly confused about the mechanisms that makes histone modifications associate with gene expression. That is, H3K36me3 is believed to be present in actively transcribed genes, H3K27me3 in ...
3
votes
3answers
639 views

What makes urine smell acrid?

Occasionally, after someone's been, there is an awful acrid smell lying about long after them. What causes this? The food that they've eaten? Urea less dilute due to dehydration? If it helps I've ...
2
votes
1answer
101 views

Where does an organism store reserves of amino acids?

Where does an organism store reserves of the amino acids it needs to build various proteins it needs -- in the liver ? in the blood ? in every cell ? Thanks
6
votes
1answer
6k views

Will a bone marrow transplant change one's blood type?

Will a bone marrow transplant change one's blood type? Or is the donor blood type matched with the person before transplant?
5
votes
2answers
159 views

How to get smallest subtree containing a set of nodes from BioPhylo?

I'm testing out various phylogenetic libraries in Python. I want to read in a Newick tree, then, given a list of taxa, generate the smallest tree that contains them all. This task is quite simple and ...
6
votes
1answer
78 views

What are the biological mechanisms behind the increase in cancer risk and alcohol consumption?

Alcohol consumption is known to be a risk factor for developing cancer. Compared to obvious causes like tobacco where one is exposed to known carcinogens, I don't see an obvious mechanism by which ...
0
votes
2answers
307 views

Why do living organisms replicate itself or procreate

Why do living organisms spontaneously replicate itself or "procreate" (my understanding is that it does). From a uni-cellular and micro-organism point of view. Is there some sort of stimulant in the ...
4
votes
4answers
893 views

Multiple sequence alignment - how to align everything to 1 gene sequence?

I'm having trouble aligning 3 sequences together - the total gene (~2500bp) and the forward and reverse sequences that are ~1000bp in length. Now I'm using Clustal X2, but the problem is that the ...
4
votes
2answers
589 views

Why is Botulinum toxin the most potent poison known?

Botulinum toxin (trade name Botox) inhibits acetylcholine release in neurons and causes botulism, an acute paralytic disease which leads to nerve degeneration and takes a long time to recover. I've ...
1
vote
1answer
84 views

Interpreting SNP-in-gene associations from GWAS studies

For most SNPs identified in GWAS studies, is the underlying assumption that if it is indeed associated with a phenotype (and lets assume its associated because it affects protein function), that you ...
3
votes
1answer
61 views

Nucleotide frequencies in Kimura's two-parameter model

Here's an excerpt about Kimura's two-parameter model from Felsenstein's Inferring Phylogenies: "The model is symmetrical, and one can immediately see that, after enough time has elapsed, it ...
2
votes
3answers
440 views

Is there such thing as “half-life” of dopamine?

If a dopamine is released at T=0 and binds to receptor D2, what determines the time when the concentration of this neurotransmitter bound to the receptor reaches half of the original concentration? In ...
3
votes
0answers
217 views

Why does vision go blurry after microscope use, and how to prevent it? [closed]

After using a binocular microscope recently for about 20 minutes, my vision went blurry and for an hour or so it was much harder to read small text. This occurs to a (far) lesser extent whenever I use ...
7
votes
2answers
75 views

What is the benefit of near-emptying the bloodstream in the mammalian kidney?

In the normal function of the kidney, the bloodstream is near emptied of fluids as it moves through the glomerulus, in which glomerular filtrate is formed. As it proceeds through the Nephron, a ...
2
votes
1answer
90 views

Have there been any experiments that duplicate chromosome copies from 23*2 to 23*3 or 23*4?

Deinococcus radiodurans is an amazing bacterium with a fantastic survival rate. It can survive to high doses of radiation, in a complete vacuum and in hydrochloric acid. How does this bacterium ...
2
votes
1answer
71 views

Are genes associated with obesity selected for?

I've read that there are several SNPs associated with increased risk of clinical or morbid obesity. I was wondering if there is any evidence that these are under positive selection. Would you expect ...
5
votes
3answers
206 views

Is Leptin Stimulated by Insulin Alone?

What is the mechanism of insulin stimulation in the human body? Is leptin release stimulated by circulating insulin directly? Which other factors are involved in the level of insulin release? My goal ...
10
votes
1answer
549 views

Could a fetus properly develop in micro/zero-gravity?

I suppose another way of looking at the question is: how important is gravity for the development of mammal fetuses? And if things would go wrong, what sort of things would they be, and what would be ...
6
votes
1answer
73 views

What mechanisms tell temperate trees when to drop leaves?

I've been looking around and cannot find a definite answer on what it is that tells trees to change their metabolism and drop leaves. I see that such activity is called Deciduous. What interests me ...
6
votes
2answers
107 views

DAM enzyme distances move along the genome

I am fusing a protein with a Dam enzyme (http://en.wikipedia.org/wiki/Dam_(methylase)). The idea is that when the protein binds to the DNA, the Dam enzyme will start methylating nearby GATC sites, ...
5
votes
1answer
937 views

High Glucose vs Low Glucose DMEM for Cell Culture

I've noticed that in mammalian cell culture, there are often two types of DMEM available. High Glucose and Low Glucose. Does it matter which type I use for culturing of cells (e.g. Hela or HEK293)? ...
4
votes
1answer
307 views

Do effects of caffeine on human body change with habitual use?

I've been reading about homeostatic nature of a lot of neurobiological processes - the brain is trying to maintain a balance by desensitizing receptors, re-uptaking and breaking down ...
3
votes
2answers
93 views

Is there a timeline for the frequency of evolution of any species?

Evolution is traditionally spoken of as an inherited change over generations. Does evolution happen one change at a time - or are there multiple changes occurring between two successive generations? ...
11
votes
4answers
25k views

What is the armpit hair for?

Modern human beings, especially women, cut their armpit hair. It seems to me the armpit hair is trivial/useless. Shortly speaking, what is the armpit hair for?
2
votes
1answer
155 views

Are inflammation and anxiety connected?

I've been reading a curious paper about the use of cannabis, and one of the passages piqued my interest: There’s also been a lot of work done on another constituent of marijuana, cannabinoid, ...
2
votes
1answer
131 views

By What Mechanism can Felines Reverse Diabetes?

To my knowledge house cats (and likely other felines) are the only animal able to go into remission after onset of Type 2 diabetes mellitus. I don't have a reference, this has been by peers in my ...
2
votes
1answer
31 views

What range of dose should be used?

This is a dose-response experiment testing a new cancer drug. the darker line represents cancer cells. what range of dose should be used? I think it's 2-4 because this affects cancer cells only. is ...
4
votes
1answer
163 views

Why do we think chronic inflammation can cause cancer?

Why do we think chronic inflammation can cause cancer? I know the pathway is not fully understood, but what makes scientists believe that inflammation causes cancer?
1
vote
1answer
312 views

How can the Ames test detect a human carcinogen?

Using the Ames test, we add a mutagen to auxotrophic salmonella with mutations in the histidine pathway and rat liver extract to simulate metabolism. How would we know if the carcinogen is a human ...
2
votes
1answer
184 views

What are evolutionary implications of contraception and reduced childhood mortality rates worldwide?

I've heard the following idea this morning: Before the introduction of contraception, humans conceived quite a lot of babies (there was little to do to avoid that), but the population was kept in ...
2
votes
0answers
94 views

Has anyone ever sucessfully translated xRNA or yRNA?

I've recently been researching the subject of size-expanded nucleobases in alternative genetic sets. Many papers describe the, at least, partial success in replicating xDNA and yDNA, as well as ...
6
votes
1answer
7k views

Do crocodiles age?

I was watching a talk by Michio Kaku and he mentioned that crocodiles (or possibly alligators, I forget offhand) don't actually age -- they can die, but they essentially go through no aging process ...

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